Radiators now cold after using Fernox DS40!!

[Lindzlashes]

Hi
we have had a problem with our heating system since moving in a number of yrs ago, that has got progressively worse. The upstairs radiators are hot but down stairs are freezing cold! We have had a new pump fitted, the radiators bled and balanced and they are still cold!

They get slightly warm if I turn the temp of the boiler right down.

The other day we turned all the radiators off upstairs to force the water downstairs, to hopefully unblock any blockage. The radiators got hot and after a while we turned the radiators on upstairs. For 2 days the system worked normally, then the radiators down stairs went freezing cold again!

We purchased some fernox DS40 and put that into the system tonight via the bathroom radiator. Now after a short time all the radiators are cold even the upstairs ones! I have bled all the radiators incase of an airlock, but still the problem persists!! Please could some one suggest what the problem may be and how we could fix it?

Any help would be greatly appreciated.

Lindsey

 

[Hugh Jaleak]

What type of boiler/system do you have?

 

[leakydave]

It sounds like you have air in the system now, and the system needs balancing.

 

[Lindzlashes]

Its an Ariston combi-boiler.

 

[Hugh Jaleak]

System pressure correct? (Should be between 1-1.5 bar.) If nothing is working is the thermostat calling for heat?