New Mastertemp problem

[davidgelb]

Hi all, I just had a brand new Pent air Mastertemp 300 installed and immediately noticed a problem. When it first turns on, it flashes heating as it calls for heat and then fires up normally. The problem begins almost exactly 2 minutes later...heat cuts off and the "service heater" light comes on solid for 30 seconds. Then it shuts off, and the "heating" light flashes for 20 seconds as it calls for heat. It then repeats this over and over again with the same durations. Any ideas as to what might be causing this?

Thank you,
David

 

[JamesW]

Contact the installer to have them fix the problem. Leave the heater off until fixed.

 

[davidgelb]

I checked and it is the High Limit switch that is tripping. Why would this happen on a new heater?

 

[davidgelb]

Also, I am getting an intermittent high pitch whine (flame too rich). Suggestions?

 

[davidgelb]

OK, I figured something out. I tried leaning out the mixture by partially closing the supply valve...just enough until the whine went away. Since doing that, the heater is not shutting off any more and is continually heating properly. The Gas company upgraded our meter AFTER the heater was installed, which is why the installer tested it and it worked perfectly...less fuel when it was installed. With the larger meter, I assume it was just receiving too much fuel.

Would adjusting down the internal gas valve be the correct course of action? I don't want to leave the supply valve partially closed because if it ever gets bumped, it will start having issues again.

Thank you!

-David

 

[Zadd]

A plumber can install a new adjustable flow regulator on your pipe. This should allow them set it to feed the heater the correct columns of water as required by your heater and listed in the manual. I think we paid $140 for the regulator plus the service charge.

 

[davidgelb]

Hmmmm...it started doing it again...so not sure if it is still a mixture issue or if it is something else. Any other things to try?

 

[ps0303]

The problem you are experiencing has to do with air being sucked into the unit. To confirm, turn unit on with the covers off and when it makes this sound partially cover the white air orifice and the sound should go away. If what I said works, then I would call Pentair support and see what they tell you. I have heard they make a different orifice to combat this issue. However I have never had to use one.

If the gas company installed their stuff after the unit was installed, I would hope they would have made any adjustments to their side.

 

[JamesW]

If you paid someone to install this heater, then they should fix it. You are risking ruining the heater and possibly causing a fire or explosion.

 

[davidgelb]

OK, my installed checked everything out - I haven't had the heater cycling issue since, but I am still getting the high pitch whine. I had the gas pressure checked at the heater and it is within spec (about 9-10" W.C. when off, about 6-7" W.C. when running). I am currently on hold waiting for Pentair to pick up, but any other ideas as to why I am getting the whine?