Carrier control board HK42FZ011 & HK42FZ013 - http://www.hvacmechanic.com/ Forums
Original message
| intrepid
 |  "Carrier control board HK42FZ011 & HK42FZ013"
, posted Thu 26 Oct 14:05  
I am having problems with a Carrier weathermaker 8000(58XMA) that was using the plagued control board HK42FZ011 until just recently when I replaced it with the HK42FZ013(325878-751 Kit). The control board is also operating an electronic air cleaner, humidifier and a honeywell programmable thermostat. At the end of the heating season I had to replace the humidifier because it corroded so bad that it was not worth fixing or repairing. I replaced it with a another Carrier unit that was suppose to replace it, P110-LFP1318A, and was working with the HK42FZ011 control board. At the beginning of this heating season, the heat cycle failed to start properly, blew the 3 amp fuse on the board. Replaced fuse, and still it will not turn on the gas valve. I let the unit stay off for 24 hours and got it to start and watched it cycle 4 times and thought things were now working. Then it failed again without giving an error code. So I replaced the control board with the recommended replacement board, HK42FZ013, and started it up. It blew the 3 amp fuse on the start of the heat, the gas came on and then the fuse went and gave the error code for a short in the 24 v wiring. When the humidifier is disconnected, it will cycle just fine, as soon as the humidifier is connected, it blows the fuse. I checked the wiring of the humidifier and read 700 ohms resistance which means it should be drawing around 33-35 ma of current. From looking at the schematic it shows the relay closing on the board and delivering 24 VAC to the humidifier which in turns is suppose to turn on the humidifier. Now is there something wrong with the humidifier that wasn't mentioned in the installation manual? Do I need to use an isolation relay, i.e., seperate relay and 24 VAC power supply to turn on the humidifier? Are these control boards properly protected from transients and spikes on the power going into them? The only thing I haven't done is take apart the humidifier and see what type of control circuit they are using that might cause the problem. Also, when I apply 24 VAC directly to the humidifier, it works fine.
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Replies:
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| nitronorm
| "Re(1):Carrier control board HK42FZ011 & HK42F" , posted Thu 26 Oct 21:31
you have a short in the wires some were start looking for it. take one wire at a time and see if it ground. check the stat wires to see if it shorted or if some thing rubbing. the only thing new about the board is that they took the black cover off due to the resistet to the inducer motor were getting to hot and burning up.
sheet metal local #104
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| acefurnacefxr
| "Re(1):Carrier control board HK42FZ011 & HK42F" , posted Thu 26 Oct 15:52
what do the instructions for the humidifier say as far as powering it up?
My spelling sucks thats why I am not a teacher.
22 years of running HVAC service calls Man I have seen it all.
I belong to a union
I also belong to a gym a campground and Triple A.
I may tell you whats wrong but its my job to fix it not yours.
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| | intrepid
| "Re(2):Carrier control board HK42FZ011 & HK42F" , posted Fri 27 Oct 18:05
That is where the problem is, the new humidifier requires a 24 VAC relay(HN61KQ120) because the humidifier is looking for dry contacts to switch it on and off. So frustrating that this unit was to be replacement and is nowhere close. I had to make changes to the mounting of the humidifier because the new one requires a different size opening in order to mount it. I will get a relay and new transformer to mount on the humidifier since the old transformer got warm and is not working. Will let you all know how it goes.
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| | Intrepid
| "Re(3):Carrier control board HK42FZ011 & HK42F" , posted Mon 19 Feb 02:13
Just thought I would update everyone who was interested in the final outcome. I had to rebuild/replace the transformer on the humidifier and still not working correctly. Checked and found that the coil on the water valve solenoid was bad, it was cooked. So knowing I was not going to find a replacement coil, I went and bought the 32 gauge magnet wire. I unwound the old coil and rewound it with new wire and it works fine, or so I thought. When I put the unit back together and hooked the water up, still nothing is happening. The valve opens and closes but no water flowing. So I take the whole thing apart and finally found that there is an oriface to control the flow rate of water, a little red peice of plastic on the outlet side to the pipe. It was all plugged up with sediment and so I found a straight pin and cleared the hole. It works like a champ now... Now why doesn't totaline just include the darn relay and save the installers trouble down the line.
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