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BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22515
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I have a Carrier 58RAV down flow/horizontal furnace. The

Customer Question

Customer: I have a Carrier 58RAV down flow/horizontal furnace. The limit switch keeps tripping after every heat cycle (heat comes on, reaches temperature, then turns off and doesn't come on again at next call for heat). Looking at the diagram in the manual, it looks like it's the "draft safeguard tube and switch" that keeps turning off rather than the manual reset limit switches, and pushing it back in again resolves the issue. I follow the manual furnace shut down/start up procedure each time. It's a pain in the butt, as it's cold here and it's taking a lot of time just to keep my family warm!At the same time, our thermostat (the only one in our home) is malfunctioning. I've replaced the batteries, so I feel I can eliminate that variable. It seems to have a mind of it's own; I set the temperature to 70 for example, I *think* it reaches it, then I go to check the thermostat for verification and it shows 65, while the house temperature is registering at 61. I reduce the temperature to below 61 to bring back higher to initiate the call for heat sequence, only to have it start up and get error code 13 on the furnace. I'd like to know if the thermostat malfunctioning is the reason the furnace keeps turning off with error code 13, or is the furnace the reason the thermostat isn't working properly? Also, could it be as simple as me not replacing the furnace door properly and it's getting a draft of air from where it's not secure? The access door doesn't seat properly in the bottom left corner. I tried using electrical tape to hold it in place and it didn't resolve the issue.I hope everything I've said makes sense! Please let me know if there are any points of clarification. Long story short: I'm getting error code 13 on the furnace after one cycle of heat. Thermostat is all over the place. Please let me know what I should be looking for/doing to fix it!
JA: Thanks. Can you give me any more details about your issue?
Customer: I have a Carrier 58RAV down flow/horizontal furnace. The limit switch keeps tripping after every heat cycle (heat comes on, reaches temperature, then turns off and doesn't come on again at next call for heat). Looking at the diagram in the manual, it looks like it's the "draft safeguard tube and switch" that keeps turning off rather than the manual reset limit switches, and pushing it back in again resolves the issue. I follow the manual furnace shut down/start up procedure each time. It's a pain in the butt, as it's cold here and it's taking a lot of time just to keep my family warm!At the same time, our thermostat (the only one in our home) is malfunctioning. I've replaced the batteries, so I feel I can eliminate that variable. It seems to have a mind of it's own; I set the temperature to 70 for example, I *think* it reaches it, then I go to check the thermostat for verification and it shows 65, while the house temperature is registering at 61. I reduce the temperature to below 61 to bring back higher to initiate the call for heat sequence, only to have it start up and get error code 13 on the furnace. I'd like to know if the thermostat malfunctioning is the reason the furnace keeps turning off with error code 13, or is the furnace the reason the thermostat isn't working properly? Also, could it be as simple as me not replacing the furnace door properly and it's getting a draft of air from where it's not secure? The access door doesn't seat properly in the bottom left corner. I tried using electrical tape to hold it in place and it didn't resolve the issue.I hope everything I've said makes sense! Please let me know if there are any points of clarification. Long story short: I'm getting error code 13 on the furnace after one cycle of heat. Thermostat is all over the place. Please let me know what I should be looking for/doing to fix it!
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to HVAC Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: how long is a bit?
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.

hello,

are you sure it is the draft safety button you keep resetting?

Billy

Customer: replied 1 year ago.
do you have access to the manual for this make/model of furnace? in the diagram, it shows #9 draft safeguard tube and switch....that's what i've been pushing to reset it each time
Expert:  BillyHvac replied 1 year ago.

Thank you,

yes I have all the documentation. Have you removed the vent pipe to look for blockage, animal nest etc?....

Customer: replied 1 year ago.
not yet....i banged on it with a screwdriver and some sandy material fell out from where the straight ducting met the elbow
Customer: replied 1 year ago.
is that where i should start first?
Expert:  BillyHvac replied 1 year ago.

When this switch trips...it is always a blockage in chimney or vent. It will keep tripping until the blockage is gone. The thermostat is erratic because everytime this trips, the furnace cuts power to the thermostat

Customer: replied 1 year ago.
any tips for anything that'll help loosen the screws holding the ducting together? my drill ain't cutting it...
Expert:  BillyHvac replied 1 year ago.

it is usually 1/4" sheet metal screws. 1/4" socket or 1/4" bit in a drillworks well

Customer: replied 1 year ago.
ok. what about wd-40...is that safe given the heat exposure? (heat's off until this is fixed though)
Expert:  BillyHvac replied 1 year ago.

wd wont help much in this case. Plus once project is done you would likely get some odor and smoke..

When all else fails just a basic 1/4" nut driver works.

Customer: replied 1 year ago.
ok, i got screws out of the elbow part, top and bottom. can't quite maneuver it out. the part above it is where the ducting from the water heater meets the ducting from the furnace in a "y" and i'm afraid to mess with what isn't broken in regards ***** ***** water heater ducting.
Customer: replied 1 year ago.
should i just mess with the elbow some more until i can get it out on it's own?
Customer: replied 1 year ago.
should i try to send you a pic of what i'm talking about?
Expert:  BillyHvac replied 1 year ago.

There are a couple ways.

You can try the elbow or drop a chain down chimney.

Remove directly at chimney.

The end result is there is something in the vent pipe or chimney

Customer: replied 1 year ago.
can't drop a chain down the chimney til tomorrow....too dark out to get on the roof. want to resolve this tonight if possible since it's so cold. would like to fix it at elbow if possible
Expert:  BillyHvac replied 1 year ago.

you can also remove the water heater all in one piece. Instead of taking it apart...you can lift off

water heater and leave a few pieces together

Customer: replied 1 year ago.
was able to get the elbow off and used a broom handle to poke up as far as i could go....didn't feel any obstructions and there wasn't as much sandy stuff as i thought there would be...there was some but not much
Customer: replied 1 year ago.
also just looked up through the whole ducting to the chimney with a flashlight and didn't see any kind of obstructions
Expert:  BillyHvac replied 1 year ago.

what about back into the furnace

Customer: replied 1 year ago.
awaiting your response before putting ducting back together
Customer: replied 1 year ago.
nope, nothing down there either...poked and looked with flashlight.
Expert:  BillyHvac replied 1 year ago.

start briefly with pipe off just to see if fan throws anything out

Customer: replied 1 year ago.
is that safe? should i just follow the basic furnace start up procedure?
Expert:  BillyHvac replied 1 year ago.

we are not starting burner...we just want the exhaust fan to run a few seconds with pipe off and then turn off

Customer: replied 1 year ago.
i should turn on the gas control knob, turn the gas back on, then turn on the furnace breaker in that order?
Customer: replied 1 year ago.
then off in that reverse order?
Expert:  BillyHvac replied 1 year ago.

leave gas knob off

leave gas valve off

just turn on breaker

then thermostat

as soon as the fan attached to the vent pipe runs a couple seconds...turn off.

Then put pipe back together

then gas knob on

gas valve on

breaker on

thermostat to heat

Customer: replied 1 year ago.
ok, fyi the air coming out of the open ducting didn't feel very forceful...should it?
Expert:  BillyHvac replied 1 year ago.

that depends on blower speed and if filter is clean...

Is the unit running a cycle right now?

Expert:  BillyHvac replied 1 year ago.

.

Customer: replied 1 year ago.
nope, i just had the breaker on and turned the thermostat to fan rather than auto so that the heat wouldn't come on
Customer: replied 1 year ago.
just put ducting back together
Customer: replied 1 year ago.
i checked the filters yesterday and they are super clean
Customer: replied 1 year ago.
going to try to heat now
Expert:  BillyHvac replied 1 year ago.

thank you

Customer: replied 1 year ago.
turned on heat to 70, says it's 60 in the house now
Customer: replied 1 year ago.
i'll keep you posted as to what happens
Expert:  BillyHvac replied 1 year ago.

just respond as you can

Billy

Customer: replied 1 year ago.
it just reached 70, and though the house temp reads 70 while it shows 63 on the right where there should be a 70 as well (the left side number shows the house temp., the right side number shows the temp. i'd like the temp to be). i checked to see if there would be an error code blinking on the furnace as there usually is when this happens, but the light is staying steady.
Customer: replied 1 year ago.
i'm hoping that it's been resolved, as there not being a 13 error code gives me hope. i'll keep ya posted.
Expert:  BillyHvac replied 1 year ago.

so what is the update today on the furnace?

Customer: replied 1 year ago.
well, it seemed to be working fine all night with multiple heat cycles. this morning when we got up the heat setting was at 67, as i had set it before bed, and the house temp. read 63. i reduced the heat setting to below 63 to initiate the call for heat cycle and went to the furnace to see what happened. the furnace started but got error code 13 again but rather than stay blinking at 13 it went back to a steady red light. this is different than before i cleaned the ducting...it would just blink a steady 13 continuously then.
Customer: replied 1 year ago.
i pushed in the draft safeguard switch again and turned the thermostat up and the heat came on, which it is now...
Expert:  BillyHvac replied 1 year ago.

ok if it recovered on its own...without pressing a button...it is an over heat temp inside furnace and not the vent trip.

From the blower motor are wires that attach to the circuit board...can you tell me which wire of those is attached to a terminal labeled HEAT

Customer: replied 1 year ago.
i've attached pix of the blower motor and the circuit board....if you could guide me as to what wire to look for it would be very helpful, as the circuit board of wires is kind of overwhelming! don't know where to even start looking for words on terminals except for the 'test' one.
Expert:  BillyHvac replied 1 year ago.

ok bottom right hand corner.

you will see a block of 4 wires...black yellow blue and red.

The black is on top of a blue....just switch the black and blue...

Thaat way the blue is on top and black on bottom

Customer: replied 1 year ago.
all done. what did that do?
Expert:  BillyHvac replied 1 year ago.

that raised the blower speed. This should run more air through furnace and lower the temp.

Now you can try for a day or 2 and see if the limit trip (13) stops

Customer: replied 1 year ago.
great! so it's safe to start up again now?
Expert:  BillyHvac replied 1 year ago.

correct...all set

Customer: replied 1 year ago.
just now getting to turn on the heat, and it just went straight to error code 13
Customer: replied 1 year ago.
the heat didn't come on at all
Customer: replied 1 year ago.
my bad, didn't turn the gas back on
Customer: replied 1 year ago.
ok, update: turned the heat back on, came on for a bit, then shut off with error code 13 after about 5 minutes and well before reaching set temperature. the fan is still running in the furnace, but the blower has shut off. what next?
Customer: replied 1 year ago.
the fan just shut off. error code 13 blinking continuously now. one long, three short
Expert:  BillyHvac replied 1 year ago.

ok the code is not 13....it is 31.....verify by counting the short blinks first and then long

31 is an entirely different situation

Customer: replied 1 year ago.
i apologize, there was nothing in the manual that explained how to read the error codes. my bad....what's the course of action now? should i switch back the black and blue wires on the circuit board?
Expert:  BillyHvac replied 1 year ago.

no problem...now we need to key in on the exhaust fan....

is it running consistently? Does this motor ever not start or stop during a cycle? Is 31 ever present when exhaust is NOT running?

Customer: replied 1 year ago.
the exhaust fan is what pumps the heat into the house? it only comes on during the heat cycle; not running consistently.
Customer: replied 1 year ago.
i mean constantly, not consistently. if i turn on the fan rather than auto switch on the thermostat, then it runs constantly
Customer: replied 1 year ago.
is the exhaust fan what's called the blower motor in the manual?
Expert:  BillyHvac replied 1 year ago.

the exhaust fan is what blows air out of the vent pipe/chimney

Customer: replied 1 year ago.
how would i test that?
Customer: replied 1 year ago.
should i switch the wires back on the circuit board before troubleshooting anything else?
Expert:  BillyHvac replied 1 year ago.

switch the black and blue back where they were.

You would need to remove the exhaust motor to see if all the fins are in place and no feathers in blower wheel. Can you take the exhaust fan off the front wall?

Customer: replied 1 year ago.
wires are switched back. here's a pic of what i'm seeing....can you please use it to explain where the exhaust fan/front wall are?
Customer: replied 1 year ago.
i can reach around the side where the circuit board is and feel the inside of the blower, but can't see inside of it
Expert:  BillyHvac replied 1 year ago.

I will need pic from bottom section

Customer: replied 1 year ago.
k, i'll go take that now. i reached my phone around the side of the blower and was able to take this pic. be right back with the bottom section pic
Customer: replied 1 year ago.
here's the bottom furnace. what i've been pushing in to get it working again each time is at the top right, in between the two red wires
Expert:  BillyHvac replied 1 year ago.

the black plastic wheel is attached to the back of the exhaust fan

Customer: replied 1 year ago.
ok, so what should i do with it?
Expert:  BillyHvac replied 1 year ago.

the round metal plate will come off ...there are only 4-5 screws and that whole motor and wheel pull straight out...we need to see inside that

Customer: replied 1 year ago.
that round plate is all i need to take off, not the black wheel and all the housing in front of it?
Customer: replied 1 year ago.
will it be easy enough for me to put back after checking it without messing it up?
Expert:  BillyHvac replied 1 year ago.

all of that comes out in one piece. Once you remove the few screws that mount the assembly the whole thing slides out.

As far as installation it just slides back in place....all depends on your comfort level.

Customer: replied 1 year ago.
from sewing machine repair i know that some motors have "timing" that's really hard to dial back in without being a professional....does this have that?
Expert:  BillyHvac replied 1 year ago.

no this is simply a free rotating fan with no sequence to match

Customer: replied 1 year ago.
ok.
Customer: replied 1 year ago.
i checked it out and there seem to be 3 screws holding it in. i feel i've reached the point of what i can do on my own, as the video link you sent is WAAAAAAY over my head. is there any other possible way to troubleshoot this issue from my limited experience without tinkering in the exhaust fan?
Expert:  BillyHvac replied 1 year ago.

how do you feel about just removing those 3 screws and sliding it out....looking...and sliding back in with 3 same screws?,,,,nothing else?

Customer: replied 1 year ago.
i'm not sure i have the proper tools, as 2 of the screws are recessed behind the triangular plate and i don't have the proper drill bit to get them out. i want to be sure that i can at least have the furnace working as much as it had been and am worried that if i don't put it back properly i won't even be able to do that.
Expert:  BillyHvac replied 1 year ago.

I understand. I am afraid this is the last point. The code and operation all center on this fan or something inside the fan.

You will need to call for service to go any further.

Customer: replied 1 year ago.
ok, thank you SO MUCH for all of your help! it's been so frustrating not being able to figure this out on my own. i'm used to being able to fix things! and it's important for my family to be warm AND save $ on having someone come out. i really, really, REALLY appreciate all your guidance and expertise. in the off chance i can get the right drill bit, is there a way i can contact you directly to go through the process of removing the fan?
Expert:  BillyHvac replied 1 year ago.

all you need to do is respond to this same thread in your account. Plus after the service is rated I am available for 30 days of free followup

Customer: replied 1 year ago.
ok billy, i've got a theory here....bear with me:i've been observing the thermostat..it's been driving me nuts. it has been running fine at night and most of the issues i've told you about occur during the day. i was able to dig up the thermostat manual and this kind of thermostat has to be programmed with a heating AND cooling program. i was confused when i didn't hear the click on the thermostat for heat until it got over 67, even though it should have come on at a lower temp. according to the house temp. reading. when i checked the 'view program' button, it showed 67 as the programmed temp. i think the furnace was tripping when i was trying to get heat during the pre-programmed cooling cycle. you think that could be it?
Customer: replied 1 year ago.
at this time of year, i don't want any kind of cooling program, and don't understand how/why to program it in addition to a heat program. i just want the house to be a certain temperature, and when it dips below that temperature, for the heat to come on....
Customer: replied 1 year ago.
it also just seems to be not registering the proper temps....it's reading 63 for house temp when it's definitely warmer than that while the heat temp says 72...it shut off at 63. this does not happen at night.
Customer: replied 1 year ago.
it was a corroded battery terminal on the thermostat the whole time!

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