Gas furnace question

[Chalco]

Hi, I have a gas furnace that gives me steamed heat through my radiators. If the electricity goes out this weekend (we're expecting an ice storm) will it automatically turn off or do I have to turn it off or what. All I know is that the last thing I do after turning it on for the season is flip on the electric switch on the wall. What does that do? Will the gas furnace work if the electricity goes out?

[Kolesar]

1. First question would be: Is your system actually a pumped hot water system?

Steam heat systems are found in houses and apartments from the early twentieth century and before. They have bulky looking cast iron radiators in each room. They are clever in that they can run with no electricity for pumping or for a control system.

Does each room of the house have a "convector" which is sometimes referred to as a "radiator"? It is a long "register" near the floor that looks like a copper pipe with a stack of a hundred or so stamped steel fins aligned on it like a zinc shish-ke-bab.

At the furnace, is there a large copper pipe running out of the "boiler" to a pump attached to a large electric motor? If the answer to both of these questions is yes, then you have a "pumped" hot water heat system.

[Chalco]

2. I'll try to answer that

My house was built in 1935. When I bought the house I had a furnace that used oil. The house had and still has steam radiators. When the oil furnace gave out in about 1984 I replaced it with a gas furnace. The radiators are still the same. Water flows into the furnace and steam is pumped out. I'm sure there's a copper pipe but don't know about a "large electric motor."

[Kolesar]

3. Ok. So you have a steam system and not a hydronic hot water circulation system

Now I am trying to figure out if your system can operate without electricity for the control system or to pump the steam (I doubt if it is pumped). Unfortuately, I am out of time this morning. There are better heating-writers on this forum than I who could take over.

I found a suitable article on Howstuffworks.com
http://home.howstuffworks.com/how-to-troubleshoot-a-hot-water-and-steam-distribution-system.htm

I think your system is called an "Open gravity systems" and it *may* be able to operate without electricity. But I don't know what that switch you mentioned does.

[Chalco]

4. I just went down and looked at the furnace.

It's a Burnham gas furnace and then attached to the front is a McDonnell and Miller pump.

[Chalco]

5. Just got off the phone with the plumber.

He said that without electricity the pump wouldn't push the steam through the pipes so there would be no heat and no point to leaving the gas furnace on. But he also said that I didn't need to shut down the gas furnace, just leave as is and wait for the electricity to turn back on.

Does this make sense?

[Kolesar]

6. Yes. That sounds like good advice

Contemporary heating plants are designed with a "fail safe" mode where if the electricity or gas gets cut off, the system shuts off the flow of gas. When the electricity is restored, it stays in a safe state. You won't have gas from a pilot light leaking out when you get back.

[Warpy]

7. Steam heat doesn't always rely on a pump

Pressure forces the steam into all the radiators. When the furnace clicks off and the steam condenses back into water, gravity returns it to the boiler.

However, if your system is thermostatically controlled, it will go out when the power does. It also sounds like you have an electronic ignition on your boiler if all you have to do is flip a switch to turn it on or off.

My advice is to plan to bake a lot of Xmas cookies during the storm and after. You can freeze them for a few days and they'll be as good as new on the day itself. Same goes for pies.

That's how and why I learned to bake. Electricity on Cape Cod in the winter was a very chancy thing, and when I lived in a place without a woodstove, the gas oven was my heat, at least in one room.