Mastertemp 400 error R13

wireform

Silver Supporter
In The Industry
Aug 15, 2017
3,312
Spring Valley, NY
I want to arm myself before I visit the customer. Customers states heater throwing R13 code and no other numbers. I asked if blower motor comes on, said no. He says just R13 comes on and then screen is blank with no blower working. Is there a fuse that can cause this? Any help with diagnostics will be greatly appreciated. Thanks, Allan
 

Poolbreh

In The Industry
Jul 31, 2021
300
San Diego
You need to make sure heat settings are correct on automation so there is demand, it will turn on or off heater through fireman. Make sure spa is enabled on heater is set to max. The automation will turn the heater off and on through fireman.
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
3,312
Spring Valley, NY
What’s it’s hooked up to? An intermatic timer?
Yes a timer which is also for the filter pump. Got there with not much time left to the day so wasn't able to diagnose yet but the fireman's switch isn't there and instead there's a glass tube fuse in it's place which isn't blown. As I understand these heaters don't have a fireman's switch due to the closed design of the heating chamber. I did verify power into the heater and the transformer is putting out 24 volt. Not sure how to check the Fenwal. I did find an empty nest as per picture but non of the wiring has been touched.
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
3,312
Spring Valley, NY
It has a fireman's switch.

Is the switch connected to the timer?

Do you have a picture of the fireman's switch and the timer?
Got what you're saying. That's the switch that trips off a few minutes before the time kicks it to off to cool down the heater before pump turns off. So you're saying that switch is bad so then why would I get the momentarily r13 on the display when the switch is bad, shouldn't it not have power at all.
 

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JamesW

TFP Expert
Mar 2, 2011
28,291
The heater will go through the boot up process and show the initial 888 128 R13 and then it will operate according to the fireman's switch.

The heater still has power.

The fireman's switch doesn't remove power from the heater, it just tells it to turn on or off.

Try jumping out the fireman's switch to see if the heater will operate normally.

The heater comes with a small yellow jumper wire on the fireman's switch that gets removed when you want to use a remote control.

The small yellow jumper wire might still be in the box.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,698
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
MasterTemp powers up with the boot up R13 when the fireman’s switch is closed. Then screen goes blank if no call for heat and it sits idle.

If the heater does not respond to the keypad then the keypad may be defective. They go bad.

Disconnect the wire to the timer and tie the two yellow wires together so the heater is on local control. That gets the fireman’s switch out of the circuit. If the heater does not respond to the keypad then it is probably defective.
 

JamesW

TFP Expert
Mar 2, 2011
28,291
The boot up only happens when you first apply power to the heater.

Once the heater is powered, the fireman's switch just acts like pushing the on button on the control panel.

The yellow wire below was cut to use a remote control switch and then reconnected to use the heater control.

1628258356053.png
 

JamesW

TFP Expert
Mar 2, 2011
28,291
The yellow wire jumper is in place.

When you apply power, the boot up of 888 128 R13 should display and then you should be able to press the "Pool On" or "Spa On" button to start the heater.

Check the temperature of the water on the display and the set temperature to see if the set temperature is above the water temperature.
 

JamesW

TFP Expert
Mar 2, 2011
28,291
It looks like mice have been in the heater and they have been chewing on wires and peeing everywhere.

This creates a lot of issues.

Below shows how to see if the membrane pad is bad.

 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
3,312
Spring Valley, NY
It looks like mice have been in the heater and they have been chewing on wires and peeing everywhere.

This creates a lot of issues.

Below shows how to see if the membrane pad is bad.

There was a nest in there but unsure from when as I've never opened this one. The only wire chewed a bit is the yellow jumper but all the strands are there, only chewed through the insulation and only that wire. Will be covering the open slot on the top of the box with wire mesh and 2 self tapping screws.
 
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