Heating & Cooling Logo

Related Topics:

Posted on Apr 03, 2009
Answered by a Fixya Expert

Trustworthy Expert Solutions

At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.

View Our Top Experts

Pressure, draft safeguard, or aux limit swtch did not close or re

I have a carrier furnace. Pressure, draft safeguard, or aux limit switch did not close or reopened. This is what my furnace is blinking as a LED code. What should I do? My furnace does not turn on.

1 Answer

Donni Steen

Level 3:

An expert who has achieved level 3 by getting 1000 points

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

Vice President:

An expert whose answer got voted for 100 times.

  • Master 687 Answers
  • Posted on Apr 03, 2009
Donni Steen
Master
Level 3:

An expert who has achieved level 3 by getting 1000 points

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

Vice President:

An expert whose answer got voted for 100 times.

Joined: Jan 05, 2009
Answers
687
Questions
0
Helped
446491
Points
2142

The limit switches are two wires that go to a small disk about the size of a dime. There should be a tiny button between the wires. Find all the limits and push them to reset them. The draft safeguard is the one that is located where the flu pipe leaves the unit. Sometimes the limits are stubborn and it's hard to push them in. If you can't get it reset then the limit will need to be replaced but it can be bypassed temporarily by jumping the two wire together. Do no do this as a permanent fix. It can cause death.

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1helpful
1answer

Carrier infinity furnace 2010 has stuck inducer pressure switch, Can I manually bypass and heat the house until serviceman arrives tomorrow?

I wouldn't bypass any safeties when its part of the exhaust system of the furnace. That is the first safety that acts in the furnaces sequence of operation. The induced draft will initiate and that pressure switch will close, proving the IDM is working and flue is clear. It's primary purpose is to exhaust any fuel that may linger inside the heat exchanger and then to reject the post combustion process. Carbon monoxide becomes an issue. As far as the Infinity, these units will not start if safeties are bypassed. The unit checks all safeties/circuits for continuity, and if a switch is closed when its not supposed to be, it won't allow.
tip

Heater check out list for heater failures

Almost all furnaces built after 1978 have intermittant type pilots.
Ca banned them requiring electronic spark or hot surface ignitors, followed by induced draft motors, pressure switches or centrifigal switches that "prove" a induced draft exists, allowing the pilot sequence to commence.
electronic spark type units have a high voltage low amperage spark that is AC. Fire rectifies electricity that passes through it meaning AC becomes DC ! Fire is a terrible conducter however as a result , the DC signal is only milliamps/volts signal strength. the DC prescence is proof a flame exists for pilot, and safe to commence to mainburners.

As long as pressure switches stay closed, safeties and limits stay closed
and the DC signal to the ignition module is not broken, the furnace will run.

The normal sequence of operation is upon a call for heat from the thermostat a 24 volt signal is sent to W white (heat circuit) at the low voltage terminal board on furnace.
from there depending on unit and age the heat circuit may include a circuit board, but it still has the typical limits and safetys reqired for operation
its just not using electromechanical relays to control fan and induced draft motor etc.

for the induced draft to begin ,all limits, safetys in heat circuit must be closed.

induced draft begins and a proving switch, either pressure or centrifigal close allowung the pilot to begin, a spark or hot surface ignitor is energized and a pilot flame established,modern types use flame rectification to prove a flame, older Carrier, Payne,types have a 3 wire switch in the piloyt assembly that is a bi metal that expands and contracts clicking open and shut, allowing pilot or main burners, depending if cold or hot.

pressure switches are attached with tubing to the induced draft wheel housing and sense pressure differential and close upon induced draft running, the orifices that the tube attaches to on induced draft housing often plugs or is restricted causing pressure switch to fail to close, or waver on open and close , open , close, .

if you can run the fan in the on postion , you have both high and low voltage to the furnace.

if you dont have fan control check power, breaker , fuses.
on Dec 04, 2009 • Heating & Cooling
0helpful
1answer

Furnace will not light

If the inducer runs for a short time and shuts off and the main blower comes on and runs it could be a high limit switch or a roll out switch.it could also be a pressure switch that is stuck in the closed position. Most new furnaces have to read the pressure switch in the open position and then the closed position after the inducer fan starts. . Hope this helps.
0helpful
1answer

Furnace gas valve is not opening

YOUR FURNACE IS IN LOCKOUT MODE DUE TO A SAFETY FEATURE OF UNIT. USUALLY THE HIGH LIMIT HAS BEEN TRIPPED, OR YOU PRESSURE SWITCH FROM DRAFT INDUCER MOTOR FAULTY OR PLUGGED. IT WILL CONTINUE LOCKOUT MODE UNTIL THIS IS FIXED.
0helpful
2answers

Why does the led on my furnace control bd flash three times

Hello, this indicates a open limit switch. A limit l switch will open when the temp in the heat exchanger gets too high and this switch shuts the Furnace down for safety. Usuaully a dirty filter, weak blower motor, dirty blower wheel will cause a limit switch to open.
0helpful
2answers

Goodman 95 %furnace keeps saying low pressure is stuck. changed out low pressure switch and high pressure switch and still have same problem.

That thang might be sensing a lazy flame. In other words the flames took too long in the board's opinion to quit sensing the flame. Yall probably need to do pressure tap on the gas valve.
Here is a realistic look at goodman fault codes and what to check fer and I am assuming you are not a tech and don't know this already and am hoping it helps:


Read one LED flash that stays on continuously to mean your furnace has no signal coming from the thermostat and will not operate. Turn the power off and check the thermostat for improper settings or connections.

Interpret one LED flash that blinks on and off to mean your furnace has locked out because it could not ignite after three tries, and must be reset. Interrupt power to your furnace for 20 seconds or lower the thermostat so your furnace does not try to heat, then reset the thermostat to the previous setting. After one hour of lockout, your furnace will automatically reset itself and try to operate as usual.

Decipher two LED flashes to mean the draft blower is not working, or your furnace has a short in the pressure switch circuit. Turn off the furnace power and repair a short or replace the pressure switch.


Read three LED flashes to mean your furnace has an open pressure switch circuit or it has an induced draft blower operating. Check the pressure switch hose of your furnace for blocks or an improper connection. Also, look for blockages in the flue, and tighten any loose wiring.

Translate four LED flashes to mean your furnace has a primary limit circuit open, possibly from loose wiring or blocked filters. Check and clean filters, tighten wiring and check the flue for blockages.

Interpret five LED flashes to mean your furnace senses a flame without a call for heat. This could be from a gas valve closing slowly or a burner flame lingering.



Read seven LED flashes as a warning of a low flame sense microamp signal. This could happen with a coated flame sensor or a lazy flame from poor gas pressure. Turn off the power and adjust the gas pressure according to the information on the rating plate.



See eight LED flashes as meaning an igniter circuit problem due to a bad igniter or an igniter connected improperly. Replace the bad igniter or check the ground wiring, making necessary corrections.



Decipher nine LED flashes to mean the high-stage pressure switch circuit will not close during a high-stage-induced draft blower operation. Your furnace may have a pinched or blocked pressure switch hose, a blocked flue or loose wiring.

Read continuous flashing on the LED to mean your furnace has a reversed polarity of 115 volts. Turn off the power and correct the wiring polarity after reviewing the wiring diagram.

Now here is how it should all go down:



Bottom dollar: it all goes back to type of gas, the initial setup, the pressure tap. and how it is wired up to begin with.
This will give you an idea where to start I hope.

If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61

0helpful
1answer

I AM WORKING ON A CARRIER 90% FURNACE. IT WILL NOT FIRE UP. IT SHOWS A 34 CODE. THE IGNITOR DOES NOT ENERGIZE FROM THE BOARD. NO POWER COMING FROM THE BOARD. I HERE A CLICK AS IF IT IS TRYING BUT NO...

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad ignitor what I see most of the time is the following sequence of operation:


1. Thermostat calls for heat.

2. Draft inducer motor starts.

3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes.

4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. 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 shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas. Solution: You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks. Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. Please see "limits, rollout switches & furnace control boards" further down on this page. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

0helpful
1answer

Carrier 58sxc120 won't ignite and I get a fault code blinking light of short long short don't know what it means.

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad ignitor what I see most of the time is the following sequence of operation:


1. Thermostat calls for heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. 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 shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas. Solution: You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks. Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. Please see "limits, rollout switches & furnace control boards" further down on this page. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

1helpful
1answer

York "high Aux or spill limit switch open"

how can I fix the spill limit switch, also how do I found it
2helpful
3answers

Pressure, draft safeguard, or aux limit swtch did not close or re

The limit switch on the inducer has tripped. There are two wires that go to a small disk about the size of dime that has a small button in the center. Push this little button and you will feel a littl snap and the unit should fire up. Check all the manual reset limits as well. If the unit still won't start, jump the two wires by bypassing the limit switch. If it starts, then replace the switch. Bypassing the switch is only temporary and could lead to death if it is used as a permenant fix.
Not finding what you are looking for?

425 views

Ask a Question

Usually answered in minutes!

Top Carrier Heating & Cooling Experts

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6988 Answers

Jay Finke
Jay Finke

Level 3 Expert

1397 Answers

Mike Cairns
Mike Cairns

Level 3 Expert

3054 Answers

Are you a Carrier Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...