On Thursday, January 22, 2015 at 10:12:45 AM UTC-5, philo wrote:
On 01/22/2015 09:05 AM, Tony Hwang wrote:
philo wrote:
On 01/21/2015 09:08 PM, bob_villa wrote:
On Wednesday, January 21, 2015 at 8:58:09 PM UTC-6, philo wrote:
I've got a Trane XV-80 furnace that just tonight quit.

When starting the ignitor /sometimes/ glows but most of the time does
not...and either way the furnace does not light.

I can light it manually with a match and it will run normally.

The ignigtor appears to be OK...no breaks and the resistance is 130
ohms

What voltage do they operate at and is it AC or DC?



Looks like it must be the controller itself and I know that is going to
be expensive.

How old is the ignitor? The resistance sounds right and its AC. You
may have a solder break on the controller relay, giving you the
intermittent.




The ignitor is maybe 8 years old and I took it out and it looks good...

When I turn the furnace on, at the time the ignitor should be glowing
I'm only getting 4 vac at the leads which I know is too low to make it
glow.


My guess however that it needs more than 24 volts as I applied 24 volts
to it and it only got very slightly warm
Hi,
Most trouble part of a furnace is HSI and flame sensor. HSI needs
replacing, flame sensor needs cleaning. HSI is like ~40.00 or so.
I'd just put in a new one and see. I always keep spare HSI, one at home
abd one at cabin. HSI is like big filament in a light bulb. With
age it won't produce high temp. It has to glow real bright red when it
is on. Worth checking loose connector too. You can tighten the connector
female pins.



Yep went through everything...

the controller does not supply voltage to the ignitor (except if furnace
is left off for a few hours, then it sometimes works)

Don't want to risk repairing the control board, this being winter...
as the furnace does work now if I light it manually.

Local supplier does not have the control module and it would be quite
expensive. ($470 )

Since I was going to replace this 23 year old furnace this year anyway,
might as well do it now.

Many folks here recommended Goodman, so I am having the local deal stop
by and estimate the job in about 4 hours.



It it costs no more than two toilets I'll get it done.


(This summer a plumber told me it would be $2000 to replace a toilet
that I replaced myself for $80)

I replaced my old Ruud with a new Rheem. Very happy with both, they
are made by the same company. The Ruud went 27 years, only needed to
add a hard-start kit to the AC. Rheem's been in 3 years now, 93%,
two stage, variable speed blower. Really surprised at the fuel savings,
probably 40%+. I was expecting a decent improvement, but that was
more than I hoped for. I'm really a fan of the two stage concept too.
At full output, I can raise the temp 6F an hour. That lets me get
the house back up quickly after being away. It runs at low stage when
maintaining the temp, ie most of the time. Without two stage if you
want a bigger furnace to be able to heat quickly, then it's not going
to run as much as it should to move air around, etc when it's just
maintaining.