Boiler sizing/Control/cycling question

Tundra

You have a heating "system" not just a boiler. First if your boiler is too large your standby losses will be extravagant. You will control your system depending on what you are trying to accomplish. If you are worried about condensation you might place a control on the return that would close your zone valves. Or, you might have a control on a return that will turn you burner on and off depending on return temp. Except for the System 2000 return temp. aquastats are fairly rare in the residential systems I deal with.

Mike Newbie

I had a discussion with our company's heating system salesman where he said that if a (residential) boiler is installed that is oversized, or there is not enough baseboard, the water comes back too hot. This I can understand. (I think he was talking about a gas fired boiler)

But then he said that there is a control that detects this, (return water coming back at 175°) and it causes the burner to shut off, and then the burner comes on again later, and will continue to "short cycle", wasting lots of fuel. I told him that the only thing I know is that an aquastat will shut the burner off at 180°, and the burner will come on again when the water temp drops below 160° (approx), so it will not be short cycling.

Can anybody tell me what kind of control my salesman might be talking about? I think that there is a possibility that he can be wrong, but maybe he has seen this happen. He said that he has seen a system that the boiler is twice the needed btus, or that there were only 20' of baseboards.

[Deleted User]

sounds to me like he

is talking about the aquastat...yes it would short cycle if there isn't much water to "chew" on..a buffer tank could aways be installed tho to handle this..that would give the boilers burner and aquastat something to chew on.