Ok, I forged on with this perplexing puzzle.
As mentioned, when Spa ON, the led display was reading way high water temps, 102, 107, 105, etc. Current actual water temp is around 81.
I traced info to a misreading thermister as most likely culprit.
Old one on the left, looks like corrosion.
After thermister replacement, and Spa ON, the water temperature reading was correct.
However, I now saw that Service Heater was on, the back of the board showed AFS error.
I had decided to get an inexpensive aftermarket PCB along with the thermister - my thinking was that I wasn't going to buy a $500 PCB just to see if it made a difference. I installed the replacement PCB only as a verification and it also showed the same water temp, Service Heater light and AFS led on the back.
This was telling me that maybe the water temp reading (thermister) was an additional problem that was unknown at the beginning.
With the water temp reading resolved, I took a look at the AFS issue.
I know that the AFS itself is functional from earlier testing. What it's telling me in this case is the obvious - the air blower isn't coming on, therefore no airflow, therefore the AFS isn't closing.
So now the troubleshooting is somewhat more focused on what the blower motor needs to turn on.
I went back through the wiring diagram, looking at the motor circuit, which is set up for 240v.
I always verify that the actual wiring color/tag matches the wiring diagram.
I don't see a start capacitor in the diagram, so I'm thinking that this system doesn't have one.
That would be a simple check for a no-start.
I also am checking wiring continuity through the various connectors.
Something curious when I checked the Fenwal F1 and F2 terminals ...
- F1 is constant 120v as expected.
- I was wrong yesterday about the F2 terminal - with Spa OFF, if I unplug the motor harness plug, I get 0v at the F2, but with the motor plugged in (still Spa OFF), F2 sees a constant 120v. This to me seems wrong as F1-F2 should be a relay activated by Spa ON command.
- There is no audible click of any sort at the Fenwal (F1/F2 relay) when Spa ON.
- The red diag led on the Fenwal is never lit or flashing.
- I also want to re-verify why no 24v at the IND terminal at the Fenwal, with either the old or the new PCB.
Next steps:
- I'll finish going through the unit wiring to be sure connectors are ok, etc. There's no visibly damaged wiring anywhere.
- I believe that if I (turn off power first) connect the F1/F2 wiring directly, the blower motor should run.
- I see some additional means of testing the motor operation via alternate wire connections, but right now I'm not completely familiar with that.
- If the blower motor runs then indeed the Fenwal may be at fault.
Right now I'm trying to understand the 6 wires going to the motor, which appears to be wired for 240v. I could see 2 hot and a neutral but I really don't yet get the other 3 wires. I'm trying to find a motor schematic to understand better,
especially before trying to test operation.
Edit, I found this that I think can help guide me....
www.troublefreepool.com
As mentioned, when Spa ON, the led display was reading way high water temps, 102, 107, 105, etc. Current actual water temp is around 81.
I traced info to a misreading thermister as most likely culprit.
Old one on the left, looks like corrosion.
After thermister replacement, and Spa ON, the water temperature reading was correct.
However, I now saw that Service Heater was on, the back of the board showed AFS error.
I had decided to get an inexpensive aftermarket PCB along with the thermister - my thinking was that I wasn't going to buy a $500 PCB just to see if it made a difference. I installed the replacement PCB only as a verification and it also showed the same water temp, Service Heater light and AFS led on the back.
This was telling me that maybe the water temp reading (thermister) was an additional problem that was unknown at the beginning.
With the water temp reading resolved, I took a look at the AFS issue.
I know that the AFS itself is functional from earlier testing. What it's telling me in this case is the obvious - the air blower isn't coming on, therefore no airflow, therefore the AFS isn't closing.
So now the troubleshooting is somewhat more focused on what the blower motor needs to turn on.
I went back through the wiring diagram, looking at the motor circuit, which is set up for 240v.
I always verify that the actual wiring color/tag matches the wiring diagram.
I don't see a start capacitor in the diagram, so I'm thinking that this system doesn't have one.
That would be a simple check for a no-start.
I also am checking wiring continuity through the various connectors.
Something curious when I checked the Fenwal F1 and F2 terminals ...
- F1 is constant 120v as expected.
- I was wrong yesterday about the F2 terminal - with Spa OFF, if I unplug the motor harness plug, I get 0v at the F2, but with the motor plugged in (still Spa OFF), F2 sees a constant 120v. This to me seems wrong as F1-F2 should be a relay activated by Spa ON command.
- There is no audible click of any sort at the Fenwal (F1/F2 relay) when Spa ON.
- The red diag led on the Fenwal is never lit or flashing.
- I also want to re-verify why no 24v at the IND terminal at the Fenwal, with either the old or the new PCB.
Next steps:
- I'll finish going through the unit wiring to be sure connectors are ok, etc. There's no visibly damaged wiring anywhere.
- I believe that if I (turn off power first) connect the F1/F2 wiring directly, the blower motor should run.
- I see some additional means of testing the motor operation via alternate wire connections, but right now I'm not completely familiar with that.
- If the blower motor runs then indeed the Fenwal may be at fault.
Right now I'm trying to understand the 6 wires going to the motor, which appears to be wired for 240v. I could see 2 hot and a neutral but I really don't yet get the other 3 wires. I'm trying to find a motor schematic to understand better,
especially before trying to test operation.
Edit, I found this that I think can help guide me....
Unexplained voltage Reading from Mastertemp 400 Blower Motor
I suspect I have a bad motor, but wanted to check here before replacing it. I'm getting a voltage reading Pentair tech support could not explain when I talked to them by phone. My heater will not start. After the failed starts the following are on: Service Heater, AFS LED, and the ICM LED...
www.troublefreepool.com
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