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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22541
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I am trying to clear a pressure switch open during run soft

Customer Question

I am trying to clear a pressure switch open during run soft lockout I cleaned all of my condensate tubes and the PT trap I have the furnace running and I'm hoping it stays on but I see no water draining out of the PT trap will it take a while for the condensate water to fill out and a PT trap before it comes out
JA: Did you check the furnace's filters?
Customer: Did you read my whole message
JA: Do you plan on doing the work yourself?
Customer: Yes have you read my message yet
JA: Anything else we should know to help you best?
Customer: Have you read my message
Submitted: 9 months ago.
Category: HVAC
Expert:  BillyHvac replied 9 months ago.


My name is ***** ***** I will do my best to assist you. I am looking over your question now and will respond shortly.

Expert:  BillyHvac replied 9 months ago.

right now it is not draining because the trap is clear....once you shut down or it reaches temp...then the water will drain and fill the trap.

When the trap is empty it sucks air into the pipe...which holds the water until shut down.

Once the trap fills and breaks that air gap it will drain normally. Ask any questions you need to be clear.


Customer: replied 9 months ago.

So why is my furnace tripping off on a soft lockout?

Expert:  BillyHvac replied 9 months ago.

It can be:

obstruction in vent or intake pipe (nest, rodent, leaf).

Secondary exchanger plugged...apply shop vacuum suction direct to furnace drain..

Bad pressure switch, tube or the port the tube attaches to on furnace is partially plugged (poke clear with paperclip)

Customer: replied 9 months ago.

So it triped off and then with me not resetting the furnace it started up again and ran for about 10 minutes. Then stopped. It is still giving me the error code but it is cycling to maintain setpoint. Is this normal?

Expert:  BillyHvac replied 9 months ago.

no it is not normal...once the unit kicks in it should run nonstop to set point instead of cycling to setpoint.

You have a slight blockage or a weak switch..the low switch is famous for getting moisture in it and becoming unreliable.

Customer: replied 9 months ago.

What is the low switch is that the pressure switch?

Expert:  BillyHvac replied 9 months ago.

you have 2 pressures switches

one for low speed heat and one for high speed heat

When I say low switch it is just another way of saying low pressure switch.