Weather King/Iceco/Rheem model # 17AHJ11S020C01

[patrickA]

Hey Guys, I'm going to give as much info as I can although I'm no appliance guru as some of the resident techs here. As you can see from the topic subject my heat pump air handler is a 3.5 year old Weather King/Iceco model # 17AHJ11S020C01 which is apparently made by Rheem I'm guessing from the warranty package. Anyway about two weeks ago I had lost power to my non-programmable thermostat (digital). Being a plumber and not an hvac whiz I jumped to conclusions and replaced the thermostat with a programmable type. Well that was a waste since I went down to the crawlspace and popped the cover off of the air handler control and discovered the transformer was blown (black burn marks around the plastic covers). I was unable to pull 24 volts after the transformer. I searched for shorts or loose wires but found none. I installed a new one and it did not work. I found a repair shop where we pulled an old transformer out of a scrap unit in the back and it worked fine. I had heat and AC. Now two weeks later, I have to use the heat but it wont come on. I can turn on the AC and the fan, but setting it to turn on the heat does nothing, no fan or heat. I never did figure out why the first transformer blew but we did have an electric storm days before I noticed it was off. Anyway, while I was installing the new transformer, I checked for continuity at the sequencers and the heating elements and everything checked out ok. I was also able to pull the correct voltages also.

 So Before I go clammering back down through the crawlspace what should I be checking for in the air handler/heat pump to find out the cause? Since there is no fan or heat when the thermostat kicks on, is it possible a sequencer may have died?

:?

I'm all ears.

-Patrick

[dkpd1581]

First things first...the T-stat you replaced, was it designed for Heat Pump operations?  If its a universal style, did you configure the Builder's Setup Menus for Heat pump (versus Gas or electric heat only).

Secondly, electric strip heats in a HP application are primarily Stage 2/Aux/Emergency heat and are also engaged in the defrost cycle.  They will not engage sequencers unless the Stage 2 heat engages, Emergency is selected, or you are in defrost.

HP heating first stage is a compressor call (Basically a Y1 call).  So if a Cooling call energizes the outdoor unit, the contactor closes, and the suction line is cool and the indoor fan runs, put in a call for heat and see if the outdoor contactor closes and the suction line now becomes hot.  If not, follow the 24VAC wiring to the AH in the crawl space and check to see if you are getting 24VAC down the line from the stat to the board. You may have a wiring issue at the t-stat sub-base or a configuration problem.

Make sure you have a Heat Pump and not a Fan Coil with Electric Strip Heat only.  Go out to the condensing unit and look straight through the top of the fan cover and verify that you have a Reversing Valve.  If its a Fan Coil with Strip Heat then we have another road to travel. 

Since its a Rheem/Ruud make, verify if the reversing valve coil is energized in the Cooling Mode (the one mode we know for certain works). Most likely the reversing valve - for Rhem Ruud - energizes in Heat calls.  Put it in AC and see if there is voltage applied to the coil of the Rev Valve or not.

Get back and let us know.

[patrickA]

dkpd1581, Thanks for responding to my inquiry. It seems after reading your response I had an error in my t-stat settings. I installed the Honeywell RTH7400 t-stat from the Honeywell T8411R. Apparently the setting I had it at did not allow the option to control the reversing valve therefore the heat would not kick on.It's back up and running now. I had managed to get some heat to come on last night (emergency heat) but not through the heat pump. I can't wait to see my power bill after that :headbang:. Anyway thanks for the help.

-Patrick