In addition to a professional design and installation of a solar thermal system is the professional commissioning a must condition for a smooth operation. Series of mistakes can reduce the solar yield, may lead to the system failure and will result in costly damage.
Avoid by all means:
Wrong concentration of the heat-transfer fluid
Incorrect pressure in expansion tank bladder
Incorrect system pressure
Inadequate corrosion protection of the heat transfer fluid
Low pH value of the heat transfer fluid
Wrong Settings/Programming of the Controller
Contamination of the heat transfer fluid (dirt etc)
Defective check valves
Propylene Glycol is an effective antifreeze agent. However, when improperly added to the system can be too weak to be effective and allow freeze-ups, or to strong so as to create complications of corrosion, and contamination of the potable water supply.
At stagnation temperatures glycol breaks down into glycolic and oxalic acid, which will immediately attack most metals including steel, brass and copper. Different buffer agents are added to the glycol to prevent acid formation. These, again, are active chemicals which are rapidly used in the system. By systems troubled with stagnation annual fluid replacement is absolute must and, even then, is not a guaranty against corrosion. Glycol solutions may dissolve some seals and gaskets. Leaking glycol on the roof can also dissolve asphalt tiles or other roofing materials.
Checking the freezing point temperature of the glycol-water mixture
after installation is very important especially if the hydraulic pressure test was done with pure water.
The glycol concentration is affecting the thermal conductivity (heat removal from absorber), viscosity (pump head - energy consumption) and specific heat ratio. Knowing the actual concentration of your glycol will help to determine the levels of protection from Burst and Freeze.
Want to be sure your glycol mix is ok? Solarnetix's own Solarcheck Toolkit will ensure you have the right tools for the job - every time. Used in conjunction with our handheld Refractometer you can ensure you are prepared for almost any testing or maintenance situation.
Solarcheck Toolkit for Testing Thermal Solar Systems consists of:
- Precision Pressure Gauge
- Compass
- Circuit tester
- Infrared thermometer
- Digital pH-tester
- Optical Refractometer
- Inspection sticker (12 pieces)
- Glycol Reference sticker (12 pieces)
- Measuring glass
- Air vent key
- Syringe
- Calibration screwdriver
For that reason they are looking for an installer that they can rely on. 
