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Would having an open window in a Canadian winter causing the…

Would having an open window...
Would having an open window in a Canadian winter causing the heater to run almost constantly cause a furnace to open the Primary or secondary limit switch?
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Answered in 4 minutes by:
3/8/2018
BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 23,122
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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Hello,

The issue here is the room gets infiltrated with cool air which makes the furnace run longer, but the cool air should also keep the discharge temp under control. Commonly plugged filters, too dense of the newer filters, blocked registers, restricted return air are the things that lead to overheat.

I have not found windows open leading to limit fail but to extended run.

Billy

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Customer reply replied 4 months ago
Ok. The filter isn't very dirty but it is pretty dense. I'll try a less dense one and check the rooms for blocked vents and see if that helps

In order for the limit to be tripped the discharge air from furnace would need to rise. Commonly only air blockages or lack of air can do this.

Many of the newer filters mimic a plugged filter as they are so dense.

Just rate service to move off the active list.

Thank you

BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 23,122
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
Verified
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