"Tony" wrote in message
...
OK, this POS doublewide has straight electric hot air heat, A/C, but no
heat pump. (Coleman Evcon) Years ago when I first moved here I closed off
the ducts to almost 1/3 of the house (two bedrooms and a bath) that are
only used when I have guests. At the same time I set the fan motor down
one notch for each mode so there wouldn't be too much pressure and I'd
loose heat & A/C out of duct leaks.

When the thermostat called for heat, the fan would start immediately,
blowing cold air before it had a chance to get warm. It would run at what
I'll call medium (not high because I stepped it down a notch). When the
thermostat opened, the fan would slow down to low, and it would run a
little while until the heater cooled down a bit then it would stop.

The A/C would also run at medium, not on high. I liked it that way
because it wasn't enough to freeze the evaporator, but it did dehumidify
the air much better than on high.

So my thermostat got screwed up (worse than it was already) from me trying
to adjust it so 70 degrees is really 70 degrees. It was worse, setting it
at 75 degrees yielded a temp of about 70 degrees.

Today I installed a new 4 wire thermostat to replace the old 4 wire
thermostat (child's play). I first made sure the proper color wires went
to the proper terminals on the old one. Yes, that was correct. I removed
it and installed the new thermostat with the wires to the proper
terminals. (Yes I adjusted the heat anticipator to .3) Now when it calls
for heat, the fan doesn't run until the heating strips are getting hot, so
that blast of cold air isn't nearly as cold or as long as before! Great!
Wonderful!!! But how did this happen?

My only guess is that a temp sensor in the heater wasn't working and it
just so happened to start working now, using the heat for the first time
this season. I can't think of anything in the thermostat that could have
"fixed" this problem.


The fan should be controlled by a thermal device in the plenum so as not to
blow cold air. It appears to me, that the old stat sent power out on the
green terminal whenever it called for heat. This would cause the blower to
run immediately, but when the stat was satisfied, it killed power to the
heating elements and the "g" fan circuit, allowing the thermal device to
allow it to run in cool down mode, then go off. Don't you wish you changed
the stat 30 years ago