Pentair MasterTemp 400 - no lights on the panel and not coming on

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D

dbellando

Silver Supporter
Dec 30, 2022
6
Dallas Texas
My Pentair Mastertemp 400 is 7 yrs old. No display and the heater is not coming on when I use the Screen Logix software nor when I use the EasyTouch control panel.
I have checked the input to the transformer (240v coming in and 24 volts are coming out), so that seems to be OK.
I have checked the main fuse (24v on both sides and pulled it out and checked for continuity and it was good) so that seems to be OK.
I followed a Youtube video and disconnected the membrane display from the control panel and shorted pins 1 and 2 (closest to the yellow button) and it did NOT turn on (so I'm thinking the membrane display is OK).
Does not appear to be any rust or corrosion on the control board itself.

Any thoughts on next steps for testing?
Thanks in advance
I'm in dallas texas BTW.
 
With the power off, at the area where the EZ Touch is connected (below the fuse) remove the wiring from the automation and twist the two ends of the yellow wire together. Power on, start the pump, and be sure the heater is turned on at the touch pad.
If the heater lights, check that 2-conductor wire all the way to the panel for any break in the line (most likely caused by rodent damage). After that, if you don't see damage, you can reconnect the wire in the heater, disconnect the wire in the panel, twist the ends together, and see if the heater lights. If it does, the problem is in the EZ touch, perhaps a bad water-temp sensor. If that sensor is bad it won't allow the automation to light the heater.
 
Thanks for your willingness to answer, but I'm not sure what you mean by "wiring from the automation". I think I need to understand this otherwise I could do some damage. I took off the cover for the EZ touch. Which wires do you mean? thanks.PanelRemoved.jpg
 
dbellando said:
Thanks for your willingness to answer, but I'm not sure what you mean by "wiring from the automation". I think I need to understand this otherwise I could do some damage. I took off the cover for the EZ touch. Which wires do you mean? thanks.
Click to expand...

He means in the heater. The "firemans switch" wires.

450px-Pentair_MasterTemp_Firemans_Switch.jpg


Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com www.troublefreepool.com
 
The 2 wires from the Firemans Switch connect to J19 on the low voltage top panel of the EasyTouch system...

1672432099915.png
 
dbellando said:
Thanks for your willingness to answer, but I'm not sure what you mean by "wiring from the automation". I think I need to understand this otherwise I could do some damage. I took off the cover for the EZ touch. Which wires do you mean? thanks.View attachment 466978
Click to expand...
There should be a small 2-conductor wire coming from the heater and attaching at the circuit board above the relay/high voltage compartment. It could be that white wire in the compartment at the left of your picture.
 
I connected the two wires (with some duct tape - see picture) and still no display. Just to be sure that I didn't have two issues, while the wires were connected (thus by passing the Fireman Switch) I connected pins 1 and 2 on the controller board, with the membrane panel connect taken off, so be sure that wasn't the issue. The heater still did not come on. No display.

Again, thanks for your thoughts. Any other ideas?FiremansSwirchWiresEngaged.jpg
 
Do you have a multimeter?

Check for 24V AC on the pins of the J7 plug. Check for continuity on the right two pins of the J7 plug.

full
 

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You did not jumper the firemans switch contacts on the heater.

The red arrows point to the contacts you need to connect a wire between.

That is why you don't have 24V and the heater powering up.

The wires you connected together with tape run to the EasyTouch.

FiremansSwirchWiresEngaged.jpg
 
OK. It is fixed! Thanks to all who offered their advice and wisdom.
Just in case anyone else might find this thread useful, let me give you my journey.
I checked the input to the transformer (240v coming in and 24 volts are coming out), so that was good.
I checked the main fuse (24v on both sides and pulled it out and checked for continuity and it was good) so that was good.
I followed a Youtube video and disconnected the membrane display from the control panel and shorted pins 1 and 2 (closest to the yellow button) and it did NOT turn on, so the membrane display panel was good.
I bypassed the Fireman switch (ajw22, you were correct. I did not do it correctly do I retested per your diagram). It still did not turn on.
I tested the J7 plug and it had continuity in the two right pins and had 24v AC on the other two pins (note: Be sure to turn the power on when you test this.. I didn't do that at first and of course, I did not see the 24V).

So what was the problem?
When I plugged the J7 connector back in, it started working.
My guess was a dirty connector pin.
I bought some contact cleaner (safe for PCBs) and cleaned all the contacts on the controller board.

It works well now. If you are having this issue, of the heater not working, I encourage you to try this first.

Thanks again for all your help. I learned a ton and now that I am member, hope to pay some of that back.

Happy New Year!
 
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