Have a new weil 155 ultra gas hot water boiler (no external hot water) For experiment, the temp outside was 45 deg and home temp was 62 deg. The water temp in boiler was reading 66 deg. I turned thermostat up to 71 and about an hour and a half to two hours later the house was heated including basement and two upper floors to correct temp. I estimated the gas used at 3-3 1/2 cubic feet or about 4 dollars. What I am unsure about is after the home is heated the water temp in the boiler will continue to fall and fall from say 155 to 90 or less and then the boiler will fire for a while and maintain temp. Over a period of say 6 hours this may consume 2-3 more cf of gas. According to the guy who installed it, he thinks the system has 25 gallons or so of water, but I dont think he really knew. I;m hoping one of the great yahoo experts can tell me this scenario sounds correct/ Thanks
the installer sounds about right keep in mind it is probably cheaper to heat the water when the stat calls for heat than it would be to maintain the water temp. remember to maintain the temp the boiler would be kicking on and off could be a lot higher.
I have read your question a few times and I am unsure of what you are asking. Please clarify. Thanks, Newt
Old boiler systems would maintain the heat inside of them all of the time, that is inefficient. Your new boiler will only heat the water when there is a call for heat from any of your t-stats and the circulation pumps is on, causing water to flow through the boiler, this is a safety issue so that the water does not flash to steam inside the heat exchanger. The fluctuation in temps you see are normal and expected
