I got a new thermostat - a cheap Honeywell (a builder installed it). I find
the house gets too cold before the furnaces switches "on". And, the furnace
switches "off" before the house reaches the set temperature. I think I need
to adjust the anticipator. Could anyone help me?
the anticipator creates a small amount of heat in the thermostat when
the furnace is on..
but it cannont help for your first problem,,, that sounds like the
temperature setpoint needs to be adjusted...
the anticpaitor can adjeust the amount of difference in degrees between
heat on and heat off...
but per your description, the difference is ok, its just that both are
so first try to adjust the temperature calibration, after the turn on
is working correctly then we can talk about the anticipator to adjust
the turn off.
Is it the ultra-basic little round one?
Their thermometers are often way off. For a given setpoint, the temp at
which the mercury switch actually makes is highly dependent on how you
mount the stat on the wall- turn it a few degrees and all bets are off.
I'd suggest monitoring the actual temp with an accurate thermometer-
couple bucks for various types at most plumbing/hvac suppliers. Maybe
Radio Shack? Then see if the stat's behavior is consistent, and vary
its set point to match what you want, as accurately measured.
Is your stat locked or something, that you might not be able to change
setting? Extra sweater is much less wasteful than burning oil,
The advantage to the round ones, you can 'calibrate' it by rotating the
whole darn thing slightly to move the _actual_ setpoint up or down
relative to the _indicated_ setpoint.
Well, you can do that with any merc-switch thermostat, but the
rectangular ones look a little silly cocked sideways...
No you don't, it sounds like it works fine just
the index is wrong, i.e, 68 degrees on the setting
is actually 65 degrees or so.
However, if you really want a better thermostat
get the $39 Honeywell digital (Lowes has them on
sale but shows the wrong picture, it is really a
rectangle). I've had mine for over 6 years and it
would keep the temp at the thermostat within one
degree on an electric furnace and now on a gas
Builders dont install em..they just want cheap..so the installers put em
If its a T87 Round One..its the best thermostat Honeywells
built..period...if its out of calibration, teh little tool they have makes
it a simple thing to adjust..
Your problems NOT in the anticipation setting.
Bet that suckers a mercury switch round unit, and its not
level....yes..there are level indicators on it...take the outher ring off,
take the stat off..three screws recessed in it..and at the top of the sub
base there are two tits that are for placing a level across...right below
the fan and mode switches.
Hi CB. A few years back I ran into something wierd on three T87's.
Somethng happened to the mercury in the bulb-- instead of being a shiny
silver, it was a grey that looked more llike molten lead, and flowed
like lead. Normally, as soon as the bulb moves just past level the
mercury rolls freely to the lower side. In these cases, the mercury
wouldn't move either way until the bulb was at damn near a 45 deg angle.
For the amount of temperature control that gave, they were more of a
toggle switch than a thermostat. The first one I saw was on a wall
heater. I had installed the stat the fall before, so it was replaced
under warranty. The other 2 were on central a/c-- age unknown, probably
5- 10 y/o. Both of those calls were in a/c season as I recall. Funny,
never seen anything like that on any other mercury bulb stat, and never
seen another one since the last of those three, about 7 years ago more
or less. Larry
If you want increased efficiency with gas and oil furnace heating you
are better off without close tolerance heat anticipator
settings, as keeping the temp variation close causes more cycles with
increased energy losses while the heat exchanger(s) are heating up.
Longer, but fewer, run-times will increase efficiency. If your family
dresses a little warmer they won't notice the temp variation.
I keep the temp low and the run cycles are very long with a lot fewer
cycles. (Experiment a little.)
PROPER A/C UNIT & DUCT SIZING ESSENTIAL for EFFICIENCY & BTUH PERFORMANCE
This is Turtle.
I do remember this problem but mine was on a White Rogers Rectangle
standard gas / Electic combo type WRXXXX444 thermostat. this was on a
new one out of the Box on about 3 of them about 15 years ago. they
would wait for ever to switch then when they did switch they would
bounce back and forth and short cycle the compressor with out a time
delay on the compressor. the reason they were doing this as persay the
Factory Rep. they had put too much mercury in the bulb which would make
it really fly over when it did switch. The Warehouse had about 2 Gross
of them they sent back to be replaced. This is the only time in my life
i ever seen this.
Ran into maybe three total like that...one wasnt in a Honeywell..it was some
cheapy china thing that looked like a Robertshaw, but was WAAAAY cheaper.
I like the T87s, but at least with a digital higher quality stat, you can
eliminate alot of issues down the road.
On another odd note, had a good customer of mine call this morning..has a
Payne unit that so far has about been rebuilt, but he wont replace it..yet..
Said what was going on, was his nice "high quality" Totaline stat was
reading AUX no matter how he turned the heat on..
SWORE the outside unit was running.
Long story short, outside wasnt running. Compressor lead had broken loose
and was rubbing on the suction line on the heat pump..insulation wore off,
tripped the breaker, and the resulting hole, of course, tripped the LP
switch.....damndest thing I had seen so far this year. Once it was repaired,
vac;d, charged, and running, no more AUX...Im still trying to figure out how
it was knowing the comp was out, yet, no L wire, and thus, no feedback to
This is Turtle.
If you would like. Give a picture or a model number of this thermostat
and i will get with you on setting the antisipator. you may e-mail me
or post here but you need to know first what type system you have and
what thermostat you have. You could have the wrong thermostat for the
system you have. Post or E-mail this and get started. Now some here may
want to bull you here so watch what you get into with. My E-mail Addy
here is good.
Why dont you simply tell him that he needs to look on his gas valve, read
the anticipator setting posted on it, and then, remove the round cover of
the stat, look on the anticipator, and slide the pointer to the same
Even you can do it.
Thanks, TURTLE - I've replaced the new thermostat with the original one
(Honeywell t86a 3006) because I can set the temp when it's dark. I have
a Lennox G27M(X)-1 furnace.
There are two wires coming out of the wall to the thermostat which I'd like
to replace with a digital programmable one.... nothing fancy.... my wife
wants to wake to a warm house. Any suggestions
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