Trane XV80, W R 1F91W-71 Please help!
Greg Hughes
Friday night something strange happened with my heating system, and I
am trying to find out why. As stated in the Subject, the unit in
question is a Trane XV80 with A/C, and the thermostat is a two stage
White Rodgers 1F91W-71. Furnace is 1 1/2 yrs old and stat is 8 mos
old.Both working flawlessly until:
System was on, but too warm to kick the heat on. Stat was set at 65
and fan was set in Auto. My ma came to visit, and was cold, so I
kicked it up to 68. When I returned a few hours later, I noticed that
the house was cold, and the blower was on, blowing cool air. The stat
indicated both stages of heat active. (LED's both on). I went to the
basement and saw that there was indeed no fire, and blower was on, I'm
quite sure it was high. I looked at the diagnostic LED on the furnace,
and I THOUGHT it was blinking nine times. I then turned the power off
to the furnace, waited a few, then turned it back on. I had a Call for
heat, the ignitor lighted, then dimmed. It would cycle like this every
minute or two. I then noticed a two blink error code,(External
Lockout, Retries or Recycles exceeded.) I tried this a few times
cycling power in between. I noticed I never heard the relay? kick in
which normally releases the gas? It had perhaps a VERY small amout of
gas odor coming from the furnace. While the furnace was trying to
start, I gave the gas valve a light rap with my knucles, and it
started up! I tried a few startups and everytime it started.
I proceeded upstairs and looked at the stat. I turned it off and back
on, and it kept going directly to two stage heat, bypassing the first
stage. This is a first. The furnace is now firing, but stat giving
order for two stages of heat, with only one degree of heat needed.The
stat is still on HOLD function.(Even with ten degrees needed, it
ALWAYS spends a while in first stage heat, before kicking into stage
2). I then removed the stat faceplate, and changed the battery. I
replaced it on the wall, hit AUTO to cancel the HOLD function, and
everything now appears to be normal. I am quite sure the battery was
good, but perhaps cancelling the HOLD mode cleared the two stage
problem up.
Any insights?Do I need a service call, and what do you suppose
happened? I have a ten year warranty, but I don't want to get someone
here needlessly. Do gas valves stick sometimes? Even if the valve
stuck, I don't understand the behavior of the stat. Can anybody shed
some light on the situation? I'm a troubleshoooter at heart, and I
would like to understand what happened here. Thanks a lot for any help
(advice) you may have!
Greg
John Mills
I have the same furnace with a 1F92 which is virtually identical. Never
seen such a thing. I've never had the stat go straight to 2nd stage. I
don't recall what 9 blinks is, I have the older board which doesn't go
that high. I'd guess something funky in the furnace not the stat but who
knows. See what the 9 code is.
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Greg Hughes
Perhaps I was looking at the wrong LED, or miscounted, or something
weird is going on, I counted it twice, though! After that, I got 2
blinks.
Greg
sljones
The 9 flash fault is a fairly common one on the older Trane furnaces.
They've even issued a service bulletin on it.
It is caused by the electrical signal to the control board.
In most cases re-grounding the furnace will solve the problem.
If the line voltage to the furnace serves anything else, there may
be a certain amount of "noise" in the electrical line to the
microprocessor, causing the fault.
The simplest cure is to reground the unit to
drain off the excess "noise".
Another option if grounding doesn't work is to add
a capacitor to clean up the line voltage.
When you tapped the gas valve you probably reset the ground,
which is pretty common, but the problem will probably come back.
good luck
s l jones
st. paul, mn
"Greg Hughes" <ghu...@usa.net> wrote in message
news:k1ikhts807r5kb1k1...@4ax.com...
Steve Bukosky
>Hello everybody.
>
>Friday night something strange happened with my heating system,
The fault code nine is triggered by either a bad igniter, bad ground
or low incoming voltage. It can also be triggered by electrical line
noise from anything from a floating ground, doorbell transformer,
computer network, light ballast and probably a few other things I've
not run across. Your furnace running on high fire might actually be
the thermostat staging to second stage. Depending if W1 and W2 are
made together or staggered a few moments, the furnace will either run
10 minutes in low fire or could run as little as 30 seconds in low
fire and then go into second stage. I don't have the particulars of
your W/R IF91 here so don't know how it reacts to an immediate call
for both stages. The fault 2 is a failure of ignition and from the
sound of it, could be a gas valve issue. Some W/R gas valves had a
problem with the connection at the top of it. You might have one of
the affected units. I would have your dealer compare your serial
number to the bulletin that was issued a year or two back. If you
have not had a yearly checkover of the unit, one should be done paying
special attention to the grounding and the adjustment of the igniter.
There is a special method for checking the ground and electrical
noise. If your dealer is not familiar with it, they should discuss it
with the Trane field service representative at the distributor that
sold them the furnace.
Steve Bukosky
Greg Hughes
Greg Hughes
Greg Hughes
Greg