More About Solar Panel Water Heating Installation

Our solar water heating pumping station is protected by British Design Rights.

We can offer a good price for our solar water heating installations because we are a small operation with low overheads to pay.

Our Chief Installer, Paul Brooks who overseas every fitting is a graduate in mechanical engineering and designed our unique pumping station that are pre fabricated and tested off site to ensure a reliable and quick installation.

This is plumbed between the return side of the manifold of the solar collector array on the roof and the secondary solar coil on your new hot water cylinder the flow side of the solar collector array is connected directly to the remaining outlet on the secondary solar coil, (forming a loop). Other connections to the pumping station are the pressure relief valve connecting to a pipe and going to the exterior of the property the expansion vessel to allow for expansion and contraction over the summer and winter months and the and pump that allows you to initially prime the system and to maintain the system over time.

We have fitted a hand pump so that we do not have to connect it to the mains system to prime the solar water heating loop, from the roof to the coil in the water cylinder. This has distinct advantages by allowing you to mount the solar heating pumping station anywhere and saves you on the cost of copper plumbing also you really want to prime the solar water heating loop with a high heat transfer fluid we use one imported from Germany which is glycol based. The temperatures reached by the solar circuit fluid can reach well above one hundred and forty Celsius which will cause crystallisation in water which will affect the reliability of the solar water heating components in the long run.

After the initial priming of the solar water heating circuit you will need to allow some air out that is drawn in through the high heat transfer tank and hose pipe. The air will naturally collect as it passes under the float chamber that is situated above the pressure gauge. When this happens use the easy bleed system by opening the tap to release the air and then do a few more pumps on the hand pump to raise the pressure. After two weeks gases will be released from the high heat transfer fluid as the fluid heats up and cools down during normal operation. Once again as the fluid flows under the float chamber the gas will start collecting in it and so you will need to use the easy bleed system once again and to push the hand pump in two or three times to raise the pressure.

The only component doing any real mechanical work within the solar water heating circuit is the Grunfoss pump that will turn on intermittently when it see a temperature difference of six degrees between the solar collector array manifold and the bottom of your new hot water cylinder where you solar coil is situated. It is doing far less work than it would do in a central heating boiler as it is not constantly on and it does not have to run at higher pressures (there are valves in a central heating circuit the will restrict flow but there are non in the solar water heating circuit). Anyway, in the unlikely event that the Grunfoss pump does fail, (the pump is mounted at the bottom of the casting on the pumping station), and you have to replace it just attach the hose pipe to the drain cock at the bottom of your secondary coil on your hot water cylinder. Then open the drain cock and drain the high heat transfer fluid from the solar hot water heating circuit back into its original container and then close the drain cock. Then replace the Grunfoss pump on the pumping station and connect the hose pipe to the base of the hand pump and open the taps and then re prime the solar water heating circuit using the hand pump and release the air collected from the re priming process and release the absorbed gases (released from high heat transfer fluid over the first weeks) using the chamber tap and auto vent valve mounted above the pressure gauge.

On the first day of the installation you will need to swap the hot water cylinder for the new hot water cylinder with the secondary coil for the solar water heating system. The reason we fit a new hot water cylinder with its own dedicated heating coil with every install is because this is the only way to install a solar water heating system properly. The high heat transfer fluid has to heat the coldest part of the tank which will be the bottom of the cylinder due to convection (cold water sinks to the bottom of the tank).

Some systems fit a solar panel without a new tank and purely feed the heated water into the top of the tank where it is already hot!

Turn off the water supply at the mains. If it is difficult to turn off the water mains because it is old you can tie off the ball cocks on the header tanks (big cistern in the attic) for the hot water cylinder and the central heating circuit (little cistern in the attic) and turn off the water supply from the header tank to the hot water cylinder and switch off the boiler and any emersion heaters and turn on the cold taps. Attach a hose pipe to the drain cocks on the central heating circuit using a jubilee clip and run the pipe out side or into the sink or bath. The drain cock should be found on the downstairs radiator piping although sometime they don’t exist at all, if there is no drain cock you will need to drain the whole circuit and fit a new drain cock. Open the bleed nipples on the top of the radiators (if the hot water cylinder is on the first floor, only drain down the first floor radiators) this will aid draining. You will drain down the existing hot water cylinder by attaching a hose pipe to the hot water cylinder drain cock using a jubilee clip and run the pipe outside or into a bath or shower this can take some time to drain down, though you could insert a pump into the hose pipe to speed the process up.

Disconnect the central heating and hot water pipes from the hot water cylinder noting the flow and return directions from the boiler and then remove the hot water cylinder being care fully not to spill any of the central heating fluid from the hot water cylinder as this can stain carpets badly. Before fitting the new hot water cylinder check that the platform that the cylinder will be put on is strong enough and put a new piece of plywood down to create a level platform to place the new cylinder on. Reconnect the piping whilst trying not to create any air traps in the new pipe work and close the drain cocks on both the hot water cylinder and central heating circuit and close the bleed nipples on the central heating circuit turn the mains and refill the central heating circuit header tank first by untying the ball cock first (small cistern in the attic) so that if you do find a leak in the central heating circuit you will only have to drain down the central heating circuit and not the hot water cylinder which takes a long time.

Once you are happy that there are no leaks in the radiator circuit you can turn on the water supply between the header tank and the hot water cylinder and then untie the ball cock to the large header tank and refill the hot water cylinder and then go and re bleed the radiators.

Connecting the hot water cylinder to the solar collector

After installing the hot water cylinder you should have two pipes on the hot water cylinder left remaining. One of these pipes will be connected directly to the flow side of the solar collector and the other pipe will be connected to the return side of the solar collector via our piping station.

Mount our pumping station (usually the airing cupboard) in a suitable position to give flowing pipe work between the cylinder and solar collector using the 6×50mm screws. Then mount the expansion vessel near to the pumping station and connect to the casting on the manifold.

Connect the flow side of the solar collector (end with the sensor in) to the top connection on your solar water heating coil on your hot water cylinder using compression couplers and reducing elbows. You must use compression couplers on the flow side of the array because the high heat transfer fluid can reach temperatures that will melt solder. Then connect the bottom of the pumping station (under the Grunfoss pump) to the bottom pipe of the solar water heating coil and install the tee and drain cock at the lowest point. Then to complete the solar water heating circuit you must connect a pipe from the pumping station to the return side of the solar collector in the piece of pipe you will fit a non return valve at the pumping station with the flow headed towards the solar water heating panel. Once again you must use compression fittings on this section when you are within two metres of the solar collector because of the high temperatures.

Then get the high temperature lagging for the flow and return pipes from the solar collector and pour a little talc down the inside of the lagging. Then run the lagging down the pipe before making your final connections. This saves you from having to slit the lagging and helps retain heat and makes for a much smarter install. Use saddle clamps to mount the lagged pipes and use a short section of lagging to pack out the pipe from behind where you mount the saddle clamps.

Then run the pressure relief pump from the pumping station ensuring that the first two metres are done in copper the rest can be done in plastic. This pipe can be run to the outside of the house or into the small central heating header tank.

A vent pipe will come off the solar collector manifold and back into the loft where it will have a 8mmm stop end mounted on it. Open the three taps on then pumping station and prime the solar water heating circuit to 1.8 bar using the hand pump hose pipe and high heat transfer fluid. Then loosen the 8mm stop end in the loft to let any air out re tighten and pump a few more times. Heck for any leaks on the solar water heating circuit and then reduce the pressure to between 0.5 and 0.8 bar using the drain cock on the bottom of the solar water heating coil on the hot water tank using the hose pipe to drain the fluid back into the tank for the fluid.

There are two sensors pockets in the hot water cylinder and one in the flow side of the solar collector. Connect the solar collector array to (S1) on the Resol unit mounted on the pumping station you can extend the wire if required using 2 core wire and a 5Amp junction box. Fit the sensors (S2) in the lower sensor pocket and (S3) in the upper sensor pocket on hot water cylinder using the nut and gland and plug the unit into the 240volt mains supply and turn on the Resol unit and check the readings for all of the sensors. If you need a socket installed contact a qualified electrician.

Furthermore, all of our tanks are custom made so if you need one coil just for the solar and extra emersion heaters at the base of the tank for cheap rate electricity or two coils or even three coils for maybe a back boiler, oil, and the solar its not a problem. The insulation on the tank is twice the standard at fifty millimetres and all connections are at surface level so you do not have to cut away the insulation and all vertically aligned so that you can run the piping down one side of the airing cupboard and then push the water tank into the back of the airing cupboard to save space. You can then connect the piping horizontally across the front of the tank.

The pumping station also allows you to easily monitor and maintain the solar water heating circuit and in the unlikely event of you having to change a component and bleed the system it can all be done from inside the house via the pumping station and the air bleed point that we have mounted in the loft (bleed points are mounted on the roof normally making it impossible to change or adapt the system without hiring expensive scaffolding to get up on the roof and re bleed the system). The pumping station also has the resol unit (that controls the pump and in turn regulates the water temperature) pump and all fixture and fittings mounted on it. This allows you to route all the plumbing via one point and makes the circuit simpler to understand.. The pumping station also has a hand pump mounted on it to prime the independent solar circuit with which means that you will not have to plumb into the mains to prime the circuit.

We fit a brand new water heating tank with its own dedicated heating coil with every install this is the only way to install a solar water heating system properly because you need to heat the coldest part of the tank which will be the bottom of the tank due to convection (cold water sinks to the bottom of the tank). Why would you want to fit a solar panel without a new tank and purely feed the heated water into the top of the tank where it is already hot? Furthermore all of our tanks are custom made so if you need one coil just for the solar and extra emersion heaters at the base of the tank for cheap rate electricity or two colis or even three coils for maybe a back boiler, oil, and the solar its not a problem. The insulation on the tank is twice the standard at fifty millimetres and all connections are at surface lvel so you do not have to cut away the insulation and all vertically aligned so that you can run the piping down one side of the airing cupboard and then push the water tank into the back of the airing cupboard to save space. You can then connect the piping horizontally across the front of the tank.

We only only use the high quality pegler compression fittings which maybe more expensive for us but will ensure a much more robust installation with no leaks

We have experience in fitting east west solar panel installations where you do not have a south facing roof. In this situation one solar panel is fitted to the east facing roof and one panel is fitted the west facing roof. The controller will allow the hot water tank to be heated from the east facing solar panel in the morning up until mid day and then automatically switch to the best facing solar panel to heat the water tank. You can also fit a larger solar panel on the east facing roof to just capture the solar radiation up until mid day the solar panel will have to be twenty percent larger than a south facing panel but this is not the preferred method as we believe that you will lose around ten percent performance.

We can also connect an extra coil to your back boiler in your wood burner or connect up to diesel boilers.