Bleeding Radiators with a Hot Water Cylinder

anotheruser

Previously, I've been able to bleed radiators, then open a valve under the boiler and add more water to the system. Lovely.
Now I live in a house with a hot water tank cylinder and a cold water tank above it in the loft.

There are no dials anywhere on the boiler or tank.

If I bleed the radiators, will the system just add more water automatically? If now, how do I add more? How do I know how much to add?

Thanks for any pointers!

southcoastrgi

You should have two tanks in the loft the big one is for the hot water the small one keeps your heating topped up, don't have the pump running when you bleed the rads as you could let more air into the system rather than letting it out

owen_money

southcoastrgi wrote: »

don't have the pump running when you bleed the rads as you could let more air into the system rather than letting it out

How so? Just interested as have read this before, but thought it wouldn't make a difference?

southcoastrgi

Depending on where the pump is located determines if the system is under positive or negative pressure, if you bleed the rads with the pump running & it's under negative pressure then it can suck air in