Mastertemp 400 - Won't ignite

Justantru

Member
Apr 16, 2021
18
Kaysville, Utah
Pool Size
10000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Hello,

My mastertemp 400 heater does not recycle and service heater light turns on immediately. The "High Limit Switch" error code is highlighted on the control board. Does this just mean I need to replace the high limit switch?
 
Last edited:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,054
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Test the HLS continuity using a multimeter. If the HLS is open when the heater is cold then the switch fails and needs replacement.

Does it throw the HLS fault before the heater starts up?
 

Justantru

Member
Apr 16, 2021
18
Kaysville, Utah
Pool Size
10000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Test the HLS continuity using a multimeter. If the HLS is open when the heater is cold then the switch fails and needs replacement.

Does it throw the HLS fault before the heater starts up?
Yes. I order a new switch and will have it installed tomorrow. If that does not work, what is my next step?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,054
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
See what error you get after you replace the HLS.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,054
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60

Justantru

Member
Apr 16, 2021
18
Kaysville, Utah
Pool Size
10000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Sorry to bother you, but I am still having problems. The heater is now working for a while, but cycles to service for 10 min or so then turns back on. It takes forever to heat the SPA. Thoughts on my next step?
 
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