Hi. I have a sta rite sa 400na pool heater that just started acting up. the blower and burner come on for a little while but go off. when this happens, the service heater light comes on and burner goes out. after a short period of time the light goes out and the heater fires back up increases temp 1-2 degrees and then light comes on and heater shuts of again. this will happen until it reaches setpoint then seems to work ok? not sure what to look for?
sta rite 400na service heater light
- Thread starter jeffgeer
- Start date
Pool Clown
In The Industry
Did the heater run for about an hour (1 to 2 degree heat rise)?
Or did you mean that it ran for 1 to 2 min and shut off?
If it Runs for 1 to 2 hours:
May be a borderline velocity issue. The variable speed pump could be set too low (if you have a VS pump that is).
Since it is resetting, and fires again on its own, this means it could be:
HLS/AGS Hi limit, and automatic gas shutoff switch. Will shut off the heater when water temp exceeds limits of the switch(s), and then the water cools back down, the switch(s) self-resets, and the heater tries to fire again.
PRS or PS, Pressure switch. Flow/pressure would have to change. IOW go from a workable pressure to a non workable pressure and then back to the original pressure. (using your symptoms) Can't come up with a scenario that would cause that.
AFS (Air flow switch) this switch confirms that he blower is running by checking for a vacuum through the blowers inlet air-horn. An obstruction to the blower inlet would cause this. But like the pressure switch, you would have to have an un-obstructed condition then an obstruction, then un-obstructed again. Not impossible, just unlikely.
SFS Stack flue sensor. Measures exaust temps and opens safety circuit if the exhaust temps rise too high. This switch is not self reset-able, will lockout IGN, and display an error code (E05).
If it is running 1 to 2 min and then shuts off:
Check thermostatic by-pass.
thanks for the reply. I turned it on and didn't check for about 15 mins. when I did, the temp had raised about 10 degrees so I thought all was good, except then it shut off. I went to look at it when it turned back on and all looked normal. I watched go up another degree and then it shut off again and I saw the service heater light come on. about 15-20 seconds later light went off and it fired up again. it did this all the way to setpoint.
Pool Clown
In The Industry
If it doesn't start "cycling" until the water temp gets into the 80's. I would check the thermal bypass.
Hi Pool Clown. I finally got a chance to fire up my pool heater again. It fired up and ran continuously until about 82 degrees, then it would run for appr. a minute and a 1 degree increase then burner would go off and then fire back up in a minute or so. when you said thermal bypass were you speaking of the thermal regulator parts? It seems like I replaced them a few years back, or pulled them out and tested in water somehow? Any help would be much appreciated.
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Sounds like a bad thermal regulator. Remove it and see if it is gunked up.
Yes you can test in water or like I do, I use a pair of pliers to hold it above the heaters exhaust as it runs.
Yes you can test in water or like I do, I use a pair of pliers to hold it above the heaters exhaust as it runs.