Pentair MasterTemp 250 runs for couple minutes then triggers Service Heater light

ColoradoKid

Member
Feb 20, 2019
6
Boulder, CO
It starts fine, runs for 2-3 minutes then triggers the Service Heater. I took the front panel off to see the LEDs on the board and I see nothing that is on. What would tigger the Service light if no LEDs are triggered?

If I turn it off and turn it back on, it will run again for the 2-3 minutes then trigger.

The unit is only several months old. It's already leaked twice and had to be fixed under warranty. Since the last leak, it's run great for about 2 weeks.
 

JamesW

TFP Expert
Mar 2, 2011
16,072
What does the display show as the heater starts and begins to run?

Why did it leak?

Do you have a picture of the system?

Check the thermal regulator.


Can you post a video of the heater starting and running?
 
Last edited:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
8,879
Northern NJ
It starts fine, runs for 2-3 minutes then triggers the Service Heater. I took the front panel off to see the LEDs on the board and I see nothing that is on. What would tigger the Service light if no LEDs are triggered?
Manual is here --> http://www.pentairpoolme.com/uploads/document/file/554/Manual_MasterTemp.pdf

See Troubleshooting beginning on Page 38.

I think it leads you to:

Observe for delayed or rough ignition, poor combustion, premature extinction of flame, evidence of boiling, or operation of any diagnostic LED.


Basically you need to observe the heater during its shutdown and see if you can spot what is going on.
 

ColoradoKid

Member
Feb 20, 2019
6
Boulder, CO
Hey guys, thanks for the replies. Much appreciated. Trying hard to get to the bottom of this.

To answer the questions, when we first installed it, after about a month it leaked (water) and turns out the copper coil had damage to it. It was replaced under warranty.

I don't notice this (below) when turning on the heater:

Observe for delayed or rough ignition, poor combustion, premature extinction of flame, evidence of boiling, or operation of any diagnostic LED.

I will upload a video of it turning on later today.

It will run fine for about 3 minutes, and then the Service heater light comes on and as far as I can see, there are no LEDs on the circuit board turning on.

I've been texting our pool technician about it and he said when they fixed the leaky heater last time, they replaced the Thermal Regulator. So I don't think that's the problem, but I can check it again. Thanks for that youtube video - I will try it under the sink.

The technician thinks it could be a water flow issue and said to make sure all baskets and filters are clean.

I'll keep trying....
 

JamesW

TFP Expert
Mar 2, 2011
16,072
What pump do you have?
Is there an external bypass?
How much flow is there?
Are you sure that none of the LEDs are lit?
With the problems, there's probably an error in the installation.
 

ColoradoKid

Member
Feb 20, 2019
6
Boulder, CO
Quick update:

We had our technician stop by and he quickly noticed the external temperature gage was installed directly after the outlet pipe from the heater, instead of the proper way of installing the sensor before the heater.

However, don't think this was the main issue. On further inspection, he noticed water in the heater - so the heater could still fire up, but would cycle a few times and then throw the Service light.

So it's going to be a warranty issue with Pentair. And now that it's the 3rd time it's leaked since we installed it in February, I'm hoping they switch out the unit.