MasterTemp 400 Leaking at Pressure Switch and possibly elsewhere.

Pesh

Member
Apr 19, 2020
18
Austin, TX
I noticed my spa wasn't heating properly to find water gushing out the vent of my Mastertemp 400. After removing the front panel, it looks like the water pressure switch has rusted and sprung a leak. See picture below.

Pentair Water Pressure Switch Leaking.jpeg

I'm not sure if there is more damage beyond replacing this component. Not sure if the other pictures attached of the unit are telling of bigger problems.

I noticed the bottom bolts on left and right side of the manifold look pretty rusted and there seems to be a slow drip leak out of both sides. It's not easy to determine if the leak is because of the leak from the water pressure switch or if it is coming from the tub sheet copper coils?

Any guidance would be greatly appreciated. Is this unit worth fixing or replacing? If replace, would 400K BTU heaters do you guys like these days?

Thanks in advance.
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
26,222
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Pentair 42001-0060S Pressure Switch is a $75 part it is worth replacing it and seeing if the heater works.

Your heater looks pretty clean compared to rust buckets we have seen.

Once you get your heater fixed lets discuss how you test and maintain your water chemistry.

I suggest you read ABCs of Pool Water Chemistry
 
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JamesW

TFP Expert
Mar 2, 2011
25,685
Remove one of the bottom manifold bolts to see if water comes out.

If it does, the heat exchanger is leaking and filling up the combustion chamber.

How old is the heater?
 

Pesh

Member
Apr 19, 2020
18
Austin, TX
Pentair 42001-0060S Pressure Switch is a $75 part it is worth replacing it and seeing if the heater works.

Your heater looks pretty clean compared to rust buckets we have seen.

Once you get your heater fixed lets discuss how you test and maintain your water chemistry.

I suggest you read ABCs of Pool Water Chemistry

AJW22 - I use a local pool service to monitor chemicals and handle repair work. Although, I like to do small repairs on my own as a way to learn and save some money. The pool service was able to replace the pressure switch today and the leak completely stopped. Apparently, this switch is fairly universal and they had a Hayward branded solution that looked identical to the Pentair.

The replacement switch seems to have solved the problem. Leak is gone. Heater is working reliably for the few tests I tried throughout the day. Still leak free.
 

Pesh

Member
Apr 19, 2020
18
Austin, TX
Remove one of the bottom manifold bolts to see if water comes out.

If it does, the heat exchanger is leaking and filling up the combustion chamber.

How old is the heater?

JamesW to answer your questions...

See my previous reply to AJW... since the replaced switch seems to have stopped all leaking, I didn't feel the need to mess with the manifold bolts.

The heater was new and installed in 2010.
 
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