Flush (not powerflush/drain) CH system

[adi1]

Hi
I want to flush CH system after adding x400 and leaving it for a 3-4 weeks.
I'm planning to open drain valve while opening the mains water into CH system, hence flushing (not draining), one rad at a time. Correct me if I'm wrong.
My challenge is that automatic bypass valve will not allow proper flushing as the fresh water will escape through abv. Am I right in thinking this?
What setting should I leave on abv 0.1 - 0.5 bar?

Any other suggestion?

Boiler flow with abv

• adi1
• 13 Feb 2021

 

[oldbutnotdead]

First (important) you should isolate the boiler (so you don't push crud through the heat exchanger).
Second, ideally you'd take the bypass out of circuit so you (a) have full mains pressure to push any crud through the system (b) don't end up with a bypass full of gunge. Otherwise set it to the highest pressure it'll operate at or consider flushing in reverse (so return is at higher pressure than flow so bypass stays closed).

 

[Mottie]

Take the rads outside and flush manually with a hose pipe and a good shake.