Solar Thermal Home Heating Systems

I Am Installing A Drainback Solar Thermal System How Do I Facilitate Proper Drainback?

I am installing a drainback solar thermal system how do I facilitate proper drainback?

In order for your system to "drainback" when the pump shuts off your collectors and piping must be sloped at 1/4" per 12" of run. Be aware that visually your collectors will not be parallel with your roof ridge.

How can I connect an air compressor to my pump station to pressure test my solar thermal system for leaks?

How can I connect an air compressor to my pump station to pressure test my solar thermal system for leaks? Our pump station’s fill valve has GHT hose threads on the outside. You can easily make an adaptor using the following three fittings, which can be purchased at your local hardware store or plumbing supply.

Schrader valve x ¼” male NPT
Reducing Bushing, ½” NPT Male x ¼” NPT Female
Hose fitting, ½” NPT male x ¾” swivel GHT female

Use Teflon tape on the NPT threads of the Schrader valve and bushing in constructing the adaptor. When attaching the adaptor to the pump station, be sure to use two tools: one to hold the fill valve in place, and one to tighten the adaptor. That way, you won’t create leaks in the pump station itself while testing.

How should I test my solar thermal system for leaks?

How should I test my solar thermal system for leaks? After a solar thermal system has been installed, it should be tested for leaks before it is charged with heat transfer fluid. Leak testing should be done with air pressure. Air pressure can detect even small leaks that would be difficult to detect with liquid, because the liquid would evaporate as it leaked. Even tiny leaks are critical, because loss of fluid over time would change the system operating conditions and decrease performance. For more information, watch our webinar on air pressure testing.

My sensor cable is only 4 feet long. How do I wire it from the controller all the way to the collectors?

My sensor cable is only 4 feet long. How do I wire it from the controller all the way to the collectors? First off, when wiring to the collectors, make sure you use the high temp sensor (usually black or red). One end of the sensor cable has the sensor, which needs to be at the hot end of the collector array, and the other end has crimped wires that fit easily and securely into controller slots. So, the best thing to do is cut the sensor cable in half, and use each half where it is meant to be used. How do you bridge the gap? Well, SunMaxx pre-insulated line set (corrugated stainless steel pipe) has a 2-strand wire cable embedded inside it just for that purpose. Use the wire in the return line from the collectors to connect the two halves of your sensor. Wire connections should be soldered and shrink wrapped. The SunMaxx “Sensor to Wire Connections” installation guide shows the step-by-step process.