On startup of old mastertemp 400, panel initializes with 888, 128, r13 and then goes dark. No blower no heat.
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Posted

I have a mastertemp 400 lp, 460737. Installed in 2007. When powered-on, the unit's electronic display activates with startup codes 888, 128, and r13. All the panel leds (spa, pool, service sys, service heat) activate momentarily and then all goes dark. There is no blower action or any call for heat. I have replaced the old control board (r8) and the thermistor (as it was showing the water temp to be 100 even though there was no heat). None of the diagnostic leds (ags, afs, etc) are lit-up. I have followed the troubleshooting steps with no success. I have ordered a new transformer on the hope that this may solve it. Since there is power getting to the control board and membrane pad, its unlikely that the transformer is the issue. I have a full tank of propane and gas flows well to heater.
Any further troubleshooting guidance would be appreciated.

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Richard's picture
Tech, Pentair
Without the blower coming on,
Richard's picture
Tech, Pentair
Posted

Without the blower coming on, there could be an issue with the blower itself, or could be a safety circuit leaving the board. I would recommend to give us a call to go through the troubleshooting steps when you are at the heater and ready to run some tests with a multimeter at 1-800-831-7133

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Thanks Richard, as the
Posted

Thanks Richard, as the membrane pad is completely dark I suspect that a safety circuit kicking in and stopping all functions (blower, gas flow, etc). Just need to figure out which safety switch that is. None of the diagnostic leds (ags, afs, etc) are lit-up, so it must be something else. I will call the number on Friday. By the way, After I had replaced the thermistor, but before I replaced the board (they arrived in the mail on different days), I was able to get the unit to turn-on once, run the blower, and call for heat, but it stopped and showed a "service heat" led. After that one occurrence, it didn't start up again (just had the dark membrane symptom). Jon

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Update on troubleshooting. I
Posted

Update on troubleshooting. I replaced the transformer friday night. No luck. I was not able to call Pentair on Friday due to work issues so I did some additional troubleshooting. I checked to ensure there is power flowing to all start-up sensors (Therm, PS, HLS, AFS). Power is flowing to each sensor and jumpering them did not help get the unit going. I then jumpered the f1 and f2 blower wires and turned the unit on. Blower came on, so its functional. 24vac power is getting from control board to the IND terminal on the ignition control module (ICM), which should tell the ICM to close the curcuit to the f1 / f2 terminals (to run the blower). I also checked the TH wire from the control board to ignition module, TH wire is pushing 24vac with the blower running (f1/f2 jumpered), as it should. I think my ICM is dead. The new control board I replaced earlier this work came with paperwork that clearly described how the start-up/fire-up cycle works, how power flows from one sensor to the next and it has been very useful in this troubleshooting.

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Jon or Richard (Pentair Tech)
Posted

Jon or Richard (Pentair Tech) - I have the exact same issue. Did ICM replacement solve this for you? I see that was your next step but there's no follow up confirming it worked.

I've replaced PC board. Panel initializes with 888, 128, r13 and then goes dark. No blower no heat. Troubleshooted with Pentair via phone. Ran a bunch of diagnostics they said is was temp sensor. Replaced temp sensor. Nope. Same issue. Called Pentair again. Isolated remote control system. No difference. Tech said it must be the (new) PC board. Put in the old PC board - nothing. Blank screen. Ordered another new PC board ... getting expensive...

Hope to hear back to see if ICM replacement worked.

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Hi Roger. Yes. Problem
Posted

Hi Roger. Yes. Problem solved after replacing the ICM as well as a high temp cutoff sensor (if I recall correctly). Its been awhile .....

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Thanks Jon. Really appreciate
Posted

Thanks Jon. Really appreciate the response! I'll try ICM replacement and post back on the results.

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Thanks Jon. Really appreciate
Posted

Thanks Jon. Really appreciate the response! I'll try ICM replacement and post back on the results.

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Update: ICM and Temp Cutoff
Posted

Update: ICM and Temp Cutoff sensor did not work for me. Neither did transformer. Looking into a short in the 24v power lines going from the transformer to the pc board... argh

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I had the same problem. Found
Posted

I had the same problem. Found this in only one place on the web and it worked for me. After the 888,128, r13 was displayed I pushed the "spa on" button and adjusted the temperature to 103 and the heater fired and is now working... Hope this solves your issues.

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Warren! This was spot on!!
Posted

Warren! This was spot on!! Fired right up. Not sure if was due to it sitting all winter, but this was the ticket to get it running. Thanks guy!

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Sorry to hear that Roger. I
Posted

Sorry to hear that Roger. I presume none of the diagnostic leds on the circuit board are lit ? I think I had a bad circuit board and a bad temp cutoff switch. Once I replaced the circuit board, the led lit up telling me I had a bad high temp cutoff. It was frustrating. I ended up replacing quite a few things before hitting the right combination (membrane pad, circuit board, transformer, thermistor, high temp cutoff, and ICM.

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