Pentair Mastertemp 400

Slpoolowner

Active member
Jul 5, 2018
44
Sugar Land/Texas
Hi everyone!
I have a Petnair Mastertemp 400 that i tried to run here in Houston this weekend, i used it two weeks ago with no issues. WHen i turn the spa on, i hear the blower to my Pentair Mastertemp 400 come on with the correct temperature reading but the heater does not fire or ignite, i simply hear an audible click; the system tries this a two more times then the service heater light turns on. I suspect it is the igniter that has gone bad, does anyone know of a youtube video or tutorial that i can refrence on how to replace this myself? Anythign else i should be looking at or i failed to miss in my diagnosis. Appreciate everyone's assistance.

Thanks
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,451
Northern NJ
Have you opened it up yet? Check that no rodents got inside and chewed on any wires.

Check the gas and wiring around the gas valve and the on/off switch on the gas valve.

Test the ignitor with a multimeter. You should get 70-75 Ohms on the igniter and 120V to the ignitor when it tries to light.

You can find more information at Pentair MasterTemp Heaters - Further Reading
 

Slpoolowner

Active member
Jul 5, 2018
44
Sugar Land/Texas
OK reporting back I opened up the housing and yes a little mouse scurried out and seems to have made a nest at the bottom of the unit. Although I couldn’t see any chewed wires I did notice that a certain wire was knocked out of place. The wire itself seems to be completely corroded so I would need to replace the wire in the connection that it attaches to. I have attached the picture
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,451
Northern NJ
OK reporting back I opened up the housing and yes a little mouse scurried out and seems to have made a nest at the bottom of the unit. Although I couldn’t see any chewed wires I did notice that a certain wire was knocked out of place. The wire itself seems to be completely corroded so I would need to replace the wire in the connection that it attaches to. I have attached the picture
I think that wire runs from the Fenwal to the gas control valve. If the wire is not intact the gas valve will not be energized to open.

If any of the original wiring supplied with this heater must be replaced, installer must supply (No. 18 AWG, 600V, 105° C. U.L. approved AWM low energy stranded) copper wire or it’s equivalent.
 

Slpoolowner

Active member
Jul 5, 2018
44
Sugar Land/Texas
AJ. I actually fixed it! I found an old thread where someone had the same exact issue and you suggested sticking the lead on one of the other slots that is open. I took out the corroded piece out of the connecter and did what you had suggested previously to someone. Fired it up, and i got the ignition to light. I patted myself on the back and poured myself a cold one; i owe you a cold one as well!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,451
Northern NJ
Yup, I remember that. What you posted made it sound like the wire was corroded and not the tab connection. Glad you figured it out.