Sime Gas boiler running for long period after turned off

Younganddumb

Hi,

I've moved into a new house with a sime gas boiler, unfamiliar with gas, I've always had oil.
Boiler works fine, heats rads and water.

When the boiler is turned of (or when the timer runs it's course and stops) the ignition/flame goes out and it stops heating the rads/water, that's fine.

However the unit on the wall keeps going with what seems like a fan/blower for 4/5 hours.
From my guess work I think it's a cooling/ventilation system? As it seems to stop once the temp dial on the unit goes below 25 degrees. However as I said this can take 4/5 hours.
This is a quieter sound than when the boiler is on, however the boiler is in the house so it is noticeable.

I Feel sightly concerned heading to work in the morning with the system still running for an indefinite period.

I'm reading around Pcb? Thermistor?? The boiler is not broke per say.

I just had the boiler serviced when we moved in and the engineer said there was no issues.
Any clarity on this would be greatly appreciated to put my mind at ease.

Thanks.

DGOBS

Sounds like maybe the pump is running on, your in and around the right issue, and have seethe PCB do this in the past on that boiler.