Central Heating - sludge

[holidayinn]

Hi all, I’ve got an old school open vented boiler with cylinder in first floor and 2 tanks in the loft type system.

Shortly after the boiler fires it gets noisy and there’s a lot banging from the pipes directly above the boiler and around the pump, after 30 seconds to a minute boiler goes into standby (light turns flashing red).

Last couple of times this has happened, the boiler has been off for a day or 2 but then restarting it the system seems to work ok. It's been a couple of weeks and started playing up again yesterday.

Plumber thinks its sludge/debris in the pipes – recommends me to move to a combi system; other plumber recommended replace boiler and pump.

No-one really mentioned a flush or clean but not received full quotes yet.

The system is currently running ok, is there a quick fix? could I try an inhibitor? Or is it too late for that?

[wine~o]

I'd try cleaning the system myself, add fernox F3, (or F8 if the system is heavily sludged) to the CH header tank, run the system according to the instructions on the container, once it's had time to do its work, drain down the system and refill. runagain for a couple of days, drain and refill again, this time adding Fernox F1 inhibitor.