Jump to content
Click here to check out this guide.

FAQs | Repair Videos | Academy | Newsletter | Contact


DISCLOSURE: We may earn a commission when you use one of our coupons/links to make a purchase.
  • Upcoming Events

    • 30 March 2024 02:00 PM Until 03:00 PM
      0  
      All Appliantology tech members are invited to join in this workshop on all things Appliantological: bidness, customers, tools, troubleshooting, flavorite brewski, whatever. Webcams and microphones are open and live!
      This workshop is also a great time for any students at Master Samurai Tech to bring any and all questions about the coursework. We're happy to walk through any concepts you're having trouble with. Think of it like office hours with your teachers. 
      If you have a specific appliance problem you'd like us to talk about, post it here! We need a problem statement and a PDF of the tech sheet or schematic so we can all see it on screen share. If you have a PDF that isn't already in the File library here at Appliantology, send it to us by attaching it to the contact form. 
      Also, follow this Calendar Event so you'll get notified of new posts here. Look for the "Follow" button either at the top of the topic on desktop or below the topic on mobile.
      Who: This workshop is only available to tech members at Appliantology.
      When: Saturday, March 30 @10:00 AM Eastern Time.
      Where: Online via Zoom
      How:
      Click here to go to the forum topic with the registration link. If you're interested, register now. Arrive a couple minutes early to make sure your connection is working. Set a reminder for yourself for this workshop so you don’t miss it.  And check out past workshops here: https://appliantology.org/announcement/33-webinar-recordings-index-page/

RHEEM gas furnace pressure switch wont work


ws105261

Recommended Posts

My RHEEM horizontal gas furnace will not heat. When thermostat calls for heat, the exhaust blower comes on but nothing else happens. I had service tech to check it out. He said I needed a new pressure switch, the one that sends signal to the igniter. I replaced pressure switch (P1 on schematic) with a new one, but get the same results. There is not enough vacuum from the exhaust blower to activate the pressure switch. I have disconnected the flue from blower so I know flue obstruction is not the problem. I can manually operate the pressure switch and furnace operates as it should. Any thoughts on how to increase vacuum?

Model #

RGJA-10ETAGS

Serial #

CF5D307D50932537

Thanks

Link to comment
Share on other sites

  • Replies 2
  • Created
  • Last Reply

Top Posters In This Topic

  • applianceman18007260692

    1

  • Bobice

    1

  • ws105261

    1

Popular Days

Top Posters In This Topic

Problem: Furnace ignitor will not glow. If a furnace has a bad ignitor, open limit switch, open rollout switch, open pressure switch or bad control board. This is what I see in the furnace sequence of operation:

1. Thermostat calls for heat. You should be getting 24 to 28 volts AC between the W (white) and C (com) terminals on your control board. *Make sure furnace safety switch is pressed in when testing.

2. Draft inducer motor starts. If draft inducer does not start then you either have a thermostat problem, thermostat wiring problem, transformer problem, bad relay on control board or a draft inducer problem.

3. Pressure switch attached by a small plastic or rubber tube to the draft inducer senses the negative pressure produced by the draft inducer and closes. Should have 24 volts to ground across both terminals on the pressure switch. If pressure switch is not closed with draft inducer running check for stopped up vent or stopped up drain line on a condensing furnace.

4. Limit Switch and rollout switch/switches should all be closed. Press in on the reset button in the center of each rollout switch to make sure each rollout has been reset. You should have 24 to 28 volts from each terminal to ground. On most furnaces the ignitor will not glow unless all the safety controls (limit, rollout switch/switches, pressure switch) are closed. If a limit or rollout switch is open then you might have an over heating problem and a possible dangerous condition. If the Limit or rollout continues to trip I would strongly recommend calling an HVAC service company to check your furnace out.

5. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. If you hear a hissing gas sound then more than likely either the ignitor is broken or the relay on the control board that sends power to the ignitor is broken. If the ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace will shut down, and try ignition again. Most of the time after three tries the furnace will and go into a lock out condition until you turn your power switch back off and on again.

Solution: You might need a new ignitor, rollout switch, limit switch, pressure switch or control board

Link to comment
Share on other sites

Change the hose between the inducer motor and the pressure switch.

The switch works on suction so if it has a hole in it or is restricted or has a loose connection then the suction will be lost.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...