Quadrafire Classic Bay 1200 Circuit/Switch Testing

[utbiochemist]

I have a classic bay 1200 that is not feeding pellets. The exhaust fan starts and the call for heat light is on when I raise the thermostat. I have replaced the vacuum switch and the auger motor, checked the vacuum hoses, and checked the stove door gasket - all seem to be fine. The control box isn't doing anything weird - one orange blink followed by several single blue blinks. The unit will light if I manually add pellets to the pot. I bought a multimeter and am hoping someone can tell me what settings to test each switch on, and what the readings should be across all three snap discs as well as the pressure switch. Right now, I am getting a reading of 0.9v going into and out of the vacuum switch, 120v in and 0 out on Snap disk 1 or 2 and 0.3V in and out on the other snap disc (I can't remember which is which right now. Snap disc 3 is giving me fluctuating in and out on both sides - sometimes at 120v. sometimes 90v, sometimes almost nothing, with no apparent reason for it. I've ordered a control box and hopefully replacing that today since there doesn't seem to be power to the vacuum switch and since Snap disc 3 power is inconsistent.

I have two concerns - 1. the unit was running fine until it was cleaned professionally, and then it wouldn't properly start up again, making me wonder if something shorted out my control board and 2. I don't know what the readings SHOULD be a both sides of all switches/discs so that I can diagnose the thing next time BEFORE I go replacing every single part. Can someone Describe in detail what the readings should be? This single mom with a cold house sure would appreciate it!

 

[Ssyko]

Snap disc’s are spring steel thermostats some are closed on the rise of temperatures,(low limit). some are open on rise of temperatures, (high limit). They will be like a light switch, On or off. Best way to test one is to take it out of the circuit, make a jumper wire that will connect to the wires that are on the disc. Place your jumper in place of the switch. Bookmark this website there is vast knowledge in these threads.

 

[kappel15]

And when jumping wires together, make sure not to ground them out on the stove. And always unplug the stove before removing or installing a control box, or you run the risk of toasting it. Try to download a manual for your stove if you don't have one. And the #1 snap disc runs the convection fan only, and has power to it all the time so be careful. #2 snap disc shuts power off to the auger if the stove gets too hot. And #3 snap disc shuts power off to whole stove if a fire up drop tube is sensed. Did you try cleaning out the nipple on the drop tube that the vac hose attaches to? Best test for vac issues which can be a number of things is to jump the vac switch wires together,making sure you don't ground them on the stove. I made jumper wires with spade connectors on them for easy testing and less chance of grounding out. kap