08 PT Zone 1 Furnace Blows Cold Air

[Michael Lasseter]

My heat exchangers for our Zone 1 furnace blow cold air.  The other zones heat nicely.  I verified that the appropriate pump light is on and that there are no fault lights.   I tried to find a related thread on the forum search engine to no avail.   i'm sure one is there but my lack of experience using the search engine is giving me fits. I haven't a clue what to try next.

[David T. Richelderfer]

http://beaveramb.org/forum/index.php/topic,31.msg119.html#msg119

[Gerald Farris]

Michael,
There are two very likely causes for your problem. The first one is a stuck check valve, and if that is it, a couple of raps with a screw driver handle on the valve will cure it. The other one is a bad pump drive. Aqua Hot was using pumps with a magnetic drive for the impeller about the time your coach was made. These magnetic drives fail and either do not turn the impeller or turn it so slow that the zone will not heat. The only cure for a drive failure is a new pump. The Aqua Hot control board can not set a trouble code for either problem since the electric motor is running as normal and the control board can not measure flow rates. You can access the Aqua Hot repair manual for your specific model unit on the Aqua Hot website to determine the location of your check valve and zone pumps.

Gerald   

[Michael Lasseter]

Gerald,

Thank you for the information.  It was very timely.  Within the last 30 minutes I managed to eyeball the pumps.  One, the most difficult to reach, makes about a 1/16 of a revolution at a time.  Rats, I was hoping for a stuck check valve.  I'll order a new pump Monday.

Michael

[Michael Lasseter]

I tried the hammer technique on the metal part of the pump housing. Why not, it wasn't working?   After about 30 hits with a small ball peen hammer, the pump motor came up to speed.  I let it run for four hours, starting and stopping it periodically.  I will be surprised it it doesn't fail soon but right now all is well.