Central heating pump runs all the time.

[jasumner]

Hi, I have a 20 year old Myson oil boiler with very simple wiring used for heating radiators only. The boiler is controlled by programable timer and a room thermostat. When the programmer switches the system on the pump runs continuously until the end of the programmed time. The boiler switches in and out as called for by the boiler stat and room stat as they are wired in series. I cannot see any way looking at the wiring diagrams for the boiler to switch the pump off when the boiler switches off. Is it normal on old installation for the pump to run all the time. I could wire the room stat in circuit with the pump instead to shut the pump down and leave the boiler stat to shut the boiler off.
Do I leave well alone until I replace the boiler (I know its well overdue)
Any advise would be well appreciated.
John.

 

[sambotc]

Hi,

It is supposed to run this way as the water needs to circulate to lose heat in order for the boiler to fire back up once the demand is called for again. Other wise the boiler would be off for long periods as the water that is inside it slowly cools down whilst the house gets cold. A room stat will work as the pump will come on as soon as the air temperature changes but if you intend on replacing soon, i wouldn't bother!

Sam