Harmon Accentra Insert vacuum switch new, nothing happening

[abcd61]

My Question is:

Plug in the unit. The power, status and combustion blower lights are on. All others off.
I bypassed the vacuum switch and the stove appears to then operate normally. So I assumed I needed a new vacuum switch. I purchased that and installed it. That resulted in no change, and I am back to The power, status and combustion blower lights are on. All others off.

What would you recommend I try next ?

 

[johneh]

If it works with vas switch bypassed then the obvious conclusion is no Vac.
Check vav hose for holes, cracking etc, check the door and ash drawer seals
Dollar bill test check vac nipple for ash plug Is the stove and exhaust pipe clean
All Passages. Does the combustion fan-run and is it clean?

 

[abcd61]

Thanks for the reply.
The combustion fan does not run. I am curious how there would be vacuum when you first start up. Since nothing is running, there is no vacuum. Then you turn the stove on and fans start up etc, so the vacuum switch must have some form of delay or something before it turns off the fans. In that case, why dont I see the fans turning on at least for a few seconds ?

 

[Overfireinthehole]

If your combustion fan isn’t running when the combustion light is on the pull the motor see if it’s locked up. If it’s jammed unjam, dirty then clean it. You can try oiling it but if it’s locked up it’s probably toast

 

[johneh]

No Combustion fan No Vav
The Combustion fan draws air through the firebox to give you vac
If air is not being sucked out of firebox the stove will not start. No auger, igniter or convection fan

 

[abcd61]

Thank You. I follow you now. When the stove is turned on, fires up the combustion motor, that creates vacuum which turns on the vacuum switch which starts the other stuff.

I did some more testing and the combustion motor did not run as I thought, Strangely enough the combustion motor light is on at the panel, and it is not seized up, but it is not running.

Another question, the vacuum hose runs from the switch into a hole maybe 4 inches away. About 10 inches of hose gets fed in that hole, but I dont see where it gets connected at that end to anything. I expected it to be connected somewhere.

 

[Overfireinthehole]

It should connect to the vs and the back of the firebox, or on some Harmans vs to the fines box. If you blow through it away from the vs it you should be able to hear if it’s blowing all the way into the front of the stove. What kind of a voltage reading are you getting at the combustion motor?

 

[abcd61]

The voltage reading at the combustion motor looked fine, > 200v I was going to take the motor out and test it, that may take some time one of the mounting screws is frozen in place, all my attempts to remove it ended up stripping the screw head.

 

[Overfireinthehole]

Should be around 120. Usual 118v