Cold rads

[heathi099]

Any help would be appreciated.
I have a 3 floor house with 17 rads. Potterham suprima boiler, boliermate 2000.
I had pumps and heat exchange replaced last year, engineer didn't put inhibitor in the system after the fix (claimed wasn't allowed to go into my loft to put inhibitor in feed tank) but everything worked.
This winter rads work upstairs and two small ones working downstairs, 5 downstairs rads are completely cold. Today I removed 3 of them, cleaned out sludge, I expected them to be blocked due to lack of inhibitor and they were petty dirty. Cleaned them out multiple times with a hosepipe. Checked the flow on incoming and outgoings valves. Good run of black water but ran until clear. Reconnected rads, bled, added fernox cleaner into an empty feeder tank, removed TRV's and freed pin. Opened lockshield on hot downstairs rads a small amount, opened lockshield on cold rads almost the entire way. Incoming pipes hot but rads still completely cold. Have a power flush booked next week. Any advice on how to resolve don't want to pay a load of money to be in the same position. Any thoughts?

 

[livingstoned]

Shut the radiators which work, that should get water round the others. You may have airlocks.
Three floor houses can be porcine to balance.

pumps

what's your system exactly. More than one pump??

 

[heathi099]

Just one pump but it new and has been sufficient previously. Should I close just the TRV or the lockshield too on the working rads. All of of them or just majority?

 

[DavoUK]

I had a similar thing. I turned off all rads except one. Left heating off overnight. When heating turned on in the morning, there was lots of gurgling and the rad started heating up. Repeated this the next night for the next non-working rad.