We replaced the thermostat on our furnace

Our boiler system is getting up to the desired heat but then when it turns off we have to flip the switch on the wall off for the boiler - then back on - then you hear the clicking and the furnace begins to send out heat through the pipes again - what causes it to need us to flip the switch so it clicks and restarts?

Exact Brand of boiler?

Exact model number of boiler?

Exact brand of thermostat?

Exact model number of thermostat?

Brands and model numbers of all controls hooked up to the boiler at the boiler and elsewhere. Please include any zone valve manufactures names and model numbers.

Without exact complete info we cannot be of much help.