Гидроаккумулятор и реле давления. Настраиваем правильно

Рис1. Гидроаккумулятор

    При сборке насосной станции важнейшим вопросом является настройка реле давления и гидроаккумулятора (Рис.1). От правильно выставленных пределов зависит не только удобство пользования системой водоснабжения, но и продолжительность эксплуатации некоторых элементов насосной станции.

    Часто возникает впечатление, что все те советы, которые можно найти в сети Интернет по настройке давлений, не просто далеки от реальности, но и вредны, так как не соответствуют действительности. Вот и приходится каждому разбираться в принципах работы и настройке самостоятельно. В данной статье приводится порядок действий по настройке давлений, следуя которым удалось отрегулировать работу насосной станции, активно эксплуатируемой уже пятый год.

Рис2. Крышка золотника

Гидроаккумулятор – не только вода. Немного теории

    Внутри металлического бака гидроаккумулятора (ГА) находится резиновая емкость (груша). Насос нагнетает воду именно в грушу. В пространство между стенками бака и емкостью через золотник закачивается воздух. Чем больше воды в груше, тем сильнее сжат воздух и тем выше его давление, стремящееся вытолкнуть воду обратно. Также существуют мембранные модели ГА, в которых металлический бак разделен пополам мембраной, с одной стороны которой находится воздух, а с другой вода.

Рис3. Проверка давления

Практика. Воздух

    Итак, вот он – купленный гидроаккумулятор. Прежде всего, необходимо определить давление воздуха в нем. Несмотря на то, что производитель, обычно, накачивает 1,5 Атмосферы, бывают случаи, когда из-за утечки к моменту продажи это значение намного ниже. Обыкновенный автомобильный золотник закрыт декоративным колпачком (Рис.2). Откручиваем его и проверяем давление в баке (Рис.3). Чем проверять? Так как погрешность даже в 0,5 атм. существенно влияет на работу всей системы, то чем выше точность используемого для проверки манометра, тем лучше. На рынке представлены три вида таких манометров: электронные, механические автомобильные (корпус металлический) и пластиковые, идущие в комплекте с некоторыми насосами. Последние дают огромную погрешность, поэтому для ГА их лучше не использовать. Обычно они китайского происхождения, в непрочном пластиковом корпусе. На показания электронных влияют температура и заряд батареи, к тому же их стоимость довольно высока. Поэтому используем обычный автомобильный манометр, желательно прошедший поверку. Чем на меньшее значение градуирована шкала, тем лучше. Например, если шкала рассчитана на 20 атм., а измерить нужно всего 1-2, то высокой точности измерения ждать не стоит.

Рис4. Реле давления

    Меньшее количество воздуха в баке означает больший запас воды, но разброс давления при закачанном и почти опустошенном баке будет довольно велик. Тут все зависит от предпочтений. Если необходимо, чтобы давление воды в водопроводе постоянно было высоким (городским), то воздуха в баке должно быть не менее 1,5 атм. Соответственно, кто-то может решить, что напор даже в одну атмосферу для бытовых нужд вполне достаточен. В первом случае ГА запасает меньше воды, что означает частое включение подкачивающего насоса и потенциальные проблемы при отсутствии электричества, так как нет запаса воды. А во втором жертвовать приходится давлением: при заполненном баке можно принять душ с массажем, а по мере уменьшения воды удобна будет только ванна.

    Определившись с желаемым режимом работы, следует либо стравить лишний воздух, либо подкачать. Не рекомендуется уменьшать давление ниже 1 атм., а также слишком перекачивать. Недостаточное количество воздуха означает, что наполненная водой груша может локально тереться о стенки бака, постепенно повреждаясь. В то же время, избыток воздуха не позволит закачать много воды, так как существенная часть объема ГА будет занята им.

Реле давления

    Открываем крышку реле давления (Рис.4). Здесь доступна настройка верхнего и нижнего пределов срабатывания, то есть, значений давления, при которых насос будет отключаться и включаться. Две гайки и две пружины: большая (P) и малая (дельта P). Большая пружина отвечает за нижний предел или за давление включения насоса, что одно и то же. Из конструкции видно, что ее действие словно помогает воде замкнуть контакты.

    Малая позволяет выставить разницу давлений. Кстати, это говорится во всех инструкциях, однако не указывается, что является точкой отсчета. Так вот, основным является нижний предел, то есть гайка пружины «P». Пружина разницы давлений, конструктивно, сопротивляется давлению воды: она отталкивает подвижную пластину вниз, от контактов.

Практика. Вода

    После выставления нужного значения давления воздуха, подключаем ГА к системе и включаем в работу, внимательно следя за водяным манометром. На каждом ГА указаны значения рабочего и предельного давлений – их превышения недопустимо. Также в техническом паспорте к насосу указывается его напор (в метрах): 10 м соответствует 1 атмосфере. Насос должен быть вручную отключен от сети при:

• достижении рабочего давления ГА;
• достижении предельного значения напора насоса. Это просто определить – рост давления прекращается.

    Обычно, мощности насосов не позволяют накачать бак до предела, да и необходимости в этом нет, так как снижается ресурс, как насоса, так и груши. В большинстве случае значение давления отключения выбирается на 1-2 атм. выше, чем включения.

    Например, манометр показывает 3 атм., что, по мнению владельца насосной станции, достаточно для его нужд. Отключаем насос и медленно вращаем гайку «дельта P» на уменьшение, пока механизм не сработает.

    Открываем кран и сливаем воду из системы. При этом наблюдаем за манометром и значением, при котором реле включится – это давление включения насоса (нижний предел). Оно должно быть немного больше (на 0,1-0,3 атм.) давления воздуха в пустом ГА. Благодаря этому груша прослужит дольше. Вращая «P», выставляем нижний предел, снова включаем насос в сеть и ждем, пока не будет достигнуто нужное давление. Подстраиваем гайку «дельта P». Гидроаккумулятор настроен.

    Раз в 1 — 3 месяца необходимо в обязательном порядке проверять давление воздуха. Вода из бака при этом должна быть слита (отключаем насос от сети и открываем краны).

 

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90000 How to Make Your Own High Pressure Aeroponics System 90001 90002 Gathering information on HPA is very important before building your own system. We can learn a lot from other people’s mistakes and just avoid heartaches. Why go through the school of hard knocks if someone else has done it already? The problem we have is knowing what information is good advice while others are poor. So let’s talk about some of my research here. 90003 90002 First let’s set this straight that true aeroponics is high pressure.It happens to be more complicated but the most rewarding when it comes to plant growth. 90005 90003 90005 The design of HPA can be traced to 1970. However, NASA revolutionized in the 1990s by reporting it as the most efficient way to grow plants in outer space. Many studies have proven the benefits of growing plants in an aeroponic system, both on Earth and in space. 90008 Here are some of the benefits — PROS: 90009 90010 90011 It uses up to 98% less water than conventional growing methods 90012 90011 The nutrients used are 1/3 the amount needed for hydroponics and soil growing methods 90012 90011 We can plant more plants in a closer spacing 90012 90011 There is no cost for any soil 90012 90011 Some crops can produce up to four harvests annually rather than just two.90012 90021 90008 Even though aeroponics sound great there are a few downfalls — CONS: 90009 90010 90011 There are more pieces or parts to purchase compare to other growing methods 90012 90011 It uses an expensive high pressure pump 90012 90011 HPA requires close monitoring and maybe frequent maintenance, mainly clogged spray head due to salt buildup. 90012 90011 The system depends on electricity to keep it running 90012 90011 Relative short failures of the system could lead to loss of your whole crop in minutes instead of hours.90012 90021 90002 90037 Now, let’s talk about the specifics of building an HPA (High Pressure Aeroponics) system. 90038 90003 90008 There are basically two types of aeroponics 90009 90002 One that NASA produced HPA (90037 High Pressure Aeroponics 90038), and the LPA (90037 Low Pressure Aeroponics 90038) lower cost system. LPA systems are the most common used and built by DIYers. 90003 90002 LPA systems use a standard magdrive pump couple to some PVC or tubing, and a few miniature sprinkler heads.The water spray from an LPA sprinkler head has large droplets that surround the plant roots. LPAs generally run the system 24 hours and 7 days a week, continually wetting the roots. The works well, and are cheap and easy to build. However they are not as efficient as HPA systems. 90003 90002 HPA systems must operate at a high pressure, normally above 80 PSI, ideal is 100 PSI. The high pressure is used to atomize the water through a small orifice to create water droplets of 50 microns or less in diameter.One micron is one-millionth of a meter. The average diameter of human hair is 80 microns. So we are talking about a really tiny water drop. HPA also must run on a much accurate time cycle. HPAs might run 1 to 5 seconds on, and then off 3 to 5 minutes. Specific components are required in controlling the timing interval and creating the proper size mist. 90003 90008 Droplet size 90009 90002 NASA research has shown that plants are more willing to absorb nutrient water in 5 to 50 microns droplets more effectively than any other sizes.Water droplet size is crucial for sustaining aeroponic growth. Too large of a water droplet means less oxygen is available to the root system. Too fine of a water droplet, such as those generated by the ultra-sonic mister, produce excessive root hair without developing a lateral root system for sustained growth in an aeroponic system. 90003 90002 In review, HPAs require high pressure to operate properly for producing the optimal 50 micron droplet size from the misters. Also, HPAs need precise timers that are adjustable down to seconds.90003 90008 The components of our system: 90009 90002 As mentioned earlier, NASA as shown that plants ae more willing to absorb water in the 5 to 50 microns. Therefore, it is for this understanding that HPA (High Pressure Aeroponics) is more efficient than the most common Low Pressure Aeroponics system. 90003 90002 Again, to achieve the optimal conditions for plant development, it requires some primary components and tools. 90005 90037 The basic components of our HPA are as follows: 90005 90038 90003 90010 90011 High-Pressure water pump 90012 90011 Pre-Pressurize Accumulator Tank 90012 90011 Electrical-Solenoid hooked to an adjustable relay timer 90012 90011 Pressure switch 90012 90011 Mister nozzles 90012 90021 90008 High-Pressure water pump 90009 90002 High Pressure Aeroponics require a PUMP that can produce enough to pressurize the water to produce the ideal droplet size of 20 to 50 microns.These pumps are generally diaphragm pumps or reverse osmosis booster pumps. The pump must produce a steady 80 P.S.I. at your required nutrient flow. So look for a pump that can generate 100 psi or more. Some are using the Aquatec 8800 RO Booster pump. It can produce a maximum of 150 psi, so it gives you some play room. Its relatively cheap compared to other pump costs and its quieter when runnig .. The Aquatec 6800 RO Booster pump is also a good option as it can create 100 psi. However, verify you purchase it with the right regulator, and it is set for 80 to 100 psi.It’s difficult to change it later. 90005 With most moderate systems with an accumulator, this pump will work. For larger HPA systems or if you plan to expand your system down the road, buy the Shur-flow pumps. They are used in carpet cleaners and soda machines and is a dependable brand. 90003 90008 Pre-Pressurized Accumulator tank 90009 90002 These tanks are used in many homes on well water and in travel trailers (RVs) to help maintain water pressure in the pipes They. prevent the pump overworking every time water is called for at a faucet.90005 These accumulator tanks have rubber bladder that can expand and contract with water and pressure. This bladder creates two spaces in the tank; one of liquid and one of pressurized air. 90003 90002 A little physics here. You can not compress water, but you can compress air. If the accumulator tanks were filled to the very top you will find you will have no water pressure to get the water out. So for these tanks to work, there always has to be some top space in the tank to hold just air to build pressure.90003 90002 Once the pump fills it with water, the accumulator will be able to let out pre-pressurized water, using the air pressure as a driving force to move the water out when a faucet is turned on. 90003 90002 So you may be thinking why we need a tank if we have a pump that can create the water pressure for the HPA system? Why spend the time and money on an accumulator tank? 90003 90096 Well, let see why? 90097 90002 The pump is easily the most expensive part of HPAs so extending the life of the pump is going to cut down on long-term costs.So the first benefit of the tank is too reduce the fatigue and demands of the pump, less use, more pump life, it’s that simple. 90005 But more importantly, the accumulator tank serves another purpose in creating an instant and constant pressure once the solenoid opens so that the spray heads can operate for short intervals with the exact pressure, they need to produce 30 to 50 micron droplets. If the pump was directly connected to your misters instead of going through the accumulator tank, there would be a brief period of time where the pressure would be lower than 100 psi, and this slow start pressure would create droplet sizes greater than our 50 micron range .90003 90002 Examples of some accumulator tanks are Well-x-trol tanks. They are specifically designed to do exactly what we want in HPAs. Some common ones are about 2 gallons in size, however, you can use different sizes. The smaller ones save space or larger tank to make sure the pump has less of a running cycle. 90005 Somethings to consider choosing a tank size 90005 Keep in mind for larger tanks is that the larger the tank, the more «stagnant» the solution may become if you oversized it to system demands because the same solution will sit in the tank for long periods of time.90003 90002 90037 Larger tanks 90038 take more solution. So if you need to change your nutrients before the tank empties out, it will go to waste, if it can not be recycled. Once you add water to your nutrients, it becomes volatile and starts to break down. So check with the supplier and ask what’s the usable life of a mixed solution. 90003 90002 90037 Smaller tanks 90038 hold less per a given pressure and tend to drop fast if your system has heavy demands. This will force your pump to run more frequent.90003 90002 90037 *** CAUTION: 90038 Always install a pressure release valve on your accumulator tank. If the pump or pressure-switch malfunctions and does not shut-off properly, the tank could become a bomb and explode. The pressure release valve will prevent increases in pressure beyond a certain point. This is a very important safety feature! 90003 90008 An Electrical SOLENOID 90009 90002 An Electrical SOLENOID is simply the item in HPAs that will start and stop the water flow to the system when the timer turns off and on.It is an electronically operated shut-off valve. You plug in the solenoid into a relay timer circuit. The timer will control when the solenoid opens and closes, and when the plants receive their nutrients. 90005 This system is not much different than an automatic lawn sprinkler system. So if you understand your lawn system, you know what this is all about. 90003 90002 Timers for running the solenoid are best when accurate down to 1 second «on» times, and «off» times in the minutes range. One timer to use is the ART DNe Recycle Timer, but there are many other brands that can be used.I plan to build my timer based on the Aurdiono. 90003 90008 The PRESSURE SWITCH. 90009 90002 This component if what controls the pressure to the whole system. It is either purchased separately or is built into the pump as a unit. The Aquatec 8800 does not have a pressure switch so be sure to purchase it separately. 90003 90002 The pressure switch tells the pump at what pressure to turn on and at what pressure to turn off. It’s that simple. What does is sense the water pressure in the line and when the pressure is low, it turns on the electricity to the pump, as the pump is running the pressure climbs.Once the pressure reaches the set point the pressure switch turns the electricity off. The pump stops running. 90005 If you want your accumulator to be maximally pressured at 100 psi, but to be no lower than say 80 psi, then you set the pressure switch to activate the pump at 80 psi and turn off at 100 psi. Again, pretty simple. 90003 90002 The Aquatec company manufactures pressure switches made specifically for its Reverse-Osmosis pumps, and they can come pre-set to 80 psi cut-off, which is what you want to use.90003 90008 The Spray Misters 90009 90002 Atomization is achieved by pumping water through nozzles at high pressure. Nozzles come in different spray patterns and orifices. Larger nozzles and orifices reduce the chance of clogging but need pressure to operate and have high-flow rates. This is not good if we are trying to save on our nutrients and cost of operation. 90003 90002 Selecting nozzles that produce the droplet size needed will provide adequate coverage at the intended rate and pressure.For most HPA applications choose a full-cone nozzle pattern. 90003 90002 Droplet size in a given spray may vary from sub-microns to thousands of microns. These droplets are categorized in different classifications. For HPA the classification is fine-atomization a fine mist of 10 to 100 um. 90003 90002 Fixed nozzles have certain velocity or pressure ranges of effectiveness. It makes since that higher pressure nozzles have high velocities. Caution is needed here. Such velocities have the power to cut off fine root hairs in an HPA system.So stay away from these types of nozzles. 90003 90002 Use a fine-mesh filter prior to your misting nozzles to prevent clogging. 90005 Hydro-atomize water and nutrient solutions to 5-50 micron droplet range Spray. Jet nozzles with 0.025 «orifice operating at 80 to 100 psi should deliver droplets of 5 — 50 microns at a rate of 0.08 fl. oz. per second. 90003 90002 Hydro-atomize water and nutrient solutions to 5-25 micron droplets. 90005 Spray Jet with 0.016 «Orifice operating at 80 to 100 psi should deliver droplets of 5 — 25 microns at a rate of 0.04 fl. oz. per second. 90003 90008 You bet, there’s a lot to grasp 90009 90002 Now, this system may seem overwhelming to you at first. I can not tell you how many hours it took me to find enough resources to verify the items needed to make a HPAs, but it took a good deal of time over the past few months. Keep in mind that once you understand the above components though, the rest is just connecting tubing to the parts. 90003 90002 However, since I love computers and electronics, the system I build will be much more complicated than what’s needed or called for.My system will not just run as an HPA but will also be self-monitoring. Meaning my system will know the temperatures, humidity, light, and spray intervals. All of this information will get logged and store automatically and be used to tweak the system. 90003 .90000 How Does a Sewage Pump Work? 90001 90002 90003 What is a Sewage Pump? 90004 90005 90002 A sewage pump is used to transfer sewage liquids and solids from one place to another. Usually, in residential applications, sewage includes soft solids up to 2 «in diameter is pumped from a sewage basin to a sewer system or a septic tank. A sewage pump is installed at the lowest point of the sewage basin. 90005 90002 Since the pump is submerged most of the time, it is also referred to as a submersible sewage pump.Sewage pump can be automatic, manual or dual mode. A dual mode pump contains a piggyback plug, which allows the pump to be used as either manual, wherein the pump bypasses the switch and is plugged in directly into the socket or as automatic, wherein the pump is plugged in through the floating switch and works only when the switch is activated. 90005 90002 Due to a possibility of sewage overflow, it is generally not advised to use a manual sewage pump inside of a sewage basin. 90005 90002 Sewage pumps are centrifugal pumps, with special design enabling solids to pass without clogging the pump.When the pump is turned on, the motor starts to rotate the impeller, creating the pressure that pushes water into the impeller and goes into the discharge pipe. 90005 90002 The sewage pump is powered through a 10-25 ft. electric cord. Depending on the model, the voltage can be 115, 230, 460, or 575 volts. The pump housing, which contains a motor and an impeller, is made with cast iron and is built for long term use. 90005 90002 90003 Types of Sewage Pumps 90004 90005 90002 Effluent Pumps — effluent pumps are the pumps most often uses in small on-site system.They are designed to pump effluent, the effluent flowing out of a septic tank. This effluent is relatively clear liquid because the solids have developed out in the septic tank. Effluent pump can pump higher levels and more efficient than the other types of sewage pumps because these pumps do not have to handle sewage solids. 90005 90002 Solid Handling Pumps — these pumps is also called sewage ejector pumps made to pump raw sewage. Raw sewage contains too many solids for most pumps, so only solids-handling pumps should be used where raw sewage has to be pumped.90005 90002 Grinder Pumps — a grinder pump is much like a solid-handling pump. It can pump raw sewage. The difference is that the grinder pump has rotating blades, like garbage grinders that cut and grind the solids into small particles before the sewage is pumped. 90005 90002 90003 Benefits of Sewage Pumps 90004 90005 90002 Sewage pump is designed to remove water build-up from basements and crawlspaces and safely deposit it through the waste water system of a house. The operation of a sump pump is relatively simple, although their installation is more complicated.90005 90002 90003 Here the major benefits of having a sewage pump: 90004 90005 90002 • Prevent flooding damage — When heavy rains trigger a flood of water into your basement, you can quickly have 15 inches of flood water covering the floor and damaging almost everything inside , which can be especially devastating if you store valuable items in the basement. With a working sump pump, this disaster can be averted easily. 90005 90002 • Reduce the threat of mold and mildew — Continual dampness inside a basement from water in stagnant pools will contribute to the growth of mold and mildew.Not only are these both damaging to building material, but they are health problems as well. 90005 90002 • Reduce the risk of fire — The water will short-circuit the appliances in the basement, such as laundry machines, water heaters, and heating systems. So, aside from ruining these valuable appliances, water can also create a fire danger. A sump pump will keep the water from threatening equipment that could trigger household fires. 90005 90002 90003 Maintenance and repairs of this device 90004 90005 90002 • If a ground fault circuit interrupter is installed at the outlet or in the electric panel, make sure it is working.Use the test button on the unit to confirm proper ground-fault protection. 90005 90002 • Remove the cover. There are 3 common types of lids, each with slightly different removal methods. 90005 90002 • Inspect the pit for a silt or debris that might obstruct the float or clog the pump impeller or discharge tube. 90005 90002 • Make sure that it is positioned so that the float that turns it on and of moves freely and is not obstructed by the walls of the sump, discharge piping or other objects.90005 90002 • Check the drain line from the pump until it meets the air gap for any signs of corrosion, holes, damages or leaks. 90005 90002 • Check for a small 3/16 to 3/8 inch weep hole in the discharge pipe directly above it. 90005 90002 • Visually inspect all alarm mechanisms (if applicable), exposed metal parts and connections for corrosion. You may apply a silicone water repellant spray to deter corrosion. Refer to manufacturer usage instructions to apply silicone spray. 90005 90002 • Verify that there is a check valve in place on the drain line just above the pump cover.Contact a licensed plumber to add a check valve if one is not present. 90005 90002 • Check to make sure the air gap in between the interior and exterior discharge pipes should be open and clear of debris. 90005 90002 90003 Conclusion 90004 90005 90002 There are many pumping station facilities, including pumps and equipment for pumping fluids from one place to another. They are used for a variety of infrastructure systems, such as supplying water to canals, and the removal of sewage to the processing site.This station in sewage collection system also called lift station, are designed to handle raw sewage that is fed from underground pipelines. 90005 90002 Businesses can benefit from using sewage pumps as it can handle loads of water in a small amount of time. It is cost efficient if you have a sewage pump to handle those unwanted water and wet waste. 90005 90002 Learn more about how sewage pumps work and how they can help your business. 90005 90002 Source by James Roberts 90005.90000 How a Heat Pump Works | HVAC 90001 90002 An air-source heat pump uses advanced technology and the refrigeration cycle to heat and cool your home. This allows a heat pump to provide year-round indoor comfort — no matter what the season is. 90003 90004 90005 Heat Pump in Air Conditioning Mode 90006 90007 90002 When properly installed and functioning, a heat pump can help maintain cool, comfortable temperatures while reducing humidity levels inside your home. 90003 90010 90011 Warm air from the inside of your house is pulled into ductwork by a motorized fan.90012 90011 A compressor circulates refrigerant between the indoor evaporator and outdoor condensing units. 90012 90011 The warm air indoor air then travels to the air handler while refrigerant is pumped from the exterior condenser coil to the interior evaporator coil. The refrigerant absorbs the heat as it passes over the indoor air. 90012 90011 This cooled and dehumidified air is then pushed through connecting indoor ducts to air vents throughout the home, lowering the interior temperature.90012 90011 The refrigeration cycle continues again, providing a consistent method to keep you cool. 90012 90021 90004 90005 90024 Heat Pump in Heat Mode 90006 90007 90002 Heat pumps have been used for many years in locations that typically experience milder winters. However, air-source heat pump technology has advanced, enabling these systems to be used in areas with extended periods of subfreezing temperatures. 90003 90010 90011 A heat pump can switch from air condition mode to heat mode by reversing the refrigeration cycle, making the outside coil function as the evaporator and the indoor coil as the condenser.90012 90011 The refrigerant flows through a closed system of refrigeration lines between the outdoor and the indoor unit. 90012 90011 Although outdoor temperatures are cold, enough heat energy is absorbed from the outside air by the condenser coil and release inside by the evaporator coil. 90012 90011 Air from the inside of your house is pulled into ductwork by a motorized fan. 90012 90011 The refrigerant is pumped from the interior coil to the exterior coil, where it absorbs the heat from the air.90012 90011 This warmed air is then pushed through connecting ducts to air vents throughout the home, increasing the interior temperature. 90012 90011 The refrigeration cycle continues again, providing a consistent method to keep you warm. 90012 90021 90024 90004 90005 Parts of a Heat Pump 90006 90007 90002 90024 To get a better idea of ​​how your air is heated or cooled, it helps to know a little bit about the parts that make up the heat pump system. A typical air-source heat pump system is a split or two-part system that uses electricity as its power source.The system contains an outdoor unit that looks similar to an air conditioner and an indoor air handler. The heat pump works in conjunction with the air handler to distribute the warm or cool air to interior spaces. In addition to the electrical components and a fan, a heat pump system includes: 90003 90002 90005 Compressor: 90006 Moves the refrigerant through the system. Some heat pumps contain a scroll compressor. When compared to a piston compressor, scroll compressors are quieter, have a longer lifespan, and provide 10 ° to 15 ° F warmer air when in the heating mode.90003 90002 90005 Control board: 90006 Controls whether the heat pump system should be in cooling, heating or defrost mode. 90003 90002 90005 Coils: 90006 The condenser and evaporating coil heat or cool the air depending on the directional flow of refrigerant. 90003 90002 90005 Refrigerant: 90006 The substance in the refrigeration lines that circulates through the indoor and outdoor unit. 90003 90002 90005 Reversing valves: 90006 Change the flow of refrigerant, which determines if your interior space is cooled or heated.90003 90002 90005 Thermostatic expansion valves: 90006 Regulate the flow of refrigerant just like a faucet valve regulates the flow of water. 90003 90002 90005 The accumulator: 90006 A reservoir that adjusts the refrigerant charge depending on seasonal needs. 90003 90002 90005 Refrigeration lines and pipes: 90006 Connect the inside and outside equipment. 90003 90002 90005 Heat strips: 90006 An electric heat element is used for auxiliary heat. This added component is used to add additional heat on cold days or to recover from lower set back temperatures rapidly.90003 90002 90005 Ducts: 90006 Serve as air tunnels to the various spaces inside your home. 90003 90002 90005 Thermostat or control system: 90006 Sets your desired temperature 90003 90002 90003 90002 90100 90003 .90000 Pumps, Accumulators & Filters Explained 90001 90002 Why do we sell so many different pumps? What is the difference? 90003 90004 At Caravans Plus we sell a range of 12V and 24V pumps for use in Recreational Vehicles. They range from small inline or submersible pumps, to small automatic pumps, and the extremely popular automatic pumps that can operate a shower. I will explain the differences and make suggestions. 90005 90002 Voltage, fuses, and wiring 90003 90004 Most of our pumps are 12 volts with just a couple that operate on 24 volts for use in buses or trucks.This is always detailed in the specification. It is recommended to have a fuse in the wiring before any electrical device. The current draw on these pumps is usually quite low and 2.5mm to 4mm wire is in most cases very adequate. We do recommend running twin wire all the way to the pump rather than using an earth to the chassis, as using the chassis often causes problems. 90005 90002 What is meant by flow-rate? Is more always better? 90003 90004 A pump has an ability to achieve a certain flow-rate.This is expressed as litres / minute or gallons / minute. 10 litres per min will fill a 10 litre bucket in one minute. Simple right? 90013 A flow rate of 4 litres per minute will be OK for a shower. It is rare to use 10 litres per minute when using water from your tank in your RV so a pump that can achieve 10 litres per minute will suit all standard RVs. They will allow your sink to fill while someone is in the shower. 90005 90004 More is not always better, read on … 90005 90002 Auto switching and pressure rating 90003 90004 Some basic pumps just pump, and must be switched off and on by a separate switch.The Whale inline and submersible pumps fit into this category. These go direct to a straight through spout or shower rose without a tap. They are stopped by switching the pump off with a switch. 90005 90021 90021 90004 The majority of the pumps we sell are automatic and start pumping as soon as a tap is turned on. They have a pressure sensor built in and will start to pump when the pressure inside the outlet pipes is less than the cut-off pressure. This will be expressed as PSI or bar.90005 90004 We try to include both metric (bar) and imperial (PSI) versions. If we omit it, 14.5psi = 1 bar. When the pressure reaches the cut-off pressure they will stop pumping. This prevents excess pressure on all plumbing components and appliances within the plumbing system. Mains pressure in Australia should be around 5 bar but can get as high as 8 bar. 90005 90004 Some RV appliances simply can not withstand this pressure and a pressure limiting device is recommended where a hot water system is installed.At the current time the TRUMA HWS requires a pressure limiting device. 90005 90004 Other common HWS that do not require one are the SUBURBAN and ATWOOD HWS. Flow-rate and Pressure can be affected by the diameter and lengths of the pipes used. For most RVs we recommend 12mm or 1/2 inch hose as suitable. 90005 90002 Cycling of the pump 90003 90004 Cycling of the pump occurs when the pump switches off and on many times when you are having a shower. This can happen when the flow rate for the pump exceeds the rate you are using the water.If the pump is rated at 10 litres per minute and you have the tap only half on using say 5 litres per minute this will cause cycling. 90005 90004 The pump must stop until the pressure in the pipe reduces. As soon as it drops below a preset value the pump starts again. This causes the pump to switch on and off, sometimes quite quickly. There are a number of ways to reduce or eliminate this problem. 90005 90004 1) Placing an accumulator between pump and outlet 90013 2) Getting a variable speed pump 90013 3) Having a pump with built-in bypass 90005 90004 An accumulator can be thought of as a balloon.90005 90004 90044 90005 90004 Any excess flow produced by the pump that is not allowed to exit the tap, can go into the balloon. When the balloon is full, the pump will stop and the water will still flow from the tap until the balloon is empty. Then the pump starts again and repeats the sequence. 90005 90004 Depending on the size of the accumulator this can dramatically reduce the number of times the pump must stop and start, therefore the cycling will be reduced. 90005 90004 Variable speed pumps are more expensive and speed-up and slow-down to give the same pressure at the flow rate you require.While these are well establishing for the residential and industrial market, the small size pumps used in RVs tend to be less than reliable, considering the purchase price. 90005 90004 By-pass pumps. The latest generation of quality RV pumps have a bypass built into the pump. This means that when the pressure increases, some of the water that gets pumped actually goes back to the inlet side to be pumped again. So the pump keeps pumping. There is a limit to the amount that can go through the bypass or else the pump would never stop.It reduces the cycling without the need for any accumulators or electronic variable speed pumps. 90005 90004 They can still cycle at very slow flow rates, but these are the pumps Caravans Plus recommends in new RV installations and when replacing existing pumps. The most popular pump we sell has this and is shown below, it replaces the Shurflo 2088 pump that did not have the bypass feature. 90005 90021 90002 To filter or not to filter 90003 90004 Filters are recommended to prevent dirt and other debris entering your pump and causing damage to the diaphragm.Damage caused to a pump from dirt will not be covered by warranty. These should be placed on the inlet side of the pump and placed where they are readily accessible for cleaning. 90005 90021 90021 90002 Non-return valves 90003 90004 The use of non-return valves (also known as check valves) ensure that water is only able to flow one way, eliminating the chance of flow black. They are particularly useful when keeping a water line constantly primed, or water to the pump. 90005 90002 Location of pump 90003 90004 Most pumps will suck up water from the tank to the height of the pump.This will be detailed in the specifications as Dry Prime height 90070. 90071 90005 90004 A small number of inexpensive pumps need to be at or below the water level as they can not pump air to get the water flowing. As a pump wears it may not hold water in the inlet pipe when the pump stops. This makes it necessary to pump air each time until the pump is primed. You could place a non-return valve in the pipe, but that will also restrict flow. For a permanent solution you should renew the diaphragm or replace the pump.90005 90002 Installation 90003 90004 While not really a feature of any particular pump, it is important to mount the pump correctly to prevent fatigue of fittings and annoying vibrations. The mounting points should be at a solid location, not on a sheet of ply without any bracing. This is not for strength, but to prevent the mounting surface acting like the skin of a drum, vibrating in time with the pump. 90005 90004 The Shurflo range of pumps will operate in any position, however if space permits you should consider placing it horizontal to reduce pressure on the mounting points.90005 90004 It is good practice to install the pump somewhere accessible for servicing as most pumps have a built in thermal protection cut out. This area should be a well vented space to avoid accidental cut out due to premature overheating. 90005 90004 Another very important item is the connecting pipe work. This must be flexible so the vibration of the pump is not transferred through the pipe to another location that can make a noise. One common approach is to use about 300mm of flexible hose with a bend before fitting it to any straight or rigid pipework.The vibration will then get lost in the curved section if it has room to move freely. 90005 90002 Pumps running dry 90003 90004 Some pumps can run dry without damage, and this is a feature to look for in the specifications. Any pump that does not have this feature can be quickly ruined if it runs without any water to keep it cool. 90005 90002 Connections 90003 90004 Each pump will show what water connections are on the body of the pump and if any additional adapters are included.90005 90004 Our website has a unique feature that shows all the other fittings we sell that will connect to the pump inlet and outlet. These are listed as CONNECTIONS shown below the pump description. 90070 Try this feature as it ensures the parts will connect together, we guarantee it! 90071 90005 90002 The last word 90003 90004 So to conclude, when deciding which pump is best for your application remember to consider: 90005 90101 The voltage you have available 90102 90101 Do you need automatic switching or will you be using a switch? 90102 90101 What is the maximum flow rate you will need (a shower needs at least 4 lpm) 90102 90101 What is the maximum pressure your plumbing system can take? 90102 90101 What connections do you need on your pump? 90102 90101 Do not forget, you need a filter to keep dirt out of your new pump.90004 And as a last comment, noisy pumps are generally due to vibration transferring from the mounting surface or from rigid pipework transferring the vibration. 90005 90004 90115 Was this helpful? 90116 90005 90102.