HVAC Help: Furnace Issues?

[dj_rice]

Not sure if theres anything wrong with my furnace just yet.

Its a mid-effiencency Lennox furnace. House built in 2000. Furnace duct and furnace checked was just cleaned in Oct 2013.

Woke up this morning, and it was 16C in the house. Thermostat is set on 18-19 all day. Furnace was on, just blowing cold air.

Went down to furnace, switched the main switch to off. And then turned it back on. Turned thermostat to 20C. Went down to check and watched the furnace fire up and flame up and function like normal. So far its working normal from the 20 mins I checked before I went to work.

From searching Beyond, found a couple old threads saying it could be the flame sensor?


Thanks in advance

[95EG6P]

im in the same boat i just got my new house this weekend and the main floor blows hot air but the upstairs blows arm cool air so i am freezing upstairs :cry:

[gyromonkey]

I have fixed many many furnaces over the years working for builders and on the Mid efficient ones the Flame sensor is typically the main issue , Some time the Relay/Transistor that converts the 24v low voltage from the thermostat to 110V and call for heat dies but when that happens the furnace stops working completely. you Can clean the flame sensor and it may work for 5 year but I recommend that your pick up a spare so when its -35 and it happens again your not trying to track one down.

I Have a fancy sales trailer in Cochrane where my current project is and I replaced the flames sensor (30 bucks and the Relay and it was 25 bucks), Most places carry them you just need your make and model, Take a photo of your serial number and that way they have all the info they would need, sometimes it saves a trip lol

Ryan

[gyromonkey]

Originally posted by 95EG6P
im in the same boat i just got my new house this weekend and the main floor blows hot air but the upstairs blows arm cool air so i am freezing upstairs :cry:

Check on your main plenum and see if your furnace is set up for a zone system, If it is make sure both zones are open, I've seen people spend thousands on insulation and repairs and in the end it was just the zone was shut off, Typically its just a little lever

[95EG6P]

Originally posted by gyromonkey


Check on your main plenum and see if your furnace is set up for a zone system, If it is make sure both zones are open, I've seen people spend thousands on insulation and repairs and in the end it was just the zone was shut off, Typically its just a little lever

may be a stupid question but where is the main plenum it is my first place so i am fairly new to everything

[95EG6P]

Originally posted by gyromonkey


Check on your main plenum and see if your furnace is set up for a zone system, If it is make sure both zones are open, I've seen people spend thousands on insulation and repairs and in the end it was just the zone was shut off, Typically its just a little lever
also how can i tell if i am set up for a zone system thanks for all the info i appreciate it

[gyromonkey]

Originally posted by 95EG6P


may be a stupid question but where is the main plenum it is my first place so i am fairly new to everything

The main plenum is attached to the furnace its the large rectangle metal box, the bottom will be attached to the furnace and the furnace filter will be between the two. at the top of the plenum it will branch off into heat runs, some of the runs will be for the basement, some for the main floor and some for the upper, if you follow the runs you will be able to see which ones are for what floors unless your basement is developed, In that case you may just have to feel them. On the runs that do go upstairs look for leavers and see if they are closed, Depending on when and what heating company did your install theirs leavers or thier could be a white box with low voltage run to it and it would be electrically controlled, newer houses over 2399 sqft have a zone system or 2 furnaces . If that does not work you may have to balance the rest of the house and by doing that it forces the air upstairs.


Hopefully that helps, If your still having issues shoot me a PM and we can work it out over the phone

[dj_rice]

Would there be blinking lights on the furnace somewhere that would indicate what the issue would be?

[95EG6P]

Originally posted by gyromonkey


The main plenum is attached to the furnace its the large rectangle metal box, the bottom will be attached to the furnace and the furnace filter will be between the two. at the top of the plenum it will branch off into heat runs, some of the runs will be for the basement, some for the main floor and some for the upper, if you follow the runs you will be able to see which ones are for what floors unless your basement is developed, In that case you may just have to feel them. On the runs that do go upstairs look for leavers and see if they are closed, Depending on when and what heating company did your install theirs leavers or thier could be a white box with low voltage run to it and it would be electrically controlled, newer houses over 2399 sqft have a zone system or 2 furnaces . If that does not work you may have to balance the rest of the house and by doing that it forces the air upstairs.

ok thanks i will try all this stuff when i am done from work thanks again i apprciate it


Hopefully that helps, If your still having issues shoot me a PM and we can work it out over the phone :thumbsup:

[95EG6P]

^^ i will try all those things when i am done work thanks again

[OU812]

also see if your air intake is blocked outside

[gyromonkey]

Originally posted by dj_rice
Would there be blinking lights on the furnace somewhere that would indicate what the issue would be?

It depends on the make and model, Typically theirs a green and red LED that will display codes, the legend should be on the removable door on the inside or out side.

[Zero102]

Sometimes opening the door resets the blink codes so look through the window before opening the door to get a better view of the circuit board. On my furnace there is the outer cover which you remove to see the igniter and flames and such, then an inner cover to access the main board. The inner cover has a window on it, but the LED is a good 6" away from the window and you have to jam your face on the basement floor to see the LED, but there is a switch on the inner door and as soon as you open it the power is cut and the blink codes are reset.

[dj_rice]

Originally posted by Zero102
Sometimes opening the door resets the blink codes so look through the window before opening the door to get a better view of the circuit board. On my furnace there is the outer cover which you remove to see the igniter and flames and such, then an inner cover to access the main board. The inner cover has a window on it, but the LED is a good 6" away from the window and you have to jam your face on the basement floor to see the LED, but there is a switch on the inner door and as soon as you open it the power is cut and the blink codes are reset.



Awesome!!! Thanks for the tips and thanks gyromnkey. Much appreciated!

[gyromonkey]

Originally posted by dj_rice




Awesome!!! Thanks for the tips and thanks gyromnkey. Much appreciated!


No prob man, Let me know if you run into anything else

[dj_rice]

Originally posted by gyromonkey



No prob man, Let me know if you run into anything else


Just checked the furnace for the diagnostic lights. Both were flashing and from the Youtube video I watched, it said it is a failure with the ignition and that the furnace went into lockout mode and to reset it, just turn off the power, which I did in the morning.


Its functioning normal now so I will keep watching. Will attempt to clean the flame sensor tomorrow and buy a spare as well.

[95EG6P]

Originally posted by gyromonkey
I have fixed many many furnaces over the years working for builders and on the Mid efficient ones the Flame sensor is typically the main issue , Some time the Relay/Transistor that converts the 24v low voltage from the thermostat to 110V and call for heat dies but when that happens the furnace stops working completely. you Can clean the flame sensor and it may work for 5 year but I recommend that your pick up a spare so when its -35 and it happens again your not trying to track one down.

I Have a fancy sales trailer in Cochrane where my current project is and I replaced the flames sensor (30 bucks and the Relay and it was 25 bucks), Most places carry them you just need your make and model, Take a photo of your serial number and that way they have all the info they would need, sometimes it saves a trip lol

Ryan

hi i just called my builder supervisor and they said the reason my bedroom is cold is cause the furnace is the furthest from the room and said it will take longer to heat up as the other rooms and downstairs will heat fast then my master, also said to turn off some vents in the basment and some in the other rooms so the heat will reach my master faster. Is he feeding me BS or is that normal thanks for all the imput and i dont think my furnace has any flames that i can see

[RX_EVOLV]

my furnace crapped out on me last night again :-/ same problem with no flame and alternating lights. Tried cleaning the sensor with a steel wool and on luck so I'm going to see if I can buy a new flame sensor locally and swap that... if not then it's time to call someone to come check it out.

[gyromonkey]

Originally posted by 95EG6P


hi i just called my builder supervisor and they said the reason my bedroom is cold is cause the furnace is the furthest from the room and said it will take longer to heat up as the other rooms and downstairs will heat fast then my master, also said to turn off some vents in the basment and some in the other rooms so the heat will reach my master faster. Is he feeding me BS or is that normal thanks for all the imput and i dont think my furnace has any flames that i can see

is your master above the Garage? if so do you know if they spray foamed the floor?

What hes has told you to do is balance the house, It's pretty typical sadly the longer the run the less heat you get. Its sort of like plumbing the farther the fixture is away from the main the longer it takes for get hot water and has less pressure. theirs ways to fix this like a dual zone system, I'm assuming if your builder is telling you to balance the house theirs no dual zone, so like he said try closing some of the registers on the main floor, the closer to the furnace the better, If your not noticing any change you can get tin tape and tape the basement heat runs that way you loose less heat down in the basement, Its not code to tape joints in residential HVAC but some builders do like mine did. I would not close your all your basement ones, maybe one or two their should be 4 down there so close one or two and see if that helps worst case you can use insulation in the runs to block the heat and force it to the second floor.

Just don't let anything freeze!!

[Maxt]

Originally posted by RX_EVOLV
my furnace crapped out on me last night again :-/ same problem with no flame and alternating lights. Tried cleaning the sensor with a steel wool and on luck so I'm going to see if I can buy a new flame sensor locally and swap that... if not then it's time to call someone to come check it out.
Do you have a volt meter that measures micro amps?

[Maxt]

Originally posted by gyromonkey
I have fixed many many furnaces over the years working for builders and on the Mid efficient ones the Flame sensor is typically the main issue , Some time the Relay/Transistor that converts the 24v low voltage from the thermostat to 110V and call for heat dies but when that happens the furnace stops working completely.
Ryan
Not trying to pick on you, but proper terminology goes a long way and the 110v is converted to 24v for the control circuit.
http://en.wikipedia.org/wiki/Transformer

[gyromonkey]

Originally posted by Maxt

Not trying to pick on you, but proper terminology goes a long way and the 110v is converted to 24v for the control circuit.
http://en.wikipedia.org/wiki/Transformer

Honestly man I typed the reply from my cell during my busy day and I wrote Transistor instead of transformer my bad, that was like ten posts ago, don't you have anything else better to do. I'm just trying to help a guy out so he does not pay hundreds of dollars to get a guy out on new years eve.

[Unknown303]

Originally posted by Maxt

Not trying to pick on you, but proper terminology goes a long way and the 110v is converted to 24v for the control circuit.
http://en.wikipedia.org/wiki/Transformer

Not trying to pick on you either but he was definitely talking about the relay triggered from the 24v circuit that turns on the 110v equipment in the furnace. Although in my furnace the 24v circuit goes to an input in the flame controller. so really the micro controller in my furnace is the "relay" driving all the 110v equipment.

[Maxt]

That reply made no sense to anyone who can or would try to read the schematic in their own furnace, if the info is wrong, what help is it?

[Unknown303]

Can I retract this statement? :whipped:...

Edit: Ha and I just found a 24v/110v wiring diagram for a thermostat..

[Maxt]

Where exactly do you think the 24 volts comes from to drive the fancy relay you speak of .... The fancy transformer I speak of.

[Unknown303]

I'm sure glad you haven't been quoting me. You're definitely right on that. I wasn't even thinking about that side of the control circuit for some reason.

[Maxt]

ha. no worries..

[gyromonkey]

So with all this stuff being said, Do we know if the OP and the other guy got things sorted out?

[Unknown303]

I was actually thinking about dj_rice's issue and reminded me of earlier in the winter my boys rooms was getting really cold at night. I was getting ready to troubleshoot and sort out what needed to be replaced etc, ended up checking the filter first and it was fairly dirty, after replacing it I was getting heat throughout the house like normal again.

[gyromonkey]

Originally posted by Unknown303
I was actually thinking about dj_rice's issue and reminded me of earlier in the winter my boys rooms was getting really cold at night. I was getting ready to troubleshoot and sort out what needed to be replaced etc, ended up checking the filter first and it was fairly dirty, after replacing it I was getting heat throughout the house like normal again.


Actually that's a really good call, Sometimes its a really simple solution. I know most builders recommend you replace your furnace filter every month for the first year because of all the dust from construction in the community. Good call

[Maxt]

Also people tend to go with the allergen pleated filters thinking its best for their house. Those filters are so good and restrictive, that some furnaces don't have enough blower to suck through them, or they get dirty within a week and shut the furnace down. Especially systems designed around a 16x25x1 small farm animal stopper.
GyroMonkey is right about the flame sensors on mid efficients going bad a lot, since the combustion air is mixed with air within the building, fouling was a real common problem.
The high efficiencies with dedicated combustion air piped directly to the combustion chamber has really cut down on that problem. I have yet to replace a flame sensor on a high efficiency come to think about it, lots of hot surface ignitors, but no flame sensors.

[dj_rice]

Originally posted by gyromonkey
So with all this stuff being said, Do we know if the OP and the other guy got things sorted out?


For me, yes its all fixed. I haven't pin pointed what caused it YET but I just turned my furnace off and back on and it seems to be working normal again.

Although, initially on the day it stopped working, I did replace the filter on first instinct since its been 4-5 months since it was replaced so don't know if that had anything to do with it working again. The filter that was in it was pretty clean though so...

[Unknown303]

If mine goes 3 months they are done for. Over the winter I'm probably going to keep changing them every month or two at least. Huge improvement going to a new filter in my place.

[redmethods]

A little off topic, but seeing that we are taking Furnaces.
I wanted to ask you guys about filters and air cleaners. I have a Trane Furnace & I'm running a 5" air filter.
My question is, what to you think of the CleanEffects
AIR CLEANER? You don't have to buy any more filters. The 5" air filter are pretty pricey & I was wondering if this would save me some money in the long run.

http://www.trane.com/residential/products/air-cleaners/cleaneffects-air-cleaners

[Zero102]

Originally posted by dj_rice



Just checked the furnace for the diagnostic lights. Both were flashing and from the Youtube video I watched, it said it is a failure with the ignition and that the furnace went into lockout mode and to reset it, just turn off the power, which I did in the morning.


Its functioning normal now so I will keep watching. Will attempt to clean the flame sensor tomorrow and buy a spare as well.

There should be blink codes written on the inside of the cover - don't trust youtube videos.

That said, it is probably ignition lockout just like you suspect but it's worth checking that the blink codes on your furnace are indeed the same. The most common cause of ignition lockout is a dirty flame sensor. Usually it will clear after some time on it's own, though on some furnaces it does require a power cycle to reset the ignition lockout.