ken2112 Posted April 10, 2020 Report Share Posted April 10, 2020 So my 2006 jacuzzi j355 has been misreading water temps by 4 to 5 degrees. So when control panel reads 104 it's only 99 to 100 degrees in hot tub. I replaced temp sensor and it still does the same thing. Is this a control panel problem then? Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted April 10, 2020 Report Share Posted April 10, 2020 How are you measuring the temperature? Could that be wrong? That spa has two sensors. Try to switch the wires in the plug, so that both wires from each sensor are in the location of the wires from the other. See if your reading changes. Quote Link to comment Share on other sites More sharing options...
ken2112 Posted April 10, 2020 Author Report Share Posted April 10, 2020 I've used 2 different thermometers and they both say hot tub is about 99 degrees. On the 2 sensors one is for the hot tub water and I thought the other one was the high output temp sensor that's in heater. Are you saying I should switch those 2? Quote Link to comment Share on other sites More sharing options...
castletonia Posted April 10, 2020 Report Share Posted April 10, 2020 I would honestly believe the hot tub 100 times out of 100 before I believed a thermometer, especially if that thermometer is an inexpensive one used for pools. If it is a quality digital thermometer, or a meat thermometer, maybe it's more believable. I don't know Jacuzzi well, but all hot tubs have two sensors, a temp sensor and a hi-limit sensor. There can be up to 2 degrees in variance but if the two sensors are not in sync, it will almost always cause an error code. Quote Link to comment Share on other sites More sharing options...
ken2112 Posted April 10, 2020 Author Report Share Posted April 10, 2020 I used a high quality digital thermometer on it. It says its 99 degrees, plus you can feel the difference when in the water between 104 and 99. There is no error code being thrown. The hot tub was always spot on with display temp and water temp till just recently. Now i can't get water to go above 100 since it thinks its at 104 and shuts off heater. Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted April 10, 2020 Report Share Posted April 10, 2020 Yes, switch the temp and high limit wires where they connect to the plug going into the board. See if the displayed temperature changes when you do so. If it does not, locate the transformer and see if it is hot to the touch. Do you have an electrical tester? Quote Link to comment Share on other sites More sharing options...
ken2112 Posted April 10, 2020 Author Report Share Posted April 10, 2020 Yes i have an electrical tester. I'll switch them later today and see what happens. Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted April 10, 2020 Report Share Posted April 10, 2020 The high limit is attached to the 3/4 loop heater top left of the spa pack. It should have a foam covering held on with a hose clamp. Check to see if the foam covering is in place and covering the probe. The temp probe going into the side wall of the spa was the wire ever spliced and joined or does the wire go uninterrupted from the probe all the way to the circuit board Quote Link to comment Share on other sites More sharing options...
ken2112 Posted April 10, 2020 Author Report Share Posted April 10, 2020 The wire goes uninterrupted from probe to circuit board. I will have to check on foam covering on hi limit probe. I was told by a tech that the high limit sensor really doesnt have anything to do with spa water temp reading, just as a shut off if heater temp gets too high. Is he wrong? Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted April 10, 2020 Report Share Posted April 10, 2020 How to test the sensor probes. 2. Temperature Incorrect or OH Another issue that comes up and is an indication of a bad temp sensor is the temperature reading becomes inaccurate or the spa is going into the OH error code. If you power the spa down and power it back up it may work for a while but will do the same thing again. You need to replace the Temp Sensor. See this link for the Temperature and High Limit Sensors and also a link to the Temperature and High Limit Sensor Diagnostic Guide and Harness Diagram: https://www.spaandpoolsource.com/sundancespastemperaturesensordiagnostic.aspx Sundance and Jacuzzi same thing Quote Link to comment Share on other sites More sharing options...
ken2112 Posted April 10, 2020 Author Report Share Posted April 10, 2020 So I already replaced the temp sensor with same results, so I guess I will replace high limit sensor as well and see if that corrects it. Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted April 10, 2020 Report Share Posted April 10, 2020 19 minutes ago, CanadianSpaTech said: Sundance and Jacuzzi same thing Not exactly. Jacuzzi bought Sundance, I happened to work at a Sundance dealer at the time, and incorporated Sundance technology into the premium line, but the controls are not always Sundance. Even number models (j350) have the sundance board, while odd numbers (j355) have a different, much simpler board that was never in a Sundance. Sensors can be easily tested with a digital ohm meter, but it is unlikely that your new sensor is out the exact amount as the old one. Take an ohm reading on each sensor with them unplugged from the board. They should be within a few hundred ohms of each other. If the sensors are plugged in the wrong terminals, you are in fact getting your temp reading from the high limit sensor, which you did not replace. This could have happened at the factory and been that way all along. 2 hours ago, castletonia said: There can be up to 2 degrees in variance but if the two sensors are not in sync, it will almost always cause an error code. On a watkins, where both sensors are mounted to the heater, one on the inlet the other on the outlet, there may be an error triggered by 2 degrees difference. When the temp probe is in the spa wall and the hi-limit at the heater there may be a higher acceptable variance between the two sensors. I am not sure of the allowed variance on a Jacuzzi board, so can't assume it would trigger an error for 4 or 5 degrees difference. Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted April 10, 2020 Report Share Posted April 10, 2020 Good to know Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.