heater blower fan on all the time (uncommanded)

Jontmiller

Active member
Mar 28, 2013
26
Newtown, CT
Symptoms....heater blower on whenever filter pump turned on regardless of pool heat on or off.

Pentair Master Temp 400. Came out to clean pool and breaker was tripped, (happens on occasion....once or twice a season) reset breaker and the filter pump came on but the heater blower came on as well. (just the blower...no ignition) <<scratches head>>

Turned on heater...heard attempted ignition but no light off...no error codes. Turned on and off a few more times, opened panel and wiggled some wires. Finally unplugged the blower motor and the filter / swg operating normally (Jandy controller)

Heater is about 7 years old, got attacked by mice a few years ago and I successfully repaired all chewed up wires. Does not get used very often, early and late in the season but during summer pool gets warm enough on its own. We just went through the extended power outage here in CT and while the circuit breaker was off for much of the outage, it was still on while the power was failing and I used the generator to run the filter for a few hours on day two.

It might be my imagination but I swear I could smell a slight acrid electric small under the panel....I am wondering if the main panel got zapped or something with either a power surge during the storm or dirty electricity from the generator. (portable unit)

Any suggestions where to start would be appreciated. I hate to just start throwing parts at it.

pics for clicks

Untitled by Jon Miller, on Flickr
 

swamprat69

Well-known member
Mar 30, 2019
328
Las Vegas, NV
The heater blower should only come on when the heater is being asked to heat ( when you have 24Vac between TH and GND on the ignition control ). If you do not have 24Vac betweeen between TH and GND on the ignition control and the blower is running, I would suspect that the blower relay contacts in the ignition control are welded shut for some reason. I would check the blower run capacitor microfarads to see if the blower has been drawing excessive amperage due to capacitor failure/weakness. If the capacitor is ok, I would shut off all power and give the ignition control a couple of sharp raps with the handle end of a screwdriver. If that stops the blower from running ( or even if it doesn't ), i would replace the ignition control because the power to the blower is supplied by the relay in the ignition control. The main panel ( operating control ) when asking for heat should supply 24 Vac between GND and the safeties starting with the water pressure switch and ending with 24Vac between GND and TH on the ignition control which will start the ignition sequence. It is possible that you have more than one problem caused by an electrical fault, so I would take one thing at a time. If the blower relay contacts were welded shut, when you had the heater call for heat from the operating control you should have seen 24Vac between GND and TH on the ignition control and if all the safeties were operating normally it should have fired up. Check wiring diagram and schematic on pages 31 and 32 of the manual. https://www.pentairpoolme.com/uploads/document/file/554/Manual_MasterTemp.pdf
 

Jontmiller

Active member
Mar 28, 2013
26
Newtown, CT
The heater blower should only come on when the heater is being asked to heat ( when you have 24Vac between TH and GND on the ignition control ). If you do not have 24Vac betweeen between TH and GND on the ignition control and the blower is running, I would suspect that the blower relay contacts in the ignition control are welded shut for some reason. I would check the blower run capacitor microfarads to see if the blower has been drawing excessive amperage due to capacitor failure/weakness. If the capacitor is ok, I would shut off all power and give the ignition control a couple of sharp raps with the handle end of a screwdriver. If that stops the blower from running ( or even if it doesn't ), i would replace the ignition control because the power to the blower is supplied by the relay in the ignition control. The main panel ( operating control ) when asking for heat should supply 24 Vac between GND and the safeties starting with the water pressure switch and ending with 24Vac between GND and TH on the ignition control which will start the ignition sequence. It is possible that you have more than one problem caused by an electrical fault, so I would take one thing at a time. If the blower relay contacts were welded shut, when you had the heater call for heat from the operating control you should have seen 24Vac between GND and TH on the ignition control and if all the safeties were operating normally it should have fired up. Check wiring diagram and schematic on pages 31 and 32 of the manual. https://www.pentairpoolme.com/uploads/document/file/554/Manual_MasterTemp.pdf
Thanks this gives me a great place to start....appreciate the detailed response
 

Jontmiller

Active member
Mar 28, 2013
26
Newtown, CT
Thanks again for the quick replies....embarrassed to say after looking a bit more I was able to make a small flame come out of the ignition control module....so something obviously shorting in there.


While waiting for parts any reason I can't keep blower unplugged and run just the filter. Guess along those lines I can just disable the heater control altogether. Thoughts as to cause of this in the first place? (things to look for so it doesn't happen again) or is the ignition control a common failure point at this age.
 

Jontmiller

Active member
Mar 28, 2013
26
Newtown, CT
Follow up for anyone searching down the road. Replaced the ignition unit and all ops normal now. Thank you to the quick replies getting me moving the right direction on the diagnosis. Still unsure of the cause, there has not been any rodents in the heater for years, but it was a pretty good infestation when first discovered...suspect some urine got in there and eventually lead to the short...or maybe they just go bad.

Untitled by Jon Miller, on Flickr

Untitled by Jon Miller, on Flickr
 
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