Lennox Electric Heat and Air, Heat won't kick on

[BigDave]

I have all electric out in the country which is great at times, others not so great.

The heat has not been coming on recently when the thermostat dropped below the set temperature. The other night I opened the closet the Lennox E16Q3-20-1P unit is in and moved some things away from the wiring that goes to the thermostat and walked off - suddenly the heat kicks on. It has worked for a few days following that but now it refuses to come on, woke up freezing at 4 am.

I reset the termostat settings and set the thermostat so that the AC should come on, and it did come on correctly. I have had the line from the outside unit to the handler, or the thermostat replaced before - was same problem with AC not wanting to kick in and run. Funny how many details you forget in a year or two, but at this point it seems it would have been prudent to replace the one from thermostat to heater / handler as well. But you know, if it ain't broke don't fix it may have ruled the moment's decision.

So what I have is AC that operates off the thermostat but heating that won't work from thermostat to the same handler or what ever it is called. I don't have any gauges to check the line and if I did I am not sure what I was looking for. Seems like I have narrowed the wires down to 2 wires. Another odd thing I never noticed before is the transformer inside handler hums constantly (nice to know it is alive) but should it be?

Any help is appreciated
Cold Dave in the sticks

[BigDave]

After checking the thermal fuse, I discovered someone, probably the last guy out that serviced the unit, had placed thin aluminum foil round the thermal buss fuse. After checking the fuse it was blown, and probably his aluminum foil was acting as the buss. I got a few fuses and got home at midnight, replaced the fuse, turned on brakers and man the heat and fan popped on just like they should. My wife looked at the thermostat at said 71 was too high for her and backed it down to 68, then we turned off the space heaters, went to bed. IN the morning the space heaters were back on and she informed me the heat never came back on.

Now I am back to the fan will blow when turned to on at least, so the fuse is still good. Getting discouraged here, since it initially kicked in just as it should when I first replaced the fuse. (Please tell me to resist putting the aluminum foil back on the fuse).

[Hube]

Are you sure the unit's fan,and /or element is not on another circuit (fuse ) that has blown? What AMP rating is this fuse you replaced? At any rate ,DO NOT put foil back in place, as a fuse is there for protection. You say the fan still works on this unit, but the heat coil does not. Check out the coil. Check for broken wire to element. Check junction of fan and coil wires in the unit. Hube

[BigDave]

The heat and fan kicked on last night when I initially replaced the fuse when I finally got home at midnight. All seemed well. But when the wife turned the temp down it never did kick back in. The fuse is 3.2 amp 300 v.. got it from a lennox part dealer luckily, on the way to work. Have to check the wires and all later but it seems it an intermitent problem (except that now it is mostly off)... thanks for suggestions.