Max-E-Therm Automation Wiring Shorted

birdman579

Member
Dec 18, 2020
19
Maryland
Pool Size
30000
Surface
Plaster
Chlorine
Liquid Chlorine
I have a Sta Rite Max-E-Therm gas heater for my pool that is wired to my Intellitouch system. Last weekend, the automation system stopped turning the heater off. Even with the pool pump off, the heater would stay on until the pressure sensor on the heater shut it off. I did some investigating tonight and the 2-wire connection between the fireman's switch and intellitouch is shorted. I mean the actual wires are shorted! Each end is fine (automation side & heater side) so it appears the wire itself failed and shorted together. I pulled up the heater manual and it calls for 105C rated wire for the 24V control lines. Where do I find this type of wire and what kind is it? My guess is the original installer (not me) used cheap thermostat wire that is only rated for 60C. Over time, the insulation melted and shorted together. I have a separate spa heater and the cable has 8 wires total with 4 going to the spa and 4 going to the pool heater. My guess is the wires shorted at the spa heater because they are daisy chained. Overall, it seems like the installer did not follow the manufacturer's requirements. So... where can I get 105C solid core wire for the 2-wire connection??? This should be an easy fix once I can find some wire.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
38,892
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
A quick search found this. Probably others out there…



Product Description​


#20 solid copper wire with modern insulation and lacquered cotton braid finish. Various length spools. Multiple colors available. 105°C temperature rating, 600V.
Solid Core: Spools (25, 50, 1000 feet)

Stranded Core: 10 feet
Spools (25, 50, 1000 feet)
 

birdman579

Member
Dec 18, 2020
19
Maryland
Pool Size
30000
Surface
Plaster
Chlorine
Liquid Chlorine
UPDATE: I found marine wire in-stock at Amazon that met the temperature and insulation requirements from Sta Rite. It turns out the control wires were shorted together because a mouse made a nest in the spa heater control box. The mouse chewed the 2 wires that went to the pool heater and they shorted causing my issue. Ugh. I hate mice! Everything is fixed and working well.

The other issue I discovered during the repair is the junction box where power comes into the heater was completely filled with water! My hot and neutral wires have been sitting in water for months if not more! The bonding wire was also disconnected! The junction box has a poor fitting cover with no gaskets or seals. There is a cutout in the bezel for the gas line so it rains right on the top of the junction box. I dried everything thoroughly and taped the top shut with electrical tape. I also drilled a drain hole in the bottom as a backup. The water was so bad the entire conduit was full of water! That is also drained now. I guess I should upgrade to a GFCI breaker on my heater circuit.
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
4,185
FL

birdman579

You need to put mesh wire over the vents on this unit to keep the mice out.

There is a company that sells pre-cut mesh panels exactly fort his heater. I am not associated with the company, Products | MK Rat Proofing, that makes them but I have used them on several of my customers units to prevent the mice from getting in.

And your water issue is most likely due to water getting into the conduit that's feeding the heater. I see it from time to time when I disconnect the power on units. I drain water out of the conduit. It happens on many different brands of heaters.
 
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