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Heat not working

3K views 29 replies 5 participants last post by  beenthere 
#1 ·
Hello all:

Iam having a problem with a Magic-Pack unit. I had a service technician out and he coudn't fix it. I'll try to describe the problem as best I can.

Heat was working with no problem. Now it very rarely comes on, but occasionally does work for a short period of time and then it shuts down. I have turned on/off the emergency reset switch, changed the batteries in the thermostat, turned off the thermostat,raised the thermostat to a high set point.

In all cases either nothing happens, or the blower runs for a short period, the gas burner might fire, but then it shuts down. There is clicking out at the unit as it seems to be trying to start up. I just tried setting the fan to run constantly and nothing happened. The unit was installed in March of 2009. 48000 BTU, Honeywell electronic thermostat.

I'm thinking of replacing the thermostat, least costly option, since it cost me $110 for a technician to change the batteries in the thermostat. They were my batteries. Any help would be appreciated.

Thanks,
 
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#2 ·
Carefully remove and label the thermostat wires at the circuit board inside the unit. Then put a jumper wire between R and W and run the unit. If it runs normally then the tstat is the problem.
 
#3 ·
Yuri,

Thanks so much. I turned off the main switch to the heater, spliced the R and W wires together and the heat started up but shut down again. And then restarted.

I did leave the R and W thermostat wires connected when I spliced the R and W together. I will disconnect and see if that changes things. Any other thoughts?

Greg
 
#4 ·
Yuri,

The heat shut down. Now it is calling for heat again, but never ignited. LED gives 3 flashes after it tries to fire indicating a problem with the pressure switch. Then it tries to fire up again. Now it just fired up. Shut down again calling for heat. Fired up again. It's running. I took out the filter to make sure there were no air restrictions.

Greg
 
#6 ·
Follow the hose from the press switch to where it attaches to the collector box or ventor fan and pull it off. The ream the hole out with a small bit or paper clip. Bit is better. Blow the hose out with it detached from the switch, may have moisture in it. DO NOT suck/blow into the switch. Check the grill outside the condo for debris blocking it.
 
#8 ·
Damn heater has been working all day. I am getting 24 volts at the pressure switch so it's working. The hose is clear so no clogs there. I'll detach it and blow it out.

It's real tough to get to the grill. I'm up on the third floor but I'll see what I can do to check for blockage.

Thanks,

Greg
 
#12 ·
There does not appear to be any blockage from the limited access I have. Tested p switch across the two wires and got no voltage. Tested each wire to ground and got 24 volts. Furnace was running during testing and as soon as I put the panel back, it shutdown. Starving for air? Ist worthwhile to pull the vent tube off completely and check for a blockage?

Thanks. Greg
 
#18 ·
The pressure switch could be weak and fluttering. If it has a rating on it like .47" WC and you buy a manometer you can check the draft thru the unit and know if it is enough. The ventor fan motor could be slowing down or have a bad wheel like Beenthere said. I would replace the pressure switch and try it rather than buying a manometer etc. If there is no rating on it then you have to try dig it up or call a tech with some experience on those units.
 
#20 ·
I just want to provide an update. And ask a question about what I now believe is a solution. First, I used everyones knowledge and thoughts to get to this conclusion, and for that I am grateful.

First, I did not replace the p switch. I didn't get the chance to do so. Second, I thought about the issue and every time that I took the door off the heater would work, usually, briefly.

So, this morning I had an inspiration as I stood in the utility closet, trying to start up the heater. I took off the blower panel and replaced it with a filter. The unit is running and, hopefully, continues to run.

So my question is, is there any downside or more importantly any danger to doing this?

Thanks,

Greg
 
#22 ·
If the unit catches on fire you will be liable for the deaths of the other condo members. The unit is designed to run with that door on. Voids the UL and AGA ratings w/o it on. Some of my other techs are finding quite a few of those units with cracked heat exchangers. May be time to call a Pro.
 
#24 ·
Next step will be to find the right pro. I did initially call a pro. He changed the battery in the thermostat and charged me a $100.

Here are his verbatim notes:

Found heater shutdown on high limit, amp meter 1.2 amps no fire dampers closed. Heat losing signal from T stat for blower changed battery in t-stat cycled heater heater working ok at this time.
 
#25 ·
Not the right Pro. Lots of techs rarely see those units (not that common) so I would make sure whoever you call does have an experienced one on those units. If they sound vague on the phone then call someone else. Ask for the service manager if they are a larger co. and see if he can send his best tech after you tell him the details.
 
#26 ·
Yep. Not a good tech.

Around here. A customer calls you back to fix it for free(labor wise) if you charge them and it isn't fixed the first time.
 
#27 ·
Yeah, I don't see the point of having an incompetent tech or a company who sent them try to fix it again.

My wife wanted to do just that call them back. I am determined, and through, your help to fix it myself.

Or at the very least I'm more prepared to find the right tech.

I couldn't have got this far without you guys. I feel like at least I have eliminated some things that are not wrong, like the thermostat, which by the way, was the tech's next suggestion. He never thought to bypass it and eliminate it from the equation.
 
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