Extremely Cold Temperature Furnace Tips

[gahrajmahal]

Below Zero and your furnace stops working?

Before you call your repairman there are a couple of things you can check out. I happened to be home today, enjoying my fireplace and surfing the web when I noticed it seemed to be cold in the room. My furnace is 10+ years old, gas, forced air and is of the newer computer controlled energy saver kind. You know the one with the PVC intake and exhaust outside on the side of the house.

Going upstairs I checked the thermostat first. It was set to 68 F. but registered 61 F. on the digital readout. You know all those digital thermostats use a battery, typically 9 volt, so I will change that in a bit even though the thermostat seems to be working.

Going downstairs I checked to see if the furnace was running and it was not. The first thing I did was to check the ON/OFF switch. Mine was ON, but my son wasted $50 bucks with a service call to our furnace guy Tony. Their ironing board fell against their furnace and bumped the switch to OFF. Tony was pretty good about not razzing him too much. So, check your switch!!

I turned my switch OFF, waited 30 seconds then turned it back ON. My furnace started up but no sound of the spark igniter or the whoosh from the flame starting. Most computer controlled furnaces take a long time to cycle prior to lighting. I pulled off the access panel on the front of the furnace and looked for any obvious reset buttons, but found none. So, approximately 4 minutes later I hear that reassuring whoosh and looking into the viewing window I saw that beautiful blue flame.

If you are reading this and your furnace is working, take some time along with your loved ones to inspect your furnace and identify the OFF / ON switch, how to remove the cover, identify any reset switches and where the viewing window is. It's nicer to do this when it's working.

So, now to get bundled up, go outside and inspect what I believe to be the culprit of my stopped furnace. It is -5 F. outside, so everything is pretty frozen. Turning the corner of the house I immediately find what I expected. One of the pipes for the furnace was frozen and mostly blocked with frost and ice.

The reason I had suspected this is when Tony originally installed this furnace many years ago, he covered the intake PVC pipe with 1/4 galvanized hardware cloth. The wire cloth caught the snow and easily froze over several times. I had replaced the hardware cloth with this stainless floor drain and have never had the problem since. So I guess it has just not gotten cold enough.

I simply popped out the stainless cover and I will replace it once the temperatures go up a bit.

Another addition I have made to my furnace to assure a warm home if the power goes out comes from a Garage Journal post I read concerning a Transfer Switch. I had purchased a Harbor Freight generator during a summer power outage and was wondering if it could power my gas furnace. The post verified that it could but stressed the importance of not feeding power back to your panel by having a transfer switch wired in. This allows you to run a long extension cord (12 ga.) from your generator to the transfer switch. Just flip the switch and your furnace will have 110 volt power to run just like normal but isolates it from the rest of the house. So the rest of the house still won't have any power, but the furnace will run and the pipes wont freeze.

Feel free to add any additional tips to the post. I am not endorsing the transfer switch, it's safety or other liability. I am just informing you all about what may help you keep a warm home during this cold winter.

Edit; Sorry for the BIG photos. I took the pictures on the wrong setting and PhotoBucket did not seem to resize them correctly

 

[Boomer343]

I believe I have the same furnace as you do and in my install manual neither the intake or exhaust should have any restriction. There is a grid insert that goes just before the blower fan on the intake side.
Mine has never frozen up even in minus 40 degrees or had any problems with insects or small animals.
As a suggestion for maintenance, I pull the motor/blower assembly out every few years and clean off the vanes and it runs quieter. Watch for sharp edges.
I also ditched the electronic air cleaner and now use the 4" filters made for the old electronic cabinet.

 

[gungatim]

Here's my tip: keep a spare ignitor or two on hand. you know they are going to burn out, so you're going to need one anyway. waiting on a part to be shipped with no heat is not fun...

 

[David Paul]

Great and timely post. Nice reminder to check the simple things first

 

[Stuart in MN]

I believe I have the same furnace as you do and in my install manual neither the intake or exhaust should have any restriction. There is a grid insert that goes just before the blower fan on the intake side.
Mine has never frozen up even in minus 40 degrees or had any problems with insects or small animals.

When I had my furnace installed I asked the HVAC tech about this as well. I figured it would be a good idea to keep critters out, but he said no screens are recommended. 8 years later and it's still working fine.

 

[mjeff87]

Just went through a 3 week long ordeal with my barely 5 year old Lennox furnace.....I noticed it was not coming on at random times when the tstat called for heat. Checked all the usual suspects, couldn't find anything wrong and just wrote it off as a fluke occurrence (only happened two times over the course of two weeks). Then it started to get more frequent, but thankfully it was still warm outside (40-50 degrees). We have an annual service plan so I put in a service call (no charge). Tech #1 comes out and checks all the same easy stuff as I did and says he can't find anything wrong (problem was very intermittent and I couldn't "force" it to fault, either). Day later, happens again, so same tech comes back out, does some more checking and turns the fan speed up a tad thinking it may be going off on overheat, says call back if that doesn't fix it. It doesn't. Tech #2 now comes out, spends about 3 hours and still can't find anything wrong. Then he says to replace the circuit board as it may be bad......$260 part (not covered under service plan, but I agreed). Swaps board, everything runs great, he leaves. Next day, it craps out again. I install a new tstat on the wall just for giggles, doesn't fix it either. Tech #3 comes out, says he's the tech they send when no one else can figure something out. Nice guy, burned out hippie type, but knows his stuff. Cuts a huge gash in his hand while working on the unit and informs me he's a hemophiliac, and asks me for a bandaid....I gave him half a box. Eventually he diagnoses it as a bad flame sensor, and replaces it (part covered under plan), and I've had heat ever since.

All told, I lost about 2.5 days of work total, but it was worth it now considering it was -1 here last night. I still have the old circuit board (they offered to put it back in and take the new one back for credit), but I figured it would be best to just keep the old one as a (working) backup spare JIC the new one shits the bed at o-dark-thirty some cold winter night.

Jeff

 

[WhoWhatNow]

We had a less that 2 year old furnace stop working one day. It would come on but then shut down almost immediately. Turns out the condensation drain was clogged. If the condensate can't get out the furnace shuts off as a safety.

 

[bw77]

Just went through a 3 week long ordeal with my barely 5 year old Lennox furnace
...
Then he says to replace the circuit board as it may be bad......$260 part (not covered under service plan, but I agreed).

I thought Lennox has a 10 yr parts warranty?
Just for some parts?

 

[bmxdad]

This is a direct vent? I had a direct vent gas furnace installed so I could pull the old chimney down. I'm not to hip on how the exhaust exits the side of the house ... pipe is extended almost a foot away from the outside wall, same with the drain line.

Neither has a cover to keep insects or animals out too.

 

[mjeff87]

I thought Lennox has a 10 yr parts warranty?
Just for some parts?

5 years, not 10......it's about 6 months out of warranty. My service plan ($150/yr) covers "most" parts, but not circuit boards.

 

[info2x]

My uncle fell victim to the switch being flipped at Christmas one year. His switch was at the top of the basement stairs. Someone thought it was a light switch. We bought him a nice red cover...

 

[PelicanPines]

My upstairs furnace is in the attic and has a drain for the high eff heat. Dang thing didn't line up with the outgoing pipe and dripped into the emergency pan... froze... Got a blinking error code. Wouldn't light... Due to a pressure switch error.

Figured I would heat the drain with a hair dryer... had to ALSO heat the tiny vacuum line hoses too, since they froze too.

Perm solution.... lined up drain and insulated the pipes. If this fails, I will add pipe heat tape hooked to a thermostat.

 

[rlitman]

Since the case is part of the seal on a direct vent furnace, if the intake is blocked, opening up the case will allow air from the house in, which will get it started.

But I thought that the down facing pipe should be the intake, and the higher pipe would be the exhaust. It is still possible for an exhaust on a condensing heater to freeze. Actually kind of likely, as condensation can form in the exhaust.

 

[rice rocket]

Previous owners bought a fancy Carrier Infinity furnace that's all electronics and sensor driven, I'm quaking in my boots fearing the day when one sensor fails and I'll be hemorrhaging cash.

 

[Factoryrat]

Flame sensors are cheap too. It doesn't hurt to keep a spare on hand.


Sent from my iPad using Tapatalk

 

[zmaxmotorsports]

Just went through a 3 week long ordeal with my barely 5 year old Lennox furnace.....I noticed it was not coming on at random times when the tstat called for heat. Checked all the usual suspects, couldn't find anything wrong and just wrote it off as a fluke occurrence (only happened two times over the course of two weeks). Then it started to get more frequent, but thankfully it was still warm outside (40-50 degrees). We have an annual service plan so I put in a service call (no charge). Tech #1 comes out and checks all the same easy stuff as I did and says he can't find anything wrong (problem was very intermittent and I couldn't "force" it to fault, either). Day later, happens again, so same tech comes back out, does some more checking and turns the fan speed up a tad thinking it may be going off on overheat, says call back if that doesn't fix it. It doesn't. Tech #2 now comes out, spends about 3 hours and still can't find anything wrong. Then he says to replace the circuit board as it may be bad......$260 part (not covered under service plan, but I agreed). Swaps board, everything runs great, he leaves. Next day, it craps out again. I install a new tstat on the wall just for giggles, doesn't fix it either. Tech #3 comes out, says he's the tech they send when no one else can figure something out. Nice guy, burned out hippie type, but knows his stuff. Cuts a huge gash in his hand while working on the unit and informs me he's a hemophiliac, and asks me for a bandaid....I gave him half a box. Eventually he diagnoses it as a bad flame sensor, and replaces it (part covered under plan), and I've had heat ever since.

All told, I lost about 2.5 days of work total, but it was worth it now considering it was -1 here last night. I still have the old circuit board (they offered to put it back in and take the new one back for credit), but I figured it would be best to just keep the old one as a (working) backup spare JIC the new one shits the bed at o-dark-thirty some cold winter night.

Jeff

Flame sensor is one of the 1st things to check for on a short cycling furnace after the filter.

 

[zmaxmotorsports]

Flame sensors are cheap too. It doesn't hurt to keep a spare on hand.


Sent from my iPad using Tapatalk

They can usually be cleaned rather than replaced.

 

[Factoryrat]

I cleaned mine first with a bounty towel, and a year later it stopped again. I cleaned it again, then ordered one on eBay for $10. Peace of mind.

 

[1950mercury]

Most newer furnaces have error code lights. They are listed on the inside of the door buy the wiring diagrams.

 

[zmaxmotorsports]

I cleaned mine first with a bounty towel, and a year later it stopped again. I cleaned it again, then ordered one on eBay for $10. Peace of mind.

Green scuff pads work good.

 

[plott hound]

funny this thread pops up today when my furnace locked out.woke up this am and it was pretty chilly in here,thought I was gonna have to call my work and get a service guy sent out.turned the thermostat off then back on and the furnace fired back up.i just installed this 2-stage Bryant with a 2-stage stat last summer myself and never expected a hick-up so soon.damn electronic stuff!!!!!!!!!!!

 

[Outlander]

Check your oil tanks!

Recently had the motor on my dual energy go out. It took the circuit board with it (magic smoke). Both covered by my service contract, and the dude came at 11pm to change the motor and give us heat for the evening (emergency mode puts it on oil only). I was impressed.

 

[allinon72]

Mine makes kind of a "rap rap rap" sound when it turns on, like something needs lubed but I have no idea what.

 

[Jackfre]

I clean flame rods with a dollar bill. If it is an expensive house I will use a 20. I used to use sand cloth, but the manuf said scoring the rods actually could increase the build up on the rod, in the right conditions. The buck works well.

 

[Charles (in GA)]

I would think the frozen over vent should be turned down, not the way it is where snow, water, etc can get on it. I recently helped a friend install a 90% condensing gas instant water heater, and the instructions were emphatic that the inlet and outlet both face down, exception was a co-centric exhaust/intake system that could be used. The intake came with a plastic grid with a screen wire covering on it, and the exhaust had a bird stop grate that installed in it similar to the floor drain, except it just shoved into the down turned elbow.

The way the one is turned in the pic seems to be just looking for trouble.

Charles

 

[zmaxmotorsports]

 

[srmofo]

Here's my tip: keep a spare ignitor or two on hand. you know they are going to burn out, so you're going to need one anyway. waiting on a part to be shipped with no heat is not fun...

I had mine burn out a few years ago on a friday night. I made it through the weekend by turning the thermostat up to 90, and then lighting the furnace with a grill lighter snaked into where the igniter is. Once lit I would let it run until it was hot in the house. Once it shut off I killed the switch until it was time to warm the house back up again.

It a giant PITA but I avoided an expensive service call since everyone was closed.

Ive been meaning to order a spare ever since but I still havent done it

 

[Charles (in GA)]

If you replace or re-run either of both of those pipes, 3 inch solid PVC is not found at the box stores. All they will have is cellular core PVC (which you cannot use). I ended up getting a 20 ft stick of SOLID PVC at a supply house. After pricing around, I found a couple of them were crazy high, finally found one that was reasonable. I did find 10 ft sticks at Ferguson but it was 100 miles away and truthfully wasn't saving me much over the 20 ft stick I ended up with.

I would replace both the inlet and outlet. This should be done using the instructions that were provided with the furnace. They will specify the minimum distance from the wall to the inlet and outlet, the minimum distance to the ground, the maximum differential of length between the inlet and exhaust, the max number of elbows allowed in the intake and exhaust, min distance to inside and outside corners, distance horizontally and vertically from openable windows, etc.

Barring having the instructions for this furnace, I would re-run the inlet by turning it down just outside the wall, similar to the current exhaust. The exhaust I would run just like the new intake, straight out from the wall, but extend it at least 12 inches, or up to 18 inches beyond the intake vent, with an elbow on the end. I would then put a screen wire on the intake, and a coarse bird stop on the exhaust.

 

[gahrajmahal]

Thanks to all who have responded. I now have the feeling I should be looking for spares for my furnace, but it is probably old enough now that an exact replacement is not available. I haven't called Tony for several years and wouldn't be surprised if he was retired by now. As for rerouting the inlet/outlet, I have only experienced this during extreme cold temps below zero maybe once or twice before, so I am going to leave well enough alone. Any other tips that may help out our fellow GJ'ers are great. Some pictures of cleaning those flame rods would be appreciated along with how to do it safely would be great.

Stay warm!

 

[brewchief]

Hopefully the pipe that was frozen up was the exhaust, if it was the intake then the terminations are completely wrong.

We find frozen up intakes and exhaust pipes every year when it gets super cold, most are either improper position of the pipes that results in recirculation of the exhaust or somebody has added a metal screen of some type.

I've installed hundreds of furnaces and none of them have come with a screen for either the intake or exhaust, if terminated correctly no screen should be needed. If a critter problem becomes an issue then drill 4 tiny holes in a x pattern and use a piece of monofilament fish line to create a x, it will resist icing up much better.

Other tips,

Filters, change them often if the cheap type, avoid the high dollar 3M filters that are only a inch thick, they load up very quickly and become very restrictive.

Yearly service, a preseason service can reduce the chances of furnace failure during the season. Having a relationship with a good service company can payoff if you have a problem, when it's super cold and calls are stacking up our existing customers get first priority.

Thermostat batterys, change them once a year, on many stats the battery may only be used as backup so the battery may seem to last forever, unfortunately they will corrode and can damage the thermostat if not changed.



For the OP that looks to be a Carrier/Bryant/Payne, many of those have had secondary heat exchanger problems, so many that there is/was a class action lawsuit. Give your guy a call and get it checked out, far easier to plan and schedule time for a repair or replacement then to have it dead in the busiest week of the year.

 

[Br@ndon]

Hopefully the pipe that was frozen up was the exhaust, if it was the intake then the terminations are completely wrong.

We find frozen up intakes and exhaust pipes every year when it gets super cold, most are either improper position of the pipes that results in recirculation of the exhaust or somebody has added a metal screen of some type.

I've installed hundreds of furnaces and none of them have come with a screen for either the intake or exhaust, if terminated correctly no screen should be needed. If a critter problem becomes an issue then drill 4 tiny holes in a x pattern and use a piece of monofilament fish line to create a x, it will resist icing up much better.

Other tips,

Filters, change them often if the cheap type, avoid the high dollar 3M filters that are only a inch thick, they load up very quickly and become very restrictive.

Yearly service, a preseason service can reduce the chances of furnace failure during the season. Having a relationship with a good service company can payoff if you have a problem, when it's super cold and calls are stacking up our existing customers get first priority.

Thermostat batterys, change them once a year, on many stats the battery may only be used as backup so the battery may seem to last forever, unfortunately they will corrode and can damage the thermostat if not changed.



For the OP that looks to be a Carrier/Bryant/Payne, many of those have had secondary heat exchanger problems, so many that there is/was a class action lawsuit. Give your guy a call and get it checked out, far easier to plan and schedule time for a repair or replacement then to have it dead in the busiest week of the year.

What filters do you recommend? I've been using the 3m type. [emoji15]

 

[brewchief]

What filters do you recommend? I've been using the 3m type. [emoji15]

The basic pleated filters that are 3 for 10$ or so are fine

Sent from my SM-G900V using Tapatalk

 

[Stuart in MN]

We had a less that 2 year old furnace stop working one day. It would come on but then shut down almost immediately. Turns out the condensation drain was clogged. If the condensate can't get out the furnace shuts off as a safety.

I don't have a floor drain in my basement, so there's a little condensation pump that sends the condensate water over to the laundry tub. A couple years ago the float switch in the pump failed, so the furnace wouldn't run. I just put the drain line from the furnace in a bucket, and picked up a new pump the next day.

So, the moral of that story is if your furnace won't come on and you have a condensate pump (typically, a Little Giant like this one) check to see if it's working.

 

[Showkey]

If you replace or re-run either of both of those pipes, 3 inch solid PVC is not found at the box stores. All they will have is cellular core PVC (which you cannot use). I ended up getting a 20 ft stick of SOLID PVC at a supply house. After pricing around, I found a couple of them were crazy high, finally found one that was reasonable. I did find 10 ft sticks at Ferguson but it was 100 miles away and truthfully wasn't saving me much over the 20 ft stick I ended up.

Cellular PVC cannot be used....... Maybe not true according to this manaufacturer :

http://securenet.goodmanmfg.com/Too...VC+Cellular+Core+(Foam+Core)+Plastic+Pipe.pdf

We are approving the use of “Schedule 40 PVC Cellular Core (Foam Core) Plastic Pipe” for use as flue/vent pipe material on all 90% plus model gas furnaces installed only in the United States. The “PVC Cellular Core (Foam Core) Plastic Pipe” is manufactured under American Society for Testing and Methods standard ASTM F891.
Schedule 40 PVC Cellular Core (Foam Core) Plastic Pipe is not approved for use in Canada. CSA does not have a Reference Standard for Cellular Core PVC Plastic Pipe.
Schedule 40 PVC Cellular Core (Foam Core) Plastic Pipe is a coextruded poly (vinyl chloride) (PVC) plastic pipe with a cellular core (contains numerous cells intentionally introduced, interconnecting or not, distributed throughout the pipe) and concentric inner and outer solid layers. PVC primer meeting ASTM F656 and PVC solvent cement meeting ASTM D2564 specifications must be used. Fittings must be DWV type fittings meeting ASTM D2665 and ASTM D3311. Carefully follow the manufacturer’s instructions for cutting, cleaning and solvent cementing of PVC.
To ensure proper furnace operation, this Schedule 40 PVC Cellular Core (Foam Core) Plastic Pipe must be installed in accordance with the installation instructions, all local building codes and ordinances. In their absence, follow the latest edition of the National Fuel Gas Code (NFPA 54/ANSI Z223.1), and or CAN/CGA B149 Installation Codes, local plumbing or wastewater codes, and other appliance codes.

Page 15 of these instructions call for PVC or CPVC:

http://www.hotwater.com/lit/im/res_gas/184326-001.pdf

 

[rlitman]

CPVC is CHLORINATED PVC, not cellular. Totally different animal.

 

[Charles (in GA)]

The Noritz water heater instructions I am familiar with are quite emphatic about the use of solid PVC, largely due to temperature limits of the material. The issue I see with Cellular PVC is the exposed cut ends of the pipe at fittings. Hot (well, up to 150°F or so hot) gases bearing on this exposed cell core probably will deteriorate it, where it would not have any affect on the solid PVC material. Solid PVC is easy enough to find, you just gotta go to a supply house. First one I checked wanted $52 for a 20 ft stick. The ten foot stick I found a hundred miles away was $27. I ended up with a 20 ft stick from a supplier about 30 miles away, for $36. I still have 14 foot or so of that stick remaining.

Noritz also cautions about the acidic properties of the condensate. Its not something you want to dump in a septic system, nor have it dump outdoors where it can puddle for animals to consume. If you feel the need for it, neutralizers are available that the condensate can be routed thru.

Noritz NRC 711 installation instructions contain lots of good info on vent pipe routing and locations. The first 18 pages of the manual are devoted to clearances from corners, windows, other vents, etc and the how to and whys of venting the unit. This is a 157K BTU unit, so we are not talking some piddly little amount of exhaust or intake air. Just thought I'd provide the link as a good reference.

Charles

 

[rlitman]

Noritz also cautions about the acidic properties of the condensate. Its not something you want to dump in a septic system, nor have it dump outdoors where it can puddle for animals to consume.

Yeah, but it's easy to deal with. Either run it through a canister full or marble chips, or dump it outside into a pile of marble chips (though dumping outside only works in places that won't freeze).

 

[Charles (in GA)]

This is one commercial alternative I found in a Google search. Looks like you unscrew the ends and replace the stone inside of it (most likely marble or similar).

Rather pricey and you could build one similar with PVC pipe and screw on ends and fittings and ½ vinyl tubing and afore mentioned marble chips.

The condensation that’s produced as a byproduct of burning natural gas or propane is semi-acidic and has the potential to harm sewer systems, your waste water drain pipes, and condensate pumps. Tankless water heaters, boilers, and furnaces that are 93% efficient or higher will produce 1.6 gallon of this acidic condensation for every 400,000 BTUs of natural gas or propane that is burned. The Navien GXXX001322 Condensate Neutralizer Cartridge Kit is designed to neutralize the semi-acidic condensation discharged from your high efficiency gas or propane products ( pH levels of 3-4) by raising the pH of the condensate byproducts to a more neutral level before it is discharged to your drain. Most county building codes require the use of a condensate neutralizer on the drain line of a high efficiency gas or propane product.
Condensate Neutralizer Kit Features:
1.6 Gal/hr for single appliance use only
Prevents acidic condensate from corroding drains and sewer systems
All corrosion resistant materials
Suitable for use on all types of Natural Gas and Propane appliances
Includes initial charge of neutralizing agent
Can be mounted in horizontal or vertical position
Condensate Neutralizer Kit Includes:
One (1) clear corrosion-resistant neutralizer housing with 3" openings (0.26 gallon / 1 liter volume)
1/2" - 14 NPT threaded INLET and OUTLET
Two (2) 1/2" MNPT hose barb fittings
One (1) 1/2" FNPT hose barb fitting
One (1) barbed Y-fitting
One (1) 10' length hose of 1/2" ID vinyl tubing
Six (6) hose clamps
Two (2) base / wall mounting clamps

http://www.the-wholesale-warehouse.net/navien-condensate-neutralizer-cartridge-kit/

 

[gahrajmahal]

Bumping for the season, some great info here...

 

[ForceFed70]

Good info thanks for sharing. Some comments of my own:
1) Showing loved ones where the switch is, I think is a good idea. By pulling the cover to look for reset switches - are you sure? When's the last time you saw a reset switch in a modern furnace? They're all self resetting nowadays and probably best if the family isn't taking the cover off.
2) Insulate that exhaust pipe! 93% efficient still means 7% of the heat is coming out of there and it shouldn't freeze up like that.
3) Consider removing the grate permanently and add another 90* fitting that points down. That exhaust pipe is full of acidic exhaust gas condensate and precipitate. Very rare that you'll have mice or birds, etc crawling in as a result.