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Vent or inducer motor runs all the time

Usually when the Vent or Inducer motor runs all the time
The pressure switch is usually bad
The furnace board is seeing that the pressure switch is open, so it brings the vent blower on to close the pressure switch but the switch being bad won’t close so the furnace board will keep the inducer motor running continuously.

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changed inducer motor, now furnace will not ignite and gives code 31


since there is no model number to go by, let's go generic. Most inducer motors have some way of "proving" it is running to the control board. It may have a centrifugal switch in it or it may have use some type of air pressure switch. The centrifugal switch will usually have 2 wires other than the power wires and most of the time, go to the rear of the motor. The air switch usually has a small rubber hose that pushes onto it and is connected to the fan housing.

Aug 06, 2017 | Carrier Heating & Cooling

1 Answer

My RUUD furnace, model ugld-06nc-er the fan won't turn off.


If the blower motor runs continousley and the thermostat is not set to fan then the intergrated control board is malfunctioning and must be replaced. Usually because the relay that energized the motor is bad. If you are refering to the inducer motor running all the time then the pressure switch is open and must checked for a restriction in the flue pipe or blockage in the vent.

Jan 17, 2011 | Heating & Cooling

1 Answer

intertherm gas furnace inducer centrifugal switch does not close in time. Blower works but furnace does not ignite


Chances are the draft inducer motor is not pulling enough CFM through the heat exchanger.

That is usually due to either blocked/clogged flue pipe/vent.
damaged, missing or dirty fan blades.
or a motor going bad.

Check those three things first, as they are the usually problem. Other than that, it would be a sticking or bad switch.

If you s-uck on the end of the hose like a straw, while it is attached to the switch and it does not pull in then you are looking at a bad switch/cracked hose issue. If it does, then you are back to the draft inducer motor or it's squirrel cage fan being bad.

These are notorious for rusting and the blades breaking off.

Oct 03, 2009 | Heating & Cooling

1 Answer

heat not coming on carrier gas pack code 31


code 31 indicates pressure switch did not close or reopened during the heat cycle....1st thing to check is the inducer motor,,this is a small motor that turns a small blower wheel that draws the exhaust gases through the furnace and blows them into the vent pipe....1st locate the inducer assembly,,most easily identified by the small plastic fan blade that cools the inducer motor as it runs..1st turn off tstat and turn off furnace power switch..then turn on furnace switch,then set tstat to heat,set the temp above room temp by 5 degrees...remove the furnace front cover,locate the inducer motor,,if it isnt turning,but is warm or hot after a minute or so,likely the inducer motor is bad..if it isnt turning and isnt warm after 1 minute,then likely the main control board is bad,,not turning the inducer motor when it should,,,,,if the inducer motor is running,,then the pressure switch isnt closing,, could be a bad pressure switch but more likely there is a problem with the venting...some possible problems that would cause the pressure switch not to close in an 80% eff furnace [metal vent pipe] are: [1] a blockage in the vent pipe,base of chimney,dead bird at the furnace where vent connects to furnace or down inside the inducer assy,accessed by removing vent pipe from furnace....if all clear the chimney could be blocked up inside,,is the draft good when vent is removed from base of chimney?..if furnace is a 90%+ type [pvc plastic vent pipe],,then check the intake pipe at the furnace by removing it where it attaches to top of furnace..is the intake clogged with anything?..then check the intake and exhaust pipes outside for blockages,,including ice/frost/snow at the exhaust pipe outlet..

Jan 26, 2009 | Goodman GMS90703BXA Heater

2 Answers

Janitrol/Goodman GMP075-3 Draft Inducer Fan Won't come on


most forced draft fans are powered by 120 volts . close to the fan is usually a plug that unsnaps. create a call for heat after turning off to clear safetys and see if your getting 120 to fan on initial call for heat. if you are then fan draft motor is bad, usually sold as an entire assembly replace exact as it came out. sequence of operation is..... stat calls for heat via common and white wire to furnace , 24 volts. ......board sences call and sends 120 volts to forced draft ........ motor runs and creates pressure on proofing switch,....... switch closes 24 to board and tells it draft fan is on......... board then energizes ignitor,....... after ignitior glows gas valve is opened and burner lights ........ either ignitor or seperate sensor rod tells board the burner lit........ and a few minutes later the fan comes on and hot air is blown out. if a step is missed or doesn't proof the furnace either trys up to three times to light or locks out. turning off power usually resets safetys and it will resume attempts to lite normally.

Oct 25, 2008 | Heating & Cooling

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