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Gaztech, HVAC Technician
Category: HVAC
Satisfied Customers: 485
Experience:  Owner at Gaztech
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I have a lennox ml 193 uh furnace. Everything appears to be

Customer Question

i have a lennox ml 193 uh furnace. Everything appears to be working except the furnace is blowing cold air. I am not getting any heat/flame in the furnace. The LED light is showing Red = off and Green = slow flash.
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Yes i checked the thermostat and changed the filter
JA: Do you plan on doing the work yourself?
Customer: If it is an easy fix then i will do it myself
JA: Anything else we should know to help you best?
Customer: no i think thats it. i am wondering if its an ignitor switch
Submitted: 11 months ago.
Category: HVAC
Expert:  Gaztech replied 11 months ago.

Welcome to Just Answer, my name is Luke

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Expert:  Gaztech replied 11 months ago.


− Check that the pressure switch is open without the combustion air inducer operating.

Means that the pressure switch is stuck, it is the round black puck shape device that has small tubing to it coming from the power ventor. blow air back in forth in the puck to unstuck it, but you will probably need to replace it as it will happen again.

Replace if defective.