I have a "Thermia" geothermal unit installed in our house in 1995. This unit has hot water on demand option. During this time it performed satisfactory. At the beginning of July 2010 I had a "LOW PRESSURE FAULT" light on the system. I contacted a repairman and he changed a "by pass valve". After a few days I started having a "HIGH PRESSURE FAULT" light, and would not heat water anymore. The contractor that I did call did not understand my system very well and told me to contact some other contractor that was familiar with my system. I called one recommended by a friend, he came worked on the system for about 2 hours, could not recreate the problem, told me to clean the coil, and that otherwise everything was fine and left. Between the two contractors it cost me $1200.00. Two day later the problem came back again, so far he has not been able to come back. I can reset it, it runs ok for a few days then I get the light again. I hope some one can help me with first finding a good, reliable, expert service company in my area, Caledon Ontario, Canada. And second on how and what product to use, to clean the coil. It is very difficult to get at the coil.
faltobelli, I'm not familiar with the system either, but there are common threads in pressure problems. Among them are air flow, water flow, freon charge, undesirable temp on entering/leaving water or air temp problems. It is interesting that the pressure sympton changed from low to high after initial repairs. Is system open or closed loop? I would suggest to repairman 1 that professing ignorance of the system after charging you for a repair is not satisfactory and he should man-up to at least a partial refund. Good luck, j
Just had a thought of common thread between both low and high pressure trips. If you are cooling your home as well as making DHW, gpm is suspect. Check for proper loop water flow through heat exchanger. (if you are not cooling the house disregard) j
