I'm having a problem with my hot tub heater. It's the exact opposite of what most people have (heater not working)- it is actually working TOO well. Let me explain. About a month ago, my son was complaining that the hot tub was overly hot. When I checked it, it felt pretty hot to me too. So I put the pool thermometer in it. To my surprise, it read 118 degrees! I got another thermometer to double-check the reading, and got 117 degrees. After doing some research, I determined I should probably call a technician to handle this problem. The technician came out, looked things over, and told me it was either the High Limit Switch, or the Thermistor. He pointed out both switches (I already knew where they were from looking at the parts schematic), and explained how they could be changed. He said I could do it myself if I was handy, or I could pay him $150 to come back and take care of this 10 minute job. I opted to do it myself. So I ordered the parts and changed them out. The result? I am having the same problem. When I set the heater temp to 100 degrees, the burner turns on and it heats up the water until it reads 100 degrees, as requested on the display. The problem is, what the heater thinks is 100 degrees is actually around 115. I double-checked this by turning the requested temp down to 85 degrees and running the heater. The result is water that is actually 100 degrees, although I am requesting 85 degrees. The system works as advertised, except for the fact that its temperature calibration is off by 15 degrees. Anyone have any ideas on this one? I've already changed out the thermistor probe, which seems like the most likely culprit in this situation. My next step is probably changing out the control board. I don't want to do that if I don't have to, as it is a $400 part. Thank you in advance for any advice/solutions you can offer.
Your problem sounds like a faulty control board. I replaced the high limit switch, the thermistor, and the control board in an attempt to resolve an erratic temperature reading (plus and minus 1 degree).
It caused the heater to turn off and on constantly when the target temp was reached. My successful solution involved replacement of the two brown wires that connect the control board to the thermistor. The wires were ok but the connector(s) were not. The thermistor output is very small and the contact must be solid in order for the control board and thermistor to communicate. As for the price of the board...it is closer to $300. The one I purchased (and didn't need) was about $275. Seems like you have done everything except change out the board. It doesn't sound like your problem involves corroded wires. Good luck
SOURCE: Pool Heater Mis-reading Temp.
Your temp sensors are on the heater, a small tube that slides into the water manifold, usually on the left side. On the remote it will be in one of the pipes coming from the pump or the filter. If it is after the heater you should move it to between the filter and heater. It will be a tube that is in the pipe with a stanless steel clamp holding it in place.
To find out wich one it is you will need to remove the remote from the system by takeing the wires that go to it from the wireing inside the heater and wire nuting the wires in the heater together. If the heater runs normal then it is the sensor for the remote if not it is the sensor for the heater. Let me know how you do and if need be we can get a little more specfic for your system. good luck.
SOURCE: have pentair easy touch controls just installed
Go to "calibrate" on your new unit and lower the spa "set at " temp a little
I have had the same problem with my '400' since it was new. I contacted the manufacturer and got the run around. I have been trying to get this resolved and now, a year and a half later, have decided to buy a different heater. Anyone want to buy a hardly used Pentair 400? [email protected]
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