mah48092

Get a sensor. I am so thankful I found this forum and in particular this thread. I have been getting similar error codes (120 and now 121) on my unit for the past couple of weeks. Following the technician repair manual that was posted (thank you very much), I believe I have a bad cell. I have DC voltages of 33.6 volts from the control board to the cell and my reading across test point 4 and 5 is only 27 mVolts. I just hate spending $500 on a new cell if that really isn't the problem. What does everyone think? Thanks for any help and advice.

Mah48092, thanks so much for the reply. I live in Michigan too so it's good to hear that the Starite is working for you. Can I ask why you replaced your other Maxitherm and how old was it when you had to replace it? Odd that you can run the heater without a thermostat. I would think you'd have to have one. My maxitherm was ten years old and the burner efficiency was not very good. Also, every spring when I start it up I have to take the gas valve apart to clean it. Over the winter it seizes up - that started about 5 or 6 years ago. In my opinion it is in a poor location and the orientation leaves much to be desired.

The heater turns on and off just fine by comparing the inlet temperature to the setting I dial in. As far as I can tell the thermostat has no bearing on whether the burner shuts down or not. I have seen no issues with running without the stat for the past month of operation.

I live in Michigan and installed a sta-rite 400 nickel-cupro heater earlier this year. It is nowhere near as loud as the one in the video. It is noisier than the 400,000 BTU maxi-therm that I used to have, but it is no louder than than my circulation pump and certainly quieter than my spa air injector. Some additional information, I did have a problem with restricted water flow due to too many bends in the PVC pipe which led to noise in the inlet pipe when the heater fired up. I called a service technician and he simply removed the thermostat from the unit and the noise disappeared. I was concerned about voiding my warrantee and he stated very clearly running the heater without the thermostat installed in the unit was fine. I have used the heater extensively this spring, remember I live in Michigan, and am very pleased with the performance. My water temperature rise across the heater is 8 degrees as opposed to 4 degrees with my old one. Hope this was useful.

I am so thankful I found this forum and in particular this thread. I have been getting similar error codes (120 and now 121) on my unit for the past couple of weeks. Following the technician repair manual that was posted (thank you very much), I believe I have a bad cell. I have DC voltages of 33.6 volts from the control board to the cell and my reading across test point 4 and 5 is only 27 mVolts. I just hate spending $500 on a new cell if that really isn't the problem. What does everyone think? Thanks for any help and advice.