Heat anticipator and boiler cycling

chakil

Hi,
In their T87 Honeywell states that a higher number on their heat anticipator scale gives a longer burner on-time.
That's because the heat anticipator pre-heats the thermostat less at higher Amps numbers, so the thermostat doesn't turn off "early" - it turns off "later" so the heating system will remain on longer.

I don't understand how heat anticipator can longer or shorter boiler cycling ?

I do understand that the thermostat would puts out the most heat, this warms up the thermostat's room temperature sensor and therefore tells the thermostat the room is up to set temperature earliest -- but that would also tells the thermostat that the room is not enough cold and burner would kick off later
so the lenght of the cycle doesn't change after all ?!

Sorry my English is not good.

Jamie Hall

The whole idea is to get the thermostat to warm up a little faster -- or slower -- so that it shuts off the heat at the right time to let the residual heat in the radiators or whatever to bring the room up to the set temperature. The anticipator, however, does nothing to how fast the room -- and hence the thermostat -- cools off again. Therefore, an anticipator setting which shuts off the heat sooner tends to give a longer off time for the cycle. There are, however, many other factors involved to determine both the length of the cycles and the total run time of the system.

chakil

Jamie Hall said:

The whole idea is to get the thermostat to warm up a little faster -- or slower -- so that it shuts off the heat at the right time to let the residual heat in the radiators or whatever to bring the room up to the set temperature. The anticipator, however, does nothing to how fast the room -- and hence the thermostat -- cools off again. Therefore, an anticipator setting which shuts off the heat sooner tends to give a longer off time for the cycle. There are, however, many other factors involved to determine both the length of the cycles and the total run time of the system.

Thank you very much for your reply
I think i have understood now how heat anticipator affect the boiler cycle length, it gives a longer off time for the burner because it is on more than he needed to be to reach the set point room temperature.