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Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 21539
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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I just bought an 8 yr old house with a MG-75N boiler. Its

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I just bought an 8 yr old house with a MG-75N boiler. It's not heating my house. the green boiler light is on, the zone lights are yellow. What should I check/adjust?
Welcome, my name is XXXXX XXXXX I will do my best to help you with your issue.

The first thing to check is the motorized vent damper. Is it open? If it's not open nothing else will happen. If the damper is open check the blocked vent switch. It looks something like this
And it's attached to the open underside of the draft diverter

Push the small button in between the 2 wires to try to reset it. If the button clicks when you push it the burner will start up with any luck. Beyond that there isn't much you can do without troubleshooting with a multi meter. If you have a multi meter let me know have we can try a few other things.

Customer: replied 3 years ago.
That doesn't seem to do anything. I guess I'll need to have someone in to look at it.
Pushing that reset is about all you can do if the damper is open and you don't have a meter. I can help you troubleshoot this further but it sounds like that's not something you want to try. If so your only option is to call in a pro
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