I just replaced my 5 yo heat exchanger because it was leaking. At the same time I replaced the bypass valve and the thermal regulator. Everything is operating normally except for this annoying whining sound that starts shortly after ignition and stops when the burner shuts off. If I run with the thermal regulator removed it is quiet. So I presume its a water flow issue involving the thermal regulator. I have verified that the bypass valve is installed correctly and not jammed. I have tested the thermal regulator. It starts opening at 120 degrees, but is not completely open till about 140 degrees. Is that correct, or should it be fully open at 120? Could the noise be because the regulator is not opening fully? Thanks, for any help.
Mastertemp 200 heater whining sound
- Thread starter Artichoke
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Pool Clown
In The Industry
Confirm that he "bulb" of the therm reg is facing away from the spring assembly. Thats all i got. @JamesW ?
Pentair Mastertemp 200 - Loud Heater Whine
Hi all, This is my first post but I've been reading these forums for about a month now. We own a pool that was not taken care of very well for several years and have been on a mission to fix this heater. It all started with an E05 error that required us to replace the stack flue sensor, control...
www.troublefreepool.com
Here's another one with the same issue.
Do you have video of the startup and noise?
LOL for the thought that the thermostat was installed backwards. Wish it was that easy. It is installed correctly.
The two videos sound very similar to what mine sounds like. Thanks for the pointer to that thread. I'll try taking the manifold apart (again), and make double sure there is no obstruction or other explanation for water flow noise. Every thing else in my system is the same as it has been for 8 years, so must be something with the new heat exchanger install. I did change from copper to copper nickle, but I can't imagine why that would make a difference.
The two videos sound very similar to what mine sounds like. Thanks for the pointer to that thread. I'll try taking the manifold apart (again), and make double sure there is no obstruction or other explanation for water flow noise. Every thing else in my system is the same as it has been for 8 years, so must be something with the new heat exchanger install. I did change from copper to copper nickle, but I can't imagine why that would make a difference.
Remove the thermal regulator to see if the noise goes away.
If it does, I would try a new thermal regulator.
Also check the internal bypass to make sure that it's functioning correctly.
If you look in the inlet, you should be able to see the spring portion.
If you look in the hole where the thermal regulator goes, you should be able to see the plunger disc against the upper wall.
If it does, I would try a new thermal regulator.
Also check the internal bypass to make sure that it's functioning correctly.
If you look in the inlet, you should be able to see the spring portion.
If you look in the hole where the thermal regulator goes, you should be able to see the plunger disc against the upper wall.
Noise goes away with thermal regulator removed. Tested thermal regulatory, started opening at 120, fully opened at 135-140. Got another one anyway, same problem. Already checked the bypass valve, but will check it again when I pull the manifold. I am planning to check the heat exchanger for blockage. It's new, but I'm running out of things to try.
I suspect that the thermal regulator is probably opening just a crack and the water flow through the crack is causing the noise. I'm not sure why it's happening specifically on your system.
If something is keeping it from getting hot enough, that would explain it. Is there any way to get the temp of water at the location of the HLS? I assume the HLS is just a trip switch and does not read temp.
I'm not sure, but I think that the thermistor is probably the same thread as the high limit. You could screw in a thermistor and read the resistance and translate the resistance into temperature following a 10k chart.
You would have to jump the high limit wires, but shut off the heater if the resistance drops below 2,800 ohms as that corresponds to 135 degrees.
Correct. The high limit switch (HLS), which opens if the heat exchanger outlet temperature goes above 135° F (57° C).
The thermal regulator should be fully open at 120 degrees. If it's not, I would replace it.
Also, check the stack flue temperature by pressing and holding the Pool On button until the display switches to the stack flue temperature.
Here is what the normal exhaust temperature should be:
- Below 250 degrees...very low
- 250 to 290 ..................low
- 290 to 350.................acceptable
- 350 to 480 ..................high
- Above 480...................error/shutdown.
Pentair MasterTemp Heaters - Further Reading
www.troublefreepool.com
The thermal regulator should be fully open at 120 degrees. If it's not, I would replace it.
Hmmm. I have two new thermal regulators from two different suppliers. Both came in sealed Pentair branded bags, so at least not obviously counterfeit. Both start to open and 120 and don't fully open till 135-140. Are you sure it should be fully open at 120? If that is the case, it would certainly explain what I am seeing. Just bad luck that I got two bad thermal regulators?
Hmmm. I have two new thermal regulators from two different suppliers. Both came in sealed Pentair branded bags, so at least not obviously counterfeit. Both start to open and 120 and don't fully open till 135-140. Are you sure it should be fully open at 120? If that is the case, it would certainly explain what I am seeing. Just bad luck that I got two bad thermal regulators?
The opening temperature should be stamped on the thermal regulator. See picture where it's stamped 120F.
Also, from the manual:
The high limit opens at 135, so that indicates that the water temperature should never get that hot.
If the thermal regulator is not fully open at 125 degrees, I would replace it.
Also, from the manual:
The high limit opens at 135, so that indicates that the water temperature should never get that hot.
If the thermal regulator is not fully open at 125 degrees, I would replace it.
Last edited:
Pool Clown
In The Industry