Solar Hot Water Installation Process

Solar Domestic Hot Water and Solar hot water heating for homes and pools
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Solar Hot Water Installation Process

Postby Conundrum » Wed Apr 29, 2015 11:30 am

The topic has come up on the technical process of installing a SDHW system.

The following is the process to fill and commission a solar hot water system, assuming that the system is new and installed with all piping completed using compression fittings. The assumption is also made that the system is a 'Split' style system with controller installed and that there is no external heat loops. Essentially, the system is a simple loop consisting of hot water heater, pump station, expansion tank, auto-vent, heat headers and pipe.

At this point in the installation, the heat pipe tubes should NOT be installed.

1. Using a pump and bucket, or our custom fill station, connect the upper (inlet) side of the flow control valve to the output of your pump.

2. Connect a return hose to the lower (outlet) side of the flow control valve. This should flow back in to the reservoir.

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3. Set the flow control valve (in the center) to 0 using a flat screw driver.

4. Fill the reservoir with your Thermoliquatix or other suitable glycol mix.

5. Open the inlet and outlet valves.

6. Start the pump and circulate the liquid. Once the fluid is coming out of the return line into the reservoir, you will need to briefly turn the flow control valve to 3 and then back to 0 to remove any air trapped inside it.

7. Once the air is out of the system and no more air is coming out of the return line, close the return valve.

8. Allow pressure to build in the system until you reach approximately 10 pounds base + 10 pounds per story of vertical lift. This gives a loop pressure in the range of 15 - 30 psi. The pressure should not normally exceed 20 PSI when cool. When the pressure reaches the desired setting, close the input valve then shut off the pump.

9. Set the flow control valve to '2' or appropriate setting depending on your system configuration and manufacturer's recommendations.

10. Disconnect the filling station and bottle any unused glycol mix.

11. Plug in or turn on your controller.

12. Install heat pipe tubes in the header as per manufacturers instructions.

At this point, the controller should detect heat in the header and begin circulation automatically (assuming that the heat pipes are exposed to sunlight). Check the flow indication sight glass on the pump station to ensure that there is flow. Adjust the flow control on the pump if required.

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Please note, when replacing the glycol, you will need to do the following:

Drain the system and then fill the system as in steps x to y first with a mix of Tri-sodium Phosphate and water, then pure distilled water, and finally a mix of glycol and water. This should be done in the evening, preferably after dark when the headers are not hot. If you are unable to blow out the system with air, it may be necessary to mix the glycol to account for any fluid trapped in the system. For this reason it is important that only distilled water be used in the rinsing step.

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