Trane XR80 Furnace Issue

[avoidablehinder]

Hi. I've got a weird issue with my Trane XR80 furnace.
I've had two different companies come out to try and
diagnose the problem without success. One of them is
very familiar with Trane products.

So, here is the problem. I've noticed that sometimes
my furnace will partially come on without the burner
and blower motor coming on. I hear it turn on
(exhaust fan maybe?) and go for a bit and then it
goes off. It will immediately come on again and do
the same thing. One early morning I noticed it did
this at least 5 or 6 times. I've even noticed this
happen when I have my thermostat set for AC!

The furnace will come on as it should at times and
properly heat my condo. I'm just afraid this is
especially taxing on my furnace and may cause it
to fail in the near future. I was trying to be proactive
to get this checked out before I really need it this
winter here in Colorado.

Anyone have any idea what is going on here?

Thanks for your time,

Jon

[pecmsg]

Unfortunately you haven't found a qualified contractor .............Yet!

Keep looking, measurements need to be taken, with those they will be pointed in the right direction.

[mgenius33]

What did the 2 other contractors repair?

[pecmsg]

What did the 2 other contractors repair?

An Invoice?

[avoidablehinder]

An Invoice?

Thanks for the responses.

The first guy that came out seemed to think it was the thermostat. He
suggested I replace that. He didn't charge anything, which I appreciated,
but I'm not so sure his solution will fix the problem.

The second guy charged me a $ trip fee. This is what he wrote on the
receipt (hope it's ok to list what he wrote): Homeowner reported an
occasional failure to fire. Ran System. Pressure switch closes at .50inwc.
Inducer is pulling .70 inwc. Flame signal 3.1-3.5 dcmA. Inlet:7.2
Manifold: 3.6 Drop: 0.7 (think it is 0.7, a little illegible). Ran water heater
during heat cycle. Inlet pressure went down by .3inwc. No delay in
flame crossover. No loose wires on the gas valve, pressure switch, inducer
motor or board. HSI ohms: 16. Showed the homeowner how to look for the
glow of the HSI. Cycled the system 15 times with no failures. If the issue
returns the homeowner should pay attention to outdoor conditions/time of
day so that we can better find the issue. Unfortunately I am unable to
reproduce the failure at this time.

When I noticed the issue when it did the "partial run" 5 or 6 times -- the
temperature was in the late 20s/early 30s with no wind. I believe the
thermostat was set to 68 and the current temp during these partial runs
was 67. A few times I have manually increased the thermostat a few
degrees higher and the blower would come on ok.

Is any of this information helpful in the diagnosis? I honestly don't know
what to do other than try and hire some other people to come out.
Afraid they will be unable to locate the issue too and I will be out more
money. This second company is highly recommended on Team Dave Logan
website and Dave Logan endorsed (Denver metro recommended providers).

Thanks again for any help people can provide.

Jon

[pacnw]

What thermostat?

[beenthere]

Sounds like a Nest thermostat wired up to steal power..

[mgenius33]

Tell your tech to get on this site and contact us. I believe there is a common issue with ignition timing sequence failure on this particular model when it gets to be several years old. This is one of those "out of the ordinary" issues. I agree, it can be a pain to diagnose when everything is working properly for 15 cycles. It sounds like the second tech did his job.

[avoidablehinder]

The thermostat I have is the Lux TX9600TSa.

I had a honeywell (I believe) for a bit and noticed this issue. My Dad had just
upgraded to a Nest and asked me if I wanted this one, which was not very old.
I installed it and noticed I was having the same issue, so figured the thermostat
was not the issue (unless the Lux is malfunctioning).

[beenthere]

The Lux is battery operated. So I am guessing you don't have a low battery warning showing on it.

[avoidablehinder]

Tell your tech to get on this site and contact us. I believe there is a common issue with ignition timing sequence failure on this particular model when it gets to be several years old. This is one of those "out of the ordinary" issues. I agree, it can be a pain to diagnose when everything is working properly for 15 cycles. It sounds like the second tech did his job.

I believe this furnace is about 12 years old, so wonder if it is on its way out. Do you think it is too old? A couple years ago the flame sensor and run capacitor were replaced. Last year a tech replaced the blower motor.

[avoidablehinder]

Thanks everyone for the replies!

[avoidablehinder]

The Lux is battery operated. So I am guessing you don't have a low battery warning showing on it.

Don't see a low battery warning on it. Put this in a few months ago with new batteries, so should be good for a while.

[pecmsg]

I believe this furnace is about 12 years old, so wonder if it is on its way out. Do you think it is too old? A couple years ago the flame sensor and run capacitor were replaced. Last year a tech replaced the blower motor.

Aren't you the one that's suppose to make that decision!

[pacnw]

NEST is not considered an upgrade to most on this site and in the trade!!!!