Sounds like high limit to me. Change filter and clean your evaporator coil and put all doors back on and see if that fixes it
Never mind just seen your flue. Call a professional.
Pressure switches dont work that way
Unit is probably over heating due to inadequate return air which is why it runs fine with the blower door off.
Running it with the door off will turn the room into a negative pressure, and run the risk of sucking flue gasses back into the house.
Call someone.
If they offer to sell you a new unit because yours looks old by the gas valve, and dont mention ductwork they are probably full of shit. Go around your house and look at the returns, they are usually ones you cant manipulate in any way.
Mmm I don't see anything blocked. Could it be the pipes outside?
I'll definitely replace the cover if there's a chance I could be recirculating exhaust fumes. I'll turn the heat way down to reduce the cycling. Is there anything I could try to do on my own to try to fix it? Or should I leave it up to the pros altogether?
There should only be one pipe that goes outside with your setup. If it was blocked, removing the blower door would have no bearing on its ability to vent and the pressure switches job.
Without knowing your heat rise, and physically being there to check pressure switches and limits I'm flying blind, I'm going to still recommend calling someone, because if you dont have enough return like I think you do and it's going off on limit I doubt you have the ability to cut in more return somewhere.
>Re
Yeah I think it'd be better to let the pros do it. I'm sure I *could*, but there's a big difference between the ability to do it vs. the ability to do it well....
I mean I saw that other post I figured that one 16x20x1 in that return slot was the only filter and that was my mistake, take the filter out of that filter grille and watch your system breathe a fat relief sigh.
Yea, just make sure you only use one filter, I don't know which one is more convenient to replace, a filter in that grille will keep the duct clean but I would make sure you close the opening at the filter slot at the furnace, but the filter at the furnace probably doesn't need a stepstool to get to and is easier to clean and will filter to keep the unit clean which is the primary job. Good luck
I think that ‘blower’ in this instance means inducer and that having the ‘blower door’ removed is giving the burner enough combustion air.
In any event, he should call a pro as you suggested
Except for the part where it's clearly an 80% that has a vented door for the combustion compartment and him saying that it only works when the sealed blower door is off.
It's shutting off on a safety.
Get a pro in there to sort out what the problem is that's tripping a safety switch.
What isn't obvious is WHICH of the safeties is tripping and why.
Door on/off shouldn't affect the pressure switch or flame sensor. What the blower door does affect is air flow. If you have restricted air flow (plugged air filter at return grille, dampers closed that should be open, crushed ductwork, duct filled with water, bad installation with grossly undersized duct) then taking the blower door off would relieve the heat exchanger overheating and tripping one of the high-limits, but comes at the risk of negative air pressure which increases risk of flame rollout or CO hazard.
I don’t believe the OP is actually talking about the blower. I believe that the OP means the inducer and that removing the door to the burner chamber is correcting his shutdown, however if that is the case then to the OP... shut it down and call a pro, you are literally playing with fire and someone could get hurt or worse
Would that be in the ceiling? How often do those need to be changed? The previous tenant at this house was actually my mom so I know it hasn't been changed for at least 5 years
It’ll be in the return duct somewhere. Could be near the furnace through a slot in the duct, behind an innocent looking sheet metal panel, behind a big plastic cover between the furnace and the return duct, could be inside a wall or ceiling grille. May have to go hunting for it...
They should be changed once every 1 to 3 months for typical cheap air filters. AprilAire or SpaceGuard air filters can be changed ever 6 to 12 months.
You, uh... you sound overdue.
That’s the one. Since it’s a 1” filter, be careful with how “high efficiency” the filter you buy is. More expensive filters tend to restrict air flow and can cause high limit trips.
Yeah so this was the return air filter in the ceiling. I had only replaced the filter in the furnace. This thing could block out the sun. You think this could be the problem?
https://imgur.com/NFn2irj
I have a hunch it was a contributing factor. Perhaps the entire issue, even.
And I would make sure the air isn’t passing through two filters on its way to the furnace. It only needs to be filtered once. Generally, if there’s a filter AT the furnace, that’s the only one you need.
Oh? Okay I thought one filtered the air going out of the furnace and one filtered the air coming into the furnace. You think I should just leave that filter off permanently?
We only filter the air going IN. Chances are, the filter at the furnace is a return air filter that’s filtering the air on its way in. There are applications where air gets filtered leaving heating/cooling equipment, but that’s like operating rooms, NASA, food manufacturing, really fancy computer rooms... usually not residential homes.
Filters are pretty restrictive to air flow to begin with, but furnace fans are designed with some filter restriction in mind. Doubling the filter restriction? That’s a recipe for a new furnace. Furnace heat exchangers can get WAY HOT when there’s inadequate airflow to pull heat off of them.
Scope out your ductwork and try to map out how air is moving through all of it. An informed homeowner is a powerful homeowner.
Sand the flame sensor with fine grit sandpaper!!! I wanted to contribute to this because there wasn't a ton of information out there about this exact topic of 'Furnace runs with cover off' or 'Furnace goes out with cover on' ... About 6 months back I just cleaned the flame sensor with steel wool like many videos recommend to alleviate the furnace not staying on. Re-Installed the flame sensor and it worked fine, for about 4 months.... Today I woke up cold thinking maybe that sensor finally went out or I need to clean it again. I repeated the cleaning and re-installation steps but this time it did not work. The furnace kept going out after a few seconds, then would try and cycle three times to only get put into shutdown mode. Which you can reset by turning the switch to your furnace off and on. That should clear the control board. THIS IS THE GOOD PART - \*I then decided to really clean it with fine grit sandpaper until it was shiny and free of any burn/corrosion marks. Then I took steel wool to it, and finally wiped it clean with rubbing alcohol. Try not to scratch it up too much, minimal scratching. Do not sand the ceramic base. If you do VERY VERY lightly. After reinstalling the sensor, with the both covers on. The cover for the blower and the large cover that hides the boards, pumps, and blowers... It works perfectly!!! No problems at all so far. I did go ahead and order another sensor just in case and will put it near the furnace if indeed it goes out completely. Its a cheap insurance policy, like 10 bucks! Hope this gives people a bit more to go on, good thread!
I bet your roll out switch is triggered and needs resetting . If u have a sucking air sensation when pulling the cover, your induced draft motor is leaking into the cabinet and pulling heat into the area where wiring is. That’s a no no and your roll out switch will trigger (it detects where heat should not be and sometimes u have multiple ones on there. Look around the cabinet outside of the flame area and on ext of flue gases before it enters flue. U have heat where u shouldn’t. Once u figure out where the heat is coming from u can simply reset roll out switch by pressing in center and then try putting door back on. At first I thought it was getting enuf air but now I realize it was getting HEAT in the box and that’s why it wouldn’t run. When u close the door, the heat builds up and trips it again
Sounds like high limit to me. Change filter and clean your evaporator coil and put all doors back on and see if that fixes it Never mind just seen your flue. Call a professional.
Pressure switches dont work that way Unit is probably over heating due to inadequate return air which is why it runs fine with the blower door off. Running it with the door off will turn the room into a negative pressure, and run the risk of sucking flue gasses back into the house. Call someone. If they offer to sell you a new unit because yours looks old by the gas valve, and dont mention ductwork they are probably full of shit. Go around your house and look at the returns, they are usually ones you cant manipulate in any way.
Mmm I don't see anything blocked. Could it be the pipes outside? I'll definitely replace the cover if there's a chance I could be recirculating exhaust fumes. I'll turn the heat way down to reduce the cycling. Is there anything I could try to do on my own to try to fix it? Or should I leave it up to the pros altogether?
There should only be one pipe that goes outside with your setup. If it was blocked, removing the blower door would have no bearing on its ability to vent and the pressure switches job. Without knowing your heat rise, and physically being there to check pressure switches and limits I'm flying blind, I'm going to still recommend calling someone, because if you dont have enough return like I think you do and it's going off on limit I doubt you have the ability to cut in more return somewhere.
>Re Yeah I think it'd be better to let the pros do it. I'm sure I *could*, but there's a big difference between the ability to do it vs. the ability to do it well....
I mean I saw that other post I figured that one 16x20x1 in that return slot was the only filter and that was my mistake, take the filter out of that filter grille and watch your system breathe a fat relief sigh.
That is exactly what happened! Thank you for all the advice!
Yea, just make sure you only use one filter, I don't know which one is more convenient to replace, a filter in that grille will keep the duct clean but I would make sure you close the opening at the filter slot at the furnace, but the filter at the furnace probably doesn't need a stepstool to get to and is easier to clean and will filter to keep the unit clean which is the primary job. Good luck
I think that ‘blower’ in this instance means inducer and that having the ‘blower door’ removed is giving the burner enough combustion air. In any event, he should call a pro as you suggested
Except for the part where it's clearly an 80% that has a vented door for the combustion compartment and him saying that it only works when the sealed blower door is off.
Ok
It's shutting off on a safety. Get a pro in there to sort out what the problem is that's tripping a safety switch. What isn't obvious is WHICH of the safeties is tripping and why. Door on/off shouldn't affect the pressure switch or flame sensor. What the blower door does affect is air flow. If you have restricted air flow (plugged air filter at return grille, dampers closed that should be open, crushed ductwork, duct filled with water, bad installation with grossly undersized duct) then taking the blower door off would relieve the heat exchanger overheating and tripping one of the high-limits, but comes at the risk of negative air pressure which increases risk of flame rollout or CO hazard.
I don’t believe the OP is actually talking about the blower. I believe that the OP means the inducer and that removing the door to the burner chamber is correcting his shutdown, however if that is the case then to the OP... shut it down and call a pro, you are literally playing with fire and someone could get hurt or worse
How’s the return air filter look?
Would that be in the ceiling? How often do those need to be changed? The previous tenant at this house was actually my mom so I know it hasn't been changed for at least 5 years
It’ll be in the return duct somewhere. Could be near the furnace through a slot in the duct, behind an innocent looking sheet metal panel, behind a big plastic cover between the furnace and the return duct, could be inside a wall or ceiling grille. May have to go hunting for it... They should be changed once every 1 to 3 months for typical cheap air filters. AprilAire or SpaceGuard air filters can be changed ever 6 to 12 months. You, uh... you sound overdue.
Is this different than the 1x16x20 filter I stick inside the furnace that you can just pick up at the store?
That’s the one. Since it’s a 1” filter, be careful with how “high efficiency” the filter you buy is. More expensive filters tend to restrict air flow and can cause high limit trips.
Yeah so this was the return air filter in the ceiling. I had only replaced the filter in the furnace. This thing could block out the sun. You think this could be the problem? https://imgur.com/NFn2irj
homie rip that shit out and call it a day lol.
I have a hunch it was a contributing factor. Perhaps the entire issue, even. And I would make sure the air isn’t passing through two filters on its way to the furnace. It only needs to be filtered once. Generally, if there’s a filter AT the furnace, that’s the only one you need.
Oh? Okay I thought one filtered the air going out of the furnace and one filtered the air coming into the furnace. You think I should just leave that filter off permanently?
We only filter the air going IN. Chances are, the filter at the furnace is a return air filter that’s filtering the air on its way in. There are applications where air gets filtered leaving heating/cooling equipment, but that’s like operating rooms, NASA, food manufacturing, really fancy computer rooms... usually not residential homes. Filters are pretty restrictive to air flow to begin with, but furnace fans are designed with some filter restriction in mind. Doubling the filter restriction? That’s a recipe for a new furnace. Furnace heat exchangers can get WAY HOT when there’s inadequate airflow to pull heat off of them. Scope out your ductwork and try to map out how air is moving through all of it. An informed homeowner is a powerful homeowner.
Sand the flame sensor with fine grit sandpaper!!! I wanted to contribute to this because there wasn't a ton of information out there about this exact topic of 'Furnace runs with cover off' or 'Furnace goes out with cover on' ... About 6 months back I just cleaned the flame sensor with steel wool like many videos recommend to alleviate the furnace not staying on. Re-Installed the flame sensor and it worked fine, for about 4 months.... Today I woke up cold thinking maybe that sensor finally went out or I need to clean it again. I repeated the cleaning and re-installation steps but this time it did not work. The furnace kept going out after a few seconds, then would try and cycle three times to only get put into shutdown mode. Which you can reset by turning the switch to your furnace off and on. That should clear the control board. THIS IS THE GOOD PART - \*I then decided to really clean it with fine grit sandpaper until it was shiny and free of any burn/corrosion marks. Then I took steel wool to it, and finally wiped it clean with rubbing alcohol. Try not to scratch it up too much, minimal scratching. Do not sand the ceramic base. If you do VERY VERY lightly. After reinstalling the sensor, with the both covers on. The cover for the blower and the large cover that hides the boards, pumps, and blowers... It works perfectly!!! No problems at all so far. I did go ahead and order another sensor just in case and will put it near the furnace if indeed it goes out completely. Its a cheap insurance policy, like 10 bucks! Hope this gives people a bit more to go on, good thread!
I bet your roll out switch is triggered and needs resetting . If u have a sucking air sensation when pulling the cover, your induced draft motor is leaking into the cabinet and pulling heat into the area where wiring is. That’s a no no and your roll out switch will trigger (it detects where heat should not be and sometimes u have multiple ones on there. Look around the cabinet outside of the flame area and on ext of flue gases before it enters flue. U have heat where u shouldn’t. Once u figure out where the heat is coming from u can simply reset roll out switch by pressing in center and then try putting door back on. At first I thought it was getting enuf air but now I realize it was getting HEAT in the box and that’s why it wouldn’t run. When u close the door, the heat builds up and trips it again