Have HVAC Questions? Ask an HVAC Expert for Answers
Hello and thanks for using this service, if you have been waiting do not worry or get upset I am just one of the techs on here and I try to get to as many customers as I can and I just picked up your question now. Please give me time to respond sometimes I get your replies late so there may be a delay in my response.
Can you check if the ignitor has power to it when the unit comes on and the exhaust fan starts up?
That is a pressure switch fault, is the exhaust fan running and is the rubber tube and port clear from the inducer housing to the pressure switch. The port where the rubber tube connects often gets blocked or the exhaust port itself could be blocked, check that.
Find the rubber pressure tube on the exhaust blower housing and pull it off and see if the port is clear.
Ok check the exhaust port outside to make sure it is clear and you can feel air moving out when the exhaust fan is on.
You can or just go outside and check the pipe at the outlet.
If it is blowing air then the pressure tube port should have a slight vacuum on it. If so you likely have a bad pressure switch on the unit that is where the tube connects to on the other end. If so you can try to bypass it to see if it works by connecting the 2 wires to the pressure switch together when the fan comes on for a call for heat If it starts up and lights then replace the pressure switch.
We are on the honor system for our time, all I ask is please rate my service using the STAR RATING LINK on your page before you leave. If you are not happy with the service please let me know before leaving a negative rating. This is the only way I am paid or credited through the site for my time. This will also allow you to get directly back to me for FREE follow up questions and tips are greatly appreciated! Thanks
The Low fire one
You have to do it in order (sequence), wait until the fan comes on and then put them together.
Just replace the low fire one.