Sta Rite Heater Troubleshooting - part recommendation please

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C

CanadaDave

0
Jul 28, 2014
33
Windsor
HI all,

Long time lurker, first time poster.

I have a Sta-Rite 400NA pool heater. For he the past month, the heater would work fine for an hour or two, and then flip to 'Service Heater'. I didn't bother taking it apart to check it (I know, dumb), and now it's to the point where I turn it on, it starts up, runs for about 10 seconds, then flips to service heater.

On the bottom of the board, the AGS light is lit red. In looking at the troubleshooting guide, it says to replace either the High Limit switch or the automatic Gas Shutoff switch. (no recent changes to any other pool equipment, so water flow should be fine). I've only owned the heater for a couple of months (moved in recently) so I don't know if either switch has been replaced - does anyone have any advice as to which one to try first (or if I'm totally approaching this wrong in the first place)? Each costs about $45 where I live so it isn't breaking the bank to replace both, but I'd really rather just do the one if I could.

Thanks a ton in advance!
 
I would pull out the thermo regulator and see how that looks. When it gets all gunked up it will cause the unit to do this and light up the high limit switch LED. Iy fools many homeowners when they try to troubleshoot issues.
 
Thanks, PS0303! Does this mean the Thermistor? What's the right way to clean one that's gunked up - or do I replace it?

I'm looking at the diagram and parts list on this page for reference, and it's #9 on the page (just to make sure I'm thinking of the same thing you're referencing): http://www.poolcenter.com/p/sta-rite-max-e-therm-heater-parts-electrical-system

I *really* appreciate the reply and advice - thank you!
 
Just as an additional note - even when it flips to "service heater", it does seem to register the temperature correctly - my pool is somewhere around 77 degrees right now, and it'll read 77 properly (and flip to 78, back to 77, etc). Could it still be the thermistor, do you think?
 
The thermo regulator is not the thermistor. The regulator is inside a compartment down where the inlet and outlet pipes connect. The thermo regulator is basically a car thermostat.

Take a look here and you will see what I'm talking about.

http://www.parts4heating.com/Sta-Rite-77707-0010-Thermal-Regulator-Package-p/77707-0010.htm

Once you pull it out, if it doesn't look visibly gunked up, you can test it by holding a lighter under it and if it doesn't move, it's bad.
 
Hi CanadaDave: I posted a similar situation with my heater. My code is the HLS led light, which calls for replacing the HLS or the AGS. I will visually inspect both switches to see if cleaning does the trick (as it does not seem too complicated). Will keep you posted, but I am planning to do this Friday or weekend.
 
Hi Serge - thanks for the note. I'm going to look into cleaning and testing the thermo regulator tonight as well (thanks again, ps0303!) as long as the weather isn't too bad, and see if that happens to be my issue. I'll report back as well!
 
Well, this is interesting.

I pulled the plastic cap off, and there doesn't appear to be anything in there! Is it possible that the thermal regulator went bad previously, and they just decided to run without it? Will the heater even run like that?

Assuming the answer is "yes", any idea which switch I should try to replace first? :)
 

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It could cause the unit to over heat. Also, a thermal regulator and an internal bypass regulate the water flow through the heat exchanger to maintain the correct outlet temperature.
 
Looks like the AGS was my problem. Heater has been running for about 5 minutes without issue.

The AGS looked like it was a little gunked up inside - I'm guessing that might have been what the culprit was.

My pool place didn't have a thermal regulator in stock, but they could order one. I'll probably do that, just to make sure everything is in good shape.

Thank you, PS0303, for your guidance! :)
 
*ARISE, DEAD THREAD!* :)

So, I was unfortunately mistaken... my problem continues to exist. I went ahead and replaced the high limit switch and put a thermal regulator in as well just to be sure, but I still have a problem.

Additional troubleshooting has revealed a few things:

1) I have a concrete Jacuzzi integrated with my system. I find that when I turn off the returns and drains from the main pool, the heater appears to run properly. Turning off the other items raises my PSI from about 21 to 28-29, but otherwise doesn't change anything. I can run my heater for a few hours no problem at all when it's in that mode, but when I open up all of the other items (lowering the PSI), it stops running after 5-20 minutes.

2) When it stops, it seems to run just fine, then make a small "rattle" before shutting down, flipping the service heater light to on. I hadn't noticed this before, but my wife has. Edit: When it shuts down, it flips to 'service heater' and the blower seems to stay on for a little bit before turning off, so it seems to me like a controlled shutdown, rather than something panicky. That's only my perception, though.

3) I checked with the previous owner, and the Thermistor was replaced about 10 months ago, as was the "blanket" (?). She really never did anything hands-on with the pool and was a little uncomfortable with the questions, but I checked the Thermistor and it does appear to be in pretty new condition, so I think it was replaced.

Any guesses as to what might be accounting for this? I do need to check the underside of the board to make sure the light that is on is still the AGS light, which I'll do tonight if I'm able.
 
CanadaDave said:
*ARISE, DEAD THREAD!* :)

So, I was unfortunately mistaken... my problem continues to exist. I went ahead and replaced the high limit switch and put a thermal regulator in as well just to be sure, but I still have a problem.

Additional troubleshooting has revealed a few things:

1) I have a concrete Jacuzzi integrated with my system. I find that when I turn off the returns and drains from the main pool, the heater appears to run properly. Turning off the other items raises my PSI from about 21 to 28-29, but otherwise doesn't change anything. I can run my heater for a few hours no problem at all when it's in that mode, but when I open up all of the other items (lowering the PSI), it stops running after 5-20 minutes.
Click to expand...

Closing valves and then the heater runs fine almost makes me think that the heater is only plumbed for the spa. Also are you sure there isn't a valve that allows the heater to be bypassed when in regular pool mode?

2) When it stops, it seems to run just fine, then make a small "rattle" before shutting down, flipping the service heater light to on. I hadn't noticed this before, but my wife has. Edit: When it shuts down, it flips to 'service heater' and the blower seems to stay on for a little bit before turning off, so it seems to me like a controlled shutdown, rather than something panicky. That's only my perception, though.
Click to expand...

Yes the blower will run for a short time to help cool things down.

3) I checked with the previous owner, and the Thermistor was replaced about 10 months ago, as was the "blanket" (?). She really never did anything hands-on with the pool and was a little uncomfortable with the questions, but I checked the Thermistor and it does appear to be in pretty new condition, so I think it was replaced.

Any guesses as to what might be accounting for this? I do need to check the underside of the board to make sure the light that is on is still the AGS light, which I'll do tonight if I'm able.
Click to expand...

Not sure what "blanket" means. Check the light on the card under the dome when the service light comes on. Can you post some pictures of your setup and valves as maybe this could shed some light on to the issue.
 
Have you checked that manifold by-pass is still intact and has not broken?
Page 52 number 8.
http://www.pentairpool.com/pdfs/MaxEThermEngOM.pdf


Your initial complaint reminds me of only one other time i had a ICM go bad (page 53 number 12) in this particular way. The heater would run for about 45 min then shut down. Are you able to reset the heater (power off then back on) and then be able to have it run for another hour before turning off again?
 
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