Cold radiators

[Morris s]

Hi, I have a sealed system running from mains pressure with a large Sadia high pressure water tank to store hot water. My house is a town house on 4 storeys and the downstairs rads are cold. The boiler is on the second floor and the tank and pump on the third. The rad in the top bedroom, fourth floor, is also quite cool. I was wondering if the thermostatic valves had failed, but i have freed the pins and still no result. I think the pump may be on the way out. Is changing it the same as on a vented system, bleeding down the system etc, and refilllig with the filling loop. I have done various jobs on vented systems before but an worried about working on a sealed system. Any special things to worry about with one of these system, or hints would be much appreceated.

Any ideas folks?

Thanks

 

[chrishutt]

You don't say what boiler you have. Might be useful.

 

[Morris s]

Sorry its a Glowworm Ultimat 40FF, Its not a combi boiler I think its a condensing boiler?

Cheers