Introduction To
Solar Hot Water Heating Panels

DIY Solar Hot Water Heating Panels

Solar Hot Water Panel Installation Instructions

Solar Hot Water panels should only be installed by trained personnel. If you have not been trained to fit solar panels, . These instructions are designed as a reference and not as a substitute for proper training.

Process Install Solar Hot Water panel FRAME/manifold on roof (without tubes) Replace existing Cylinder with Solar twin-coil cylinder Install pipework/accessories Install Electrical works Fill the system and commission Install tubes Check function of system, re-bleed air if necessary

Sometimes it may be easier to install the system in a different order. The actual procedure order is not critical, however, it is important not to fit the tubes until the all plumbing and electrics are installed, as the tubes can get very hot without any water circulation

Install Solar Hot Water panel FRAME/manifold on roof (without tubes) The panel should be attached to the roof using the roof mounting kit, with the header at top of the frame. The panel may be mounted at angles of 15-90º. After careful measurement, the roof mounting straps should be attached to the roof. Four straps are provided for the 20tube panel and six for the 30tube pane. These should be attached to provide fixings to top and bottom of each vertical rail. The mounting straps are designed to be installed without the need to remove any tiles, or drill holes through the tiles, thus reducing the chances of breakage or water ingress.

Once the panel is mounted on the roof, you will need to drill one hole through the roof at either end of the manifold, to allow the pipework to pass perpendicular through the roofing structure. We recommend the use of diamond-tip core drills or standard masonary bits, and drilling steadily without hammer-action. The panel has 22mm pipe terminations, and a 22mm elbow should be fitted to both of these. A reducing olive should be fitted into the other end of the Elbows, to allow 15mm pipework to be inserted directly into the elbow. (It is only necessary to run the pipework in 22mm for very large systems eg large swimming pools). This necessitates the drilling of 17mm hole through the roof, which will leave 1mm clearance around the pipe. This gap should be sealed using builders’ silicone sealant, ensuring that it is pushed right down into the hole as well as smeared around the pipe, to ensure a good seal. Armaflex HT insulation should be applied to the pipe and elbow to ensure good insulation of the exterior pipework.

Replace Cylinder with Solar twin-coil cylinder

This part of the process can take considerable effort, depending on how difficult it is to access the existing cylinder. The process will differ depending on the location. In short, the existing cylinder should be replaced with a twin coil solar cylinder, using the upper coil for the boiler and the lower coil for solar. The other cylinder connections should be connected in traditional fashion, all have compression fittings for ease of installation.

Install pipework/accessories

Before installing the pipework, it is important that the location for the solar panel has been established. The ‘flow’ from the solar panel should be connected to the top of the solar coil and the ‘return’ should be connected to the bottom of the solar coil. The solar pipework should be carried out in 15mm. All joints in the flow and return pipework should be made with soldered fittings (using unleaded solder) or with compression fittings. Piperun lengths should be minimised to prevent heatlosses, and all pipework should be fixed at regular intervals, and insulated with High Temperature pipe insulation. Under no circumstances should standard pipe insulation be used, as it will melt during sunny periods. The pump should be installed on the return line, usually close to the cylinder, utilising isolation valves, so that the pump can easily be removed for maintenance, should it be required. An anti-syphon valve should also be installed in the system, on the return line to prevent heatloss through thermo-syphoning to the panel at night. It is not necessary to fit an antisyphon valve if the panel is LOWER than the cylinder. In most cases, it will be necessary, or at least advisable to fit a pressurised system to the solar loop, such as the pressurised system kit. This should be fitted to the return line near to the cylinder. Under no circumstances should the pressure relief valve be fitted near to the solar panel manifold. If a pressurised system kit is NOT fitted, then the solar loop must be installed with a vented system kit – which requires a header tank to be mounted at the highest point in the system. Do NOT insulate the body of the pump, as this can cause premature failure.

Install Electrical works Follow the wiring instructions in the manual supplied with the controller. If the solar controller has a temperature display, it should be mounted in a prominent place where the display can be seen. If necessary the temperature probe wires can be extended using 0.75mm2 cross-section cable up to 50m away from the controller. The controller should draw power from a fused spur with 3A fuse. The power supply cable for the pump should be connected to the relay output of the controller as described in the controller manual.

Fill the system and commission Before filling the system with antifreeze, the system should be flushed several times with water to remove residual flux and debris. The system should then be filled with a 40% dilution of Non-Toxic Solar Antifreeze. The antifreeze should be pre-diluted and poured into the Filling Kit. This links to the filling loop supplied with the Pressurised System kit. The system can then be pressurised up to the operating pressure of 1bar. It is necessary to loosen one of the compression fittings on the panel manifold to allow the trapped air to escape. If you over-pressurise the system, fluid can be bled out of the pressure relief valve by turning it, which will temporarily open up the valve.

Install tubes

Before installing tubes check that the tips of each tube are silver. If any are white, then the vacuum seal has been damaged and they should be replaced. If it is necessary to replace a tube, please retain the heatpipe and internals which can be transferred to the replacement tube. Once all of the plumbing and electrical systems have been installed, the system is bled and everything is operational, the tubes can be installed.

Before installing the tubes, the copper tip of the heatpipe should be liberally coated with thermal contact grease – which is supplied with the header – before inserting into the header. Each tube should have a rubber cap fitted to the lower end of the tube, and, once the tip has been fully inserted into the manifold, the stainless steel jubilee clip on the bottom rail should be tightened around the outside of the rubber cap to retain the tube. Be careful not to overtighted!! Do not use a socket wrench for this job. You should use a screwdriver, and should rotate the tube whilst tightening the jubilee clip. As soon as resistance is felt do not tighten any further. Over-tightening will result in fracture of the bottom of the tube in colder conditions – be especially careful if installing tubes in warm weather.

Check function of system, re-bleed air if necessary

Once the tubes are installed, it should be possible to watch the panel temperature start to increase on the display. It will be often be necessary to circulate the water to shift trapped air bubbles, and it is usually necessary to bleed the system again after it has heated up, as some gas can be generated during this process. Once the system is up and running, you should begin to enjoy free solar-heated hot water for many years to come.