Boiler reliability in -45 degree weather

subaru400

I haven't had a problem (yet), but a lot of people are worrying me that I'll have a failure over the next couple days due to abnormally low temps. Anything from freezing condensation at the top of my stack, to freezing returns. My steam system has been fine so far, but are there any issues that I might anticipate and/or precautions I can take to lessen my paranoia?

Fred

I assume this boiler and the wet returns are in the basement, right? It's not going to get much below 50 degrees down there and the boiler will be running long enough and often enough that nothing is going to get cold enough to freeze, including the return water. The steam mains will be hot and they don't hold much water and what little condensation is in there won't freeze. Same is true for the stack, it will be hot!
If the boiler fails and you can't get a Pro out in a reasonable time, drain the boiler and if you can drain the wet returns and the water heater. Turn the water supply to the house off at the water main, open all the faucets in the house and find a location at the lowest point of the house (maybe the water heater drain) to drain the water pipes. All will be well.

Mike

Set your thermostat to your normal setting, maybe a little warmer. And leave it there. No set back. Let the system work. Might not shut off, but let it run and maintain temp.

subaru400

Yes, it's all in the basement. I'm assuming all that draining would be to prevent bursting pipes in the event of a freeze, since my household water source (including the water heater) splits off from the feeder valve source at the main. Thank you for the peace of mind, Fred and stay warm.

Jamie Hall

Steam is much more forgiving that way -- with very very rare exceptions there is nothing to freeze except in the basement -- which, believe me, will be nice and toasty. The only time I've ever had a problem, and it was an exceptional situation, is I once had a radiator trap freeze. Quickly fixed with a heat gun.

Fred

Yes, all the draining is only in the event your boiler were to fail and you can't get a heating Pro out the same day. You will be fine. We are expecting wind chills at -35 here too and it will only last a couple days. I'm not going to spend a single minute worrying about anything I can't control but I will be ready to spring into action if need be. You stay warm as well!

mikeg2015

Let’s see...

I’m a service tech. For condensing furnaces, we keep ferncos and sawzall ready for this weather.

No PVC pipe to plug up with ice.
No PVC intake to plug up with snow.
No pressure switches
No inducers
No blower fan
No tube heat exchangers to crack
No dirty air filter or undersized ductwork to cause hi limits to trip

Control boards are really simple and a generic Honeywell replaced about 99% of boiler control boards. Could make it work in a pinch with just a couple relays.

IF power goes out, you need about 20-40 watts to run it at most. Could use a inverter hooked to a car battery if needed.

mikeg2015

2 condensing furnaces today with frozen condensate traps. One in a drafty basement, the other improperly placed in a uninsulated attic.

The other a failed inducer and HSI in a Mobil home.

All units were about 8-10 years old. All looked ready to be thrown out a replaced.

Fixed a boiler last week that had been literally under water at one point. Rusty and looked bad, but works great. Just needed a new control board. Probably 25 years old. Good for another 20 I’d guess. They never have to add water I’m told.

EBEBRATT-Ed

@subaru400

You will probably have fewer problems with it running in cold weather