Hi, I have a problem that has stumped me and I can't find a good
previously posted thread about it.
My house has forced air heating and a run of the mill, standard round
mercury thermostat. At the beginning of the day when I wake up, the
temp will be really low in the house (I have seen it drop to below 50
degrees). I then turn the thermostat all the way down to 0, then back
up to 70. The forced air furnace then switches on and starts to heat up
the place. It stops when it gets to about 70 and then it shuts off
again until I manually "reset" it.
-Cold in Montana
I doubt it is the thermostat, which is just a temperature controlled
switch. Sounds like a circuit board is getting a safety lockout. You
will probably need to get a service tech to check it out. But go ahead
and try changing the thermostat first. If it turns out you need a
tech, put the old tstat back on, so he will only have one problem to
troubleshoot. Make sure you write down a wiring diagram showing the
Go on, get ya one, but its not your problem.
You have a board going into a soft lockout.
You need to find out why.
99% of the time, its NOT the thermostat. The thermostat has already proved
to you it works, and works fine..
its nothing but an ON-OFF switch....period.
Well hell..if thats the case, I got this really nice, PC controlled deal,
that will also call, page, and even FAX you when the unit starts to get a
problem. It can also call, page, or fax the contractor of your choice to let
him know your units about to take a big dump on you.
Hey..its wireless too if you want it to be, and even comes with a really
nice new Honeywell stat.
Think that $1500 setup will cure the fact hes prob got a 90%+ unit thats got
a clogged drain on it?
Yea do you have those instructions CBHVAC? Maybe you cound come out to
my house in MT for a looksie?
Oh I fixed this by the way. NOT A PROBLEM WITH THE THERMOSTAT. So that
camp was wrong on this thread. It was the board. I jiggled some wires
and now it circulates and heats as it should. Great unit. Very happy
But if someone has the calibration instructions and wants to help me
with this over the phone... that would be great. I could give you a
God no...do 100 of them and who needs an instruction sheet?
But, you have to have a wrench that Honeywell will be glad to sell you for
about $5, that may, or may not come with an instruction sheet.
its simple..you take a temp reading, if the thermostat is correct, you check
level on it and then, if thats good, you dont have an issue.
If the stats wrong, you put the wrench on the springs c clamp and calibrate
it to the correct temp, level stat and your done.
Jigglin wires normally aint a fix...find out WHY you had a bad connection
and where. Grounds are notorious for going bad on those and if you have one
fail at the wrong time..
I never understood that. I don't give a damn what numbers are
showing on the dial. I turn it up until I'm comfortable, and then
stop. If I have to crank it up until it says 83 degrees,
that's fine by me. If I want to know what the temperature actually
*IS*, I'll look at a thermometer.
We switched to programmable a few year ago and wondered why we waited.
Brand name rep suggested Sears as source and ignore their logo on it
so I took a DEEP breath and went into their store and got it. Don't
remember the brand. Maybe White Rogers?
On 12 Dec 2005 16:02:57 -0800, email@example.com wrote:
Instead of turning the thermostat down when it seems stuck, try
turning it UP. If the furnace comes on, THEN you will know it is a
If turning it down and then back up is the ONLY way to make it come
on, then others are right when they say you have a board problem (or
a soft lockout). In that case turning it down and then back up sends
an OFF signal followed by an ON signal to the furnace, and that resets
the furnace controller. --Phil
Phil Munro Dept of Electrical & Computer Engin
mailto: firstname.lastname@example.org Youngstown State University
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.