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.