Thermostats and oversized hot water boilers

Jim_65

What type of heat emitters do you have? Has anyone calculated the heat loss of the structure?

I am not positive about the Honeywell T-stat having those capabilities. I would suggest looking into some Outdoor Reset Controls from Tekmar.

Phil_13

Theromostats and oversized boilers

I have just moved into a "old" house, with a large Weil-McLain EG-50 hot water boiler. It seems to me that the furnace at 144,000BTu/hr is oversized for the 2300 sq ft home.

Does it make sense to somehow specify some minimum boiler run time to increase efficiency? That is, have the boiler turn on at one temperature, say 65 degrees and then turn off at 70 degrees? It seems that such cycles could increase boiler cycles and efficiency.

Are there thermostats that do this? I have bought new "smart" honeywell thermostats. They have a setting for hot water boiler heating in programming mode. Does the thermostat do something like this?

Does any of this make sense?

Thanks,

Phil

Phil_13

Theromostats and oversized boilers

I have just moved into a "old" house, with a large Weil-McLain EG-50 hot water boiler. It seems to me that the furnace at 144,000BTu/hr is oversized for the 2300 sq ft home.

Does it make sense to somehow specify some minimum boiler run time to increase efficiency? That is, have the boiler turn on at one temperature, say 65 degrees and then turn off at 70 degrees? It seems that such cycles could increase boiler cycles and efficiency.

Are there thermostats that do this? I have bought new "smart" honeywell thermostats. They have a setting for hot water boiler heating in programming mode. Does the thermostat do something like this?

Does any of this make sense?

Thanks,

Phil

Scooter Libby

For a really old house of that size, 144,000 BTU may not be so bad. It depends on the insulation. It is probably oversized but not obscenely oversized.

No thermostat allows a 5F swing, but when you set the number of cycles per hour to be smaller, you cause the temperature swing to be larger. Your Honeywell thermostat may say to set "12" for electric heat, "6" for forced air and "3" for hot water heat. That number is the number of cycles per hour. You can also choose "1" for steam, even though you have hot water, and it'll work OK except you'll get a larger temperature swing.

If your thermostat doesn't have these numbers, but allows you to choose "steam" vs "hot water", go ahead and try "steam".

phil_14

The house has old steel radiators. No, no heat loss calculations have been done.