Mastertemp Issue

Pool8686

In The Industry
Jan 1, 2021
2
Arizona
I’m new to this forum. I’m currently repairing a mastertemp 400 at a commercial property and have a very strange issue. We recently replaced the gas valve on this heater and now two weeks later it is not working. Currently I’m not getting power to gas valve itself. The ignition control module is functioning and outputting 24v on the valve wire to the control board. We assumed this was potentially a faulty board and I installed test board but still have the same issue.
 

Pool8686

In The Industry
Jan 1, 2021
2
Arizona
Also I know everyone is going to tell me to find out where I’m loosing voltage but that’s the problem I’m not loosing voltage anywhere except I don’t have 24v at the valve or on the output to the valve. Also to clarify we have tried a new control board and also a second new one just incase the replacement was bad.
 

swamprat69

Well-known member
Mar 30, 2019
372
Las Vegas, NV
How are you checking for 24 volts? If you do not show 24 volts at the gas valve, I would remove the AGS,SFS,GAS, 6 pin connector from the circuit board and check for 24 volts on the circuit board side of the connector at the 2 GAS connections. If you have 24 volts at the circuit board GAS side of the connector, I would suspect that have a connection pin that has been pushed partially out of the connection housing. The other possibility would be an open wire between the connector ( either side ) and the gas valve which you could confirm by checking continuity.