quadrafire mt Vernon vacuum switch error (Even when switch bypassed)

[Peter Martin]

Hello. I have a 10 year old Mt Vernon that always gives me some issues when I start up for the first time in the fall. This year is no exception. I'm getting the vacuum sw error notification on the control panel, even with the vacuum switch bypassed. What would be the next troubleshooting step in this case? Do I have to replace the harness that attaches to the vacuum switch, or is there a way to test the harness first? When I get the vacuum sw error is it possible that the feeder motor is not responding? Is there anything that I can test on the board itself?

Sorry for all the questions, but it's going to be getting cold soon.

Pete

 

[johneh]

Does the exhaust blower(fan) come on at the start?
Check snap disc #2 it is in the same circuit

 

[Peter Martin]

Hi. I played around with the harness and got the switch to close once it was jumped. There must have been a loose connection at the control board. So, that problem is solved. However, I'm still getting a vacuum switch error when I don't bypass the vacuum switch. The stove is very clean out through the exhaust fan, but I did notice a draft right where the vent pipe attaches to the exhaust fan. This must be causing the stove not to be able to generate a vacuum? If that is true, can someone explain why a leak in the vent pipe would cause a vacuum problem? The vent pipe ultimately opens to outside the house, and a vent pipe leak just causes that opening to happen earlier. I realize that it's very, very bad to have a leak into the house, but I'm curious as to the physics of what is happening, because it doesn't make intuitive sense.

I'm getting the leak plugged now, but would love to hear an explanation of the whole vacuum process.

 

[johneh]

Only if there is a vac leak before the fan eg Door Gasket and the like
or if the exhaust path is plugged will you not get vac.
Take the hose off the vac switch and plow into it (toward stove )
make sure it is clear. If it is your most likely cause of the switch not working is
the switch needs replacement. To measure the vac you would need a manometer

 

[joescho]

My understanding of it (and please correct me if its wrong) is the whole vacuum premise is to get any smoke generated in the pot to go up your chimney. The exhaust fan is in the chamber between the pot and the connection to the chimney vent. It starts and creates a vacuum through the chamber and up the chimney. As johneh said, the door gasket or a bad fit with your ash pan will cause it to suck air too much air and cause a crappy vacuum thus the error.

(I think) LOL

Having said all that, kap is pretty darn knowledgeable about all of this and has helped me quite a bit in the past.

 

[johneh]

The vac switch is a safety switch that tells the stove that it has a draft
and will not burn back into the pellet feed hole so it is ok to feed pellets
The draft is to feed the fire with air for a clean and efficient burn
Then again I don't design or build them just fix them to keep me busy in my retirement

 

[Peter Martin]

That's super helpful, guys. I think I get it now.