My htr is about 10 years old and has worked great until now. When I turn it on it cycles as it should (blower comes on, after about 15 sec the gas fires and good heat comes out of the flue and water). It then runs fine for about 5-10 minutes and then abruptly shuts off the blower and the Service and AFS LED's come on. I have replaced the AFS and tubing and also the flue switch but it didn't help. If I recycle the power to the unit and wait about 5 minutes the unit will come back on and does the same thing. The motor sounds strong but I am not sure what it should sound like. It sounds like something is heating up and shutting the unit down and it will restart after cooling down?? AFS and Service LED's are the only lights that come on. Would really appreciate some ideas!!
Sta-Rite SR400NA heater AFS problem
- Thread starter Ntouchton
- Start date
Pool Clown
In The Industry
You got the air flow switch error because the blower shut off. Not being there to diagnose the heater in person, i would guess either the FENWAL, which does the switching for the ignitor and blower, or it could be the main board, that gives instruction to the FENWAL.
This sounds like an electronic malfunction (blower stops abruptly) as opposed to something that is happening to cause a safety circuit shutdown. If you had a component of the safety circuit either performing properly, or failing, the heater would still shut down properly (gas shut off, then blower remains on to cool down, then shut down).
Note: If you had a problem with the thermostatic by-pass, the heater would cycle, or try to restart again. Does your heater do this? Or is it shutting off, and staying off?
This sounds like an electronic malfunction (blower stops abruptly) as opposed to something that is happening to cause a safety circuit shutdown. If you had a component of the safety circuit either performing properly, or failing, the heater would still shut down properly (gas shut off, then blower remains on to cool down, then shut down).
Note: If you had a problem with the thermostatic by-pass, the heater would cycle, or try to restart again. Does your heater do this? Or is it shutting off, and staying off?
10 year old unit so it could very well be the blower not strong enough. Of course only someone that works on them all the time would be able to tell if the blower is strong or not.
The failure mode is very consistent in sequence and time. When I first turn it on the blower comes on but no heat. Approximately 20 sec later the heater turns on and I get good heat. Everything remain constant for 4-5 minutes when suddenly I hear a click (gas valve I think) and at the same time the blower turns off and winds down and the lights come on. It does not try to restart and I have to turn all power off to get it to start again and when it does start it follows the exact same sequence as above. The fact that it runs fine for the 1st 4-5 minutes makes me think that it is heat related
Pool Clown
In The Industry
I would still say electronic ONLY if you hear the click (gas valve) first, THEN blower shuts off. If blower shuts off first, then i would say blower motor thermal cut off because motor overheated. If that were the case, you probably wouldn't be able to cyclepower and get the blower to start again right away. Thermal cutoff lasts until the motor cools down and switch resets (if that motor even has one). Can be anywhere from 15-30 min.
And again, any heat (water or fire) related problem would have a proper shut down (post purge).
And again, any heat (water or fire) related problem would have a proper shut down (post purge).
Pool Clown
In The Industry
Click you hear is the solenoid in the gas valve loosing current and closing. That voltage also comes from the Fenwall via instruction from the board. So is the FENWALL failing to hold relays? Or is it just doing what it is told from the board? You see the dilemma here? I dont want to, or can't tell you with certainty that it is one or the other, so i must tell you it MAY be one, the other, or both...
That is the best I can do without being there.
That is the best I can do without being there.