New(ish) CH system - need flushing?

[fiveminutejob]

My daughter's semi had a new Vaillant Ecotec boiler fitted with 10 new rads about 18 months ago. She tells me that after initial installation, there was a steady leak below downstairs floorboards on pipework to rads. Each day pressure dropped to zero until topped up with taps on underside of boiler. Installer repaired leak and refilled system. However she is pretty certain that he did not replenish inhibitor.

I'm happy to insert some inhibitor through bathroom upright rad, but would appreciate your advice on whether the system would have built up much dirt in 18 months if unprotected.

- Should it now be mains flushed before adding inhibitor?

- If so, should I try to isolate the pump first? How would I do that safely?

- If it does actually have inhibitor in it already, is it safe to add more (maybe of a different type)?

[Can't ask installer - as the guy who did the job is now abroad].

Thanks in advance.
fmj

 

[Steady]

It wouldn't do it any harm to give it a hot flush to see what the colour of the water is like then add inhibitor before refill. As far as I know there is no detrimental effect from mixing different inhibitors in the system water if you just wanted to throw some in. You don't need to isolate pump.

 

[fiveminutejob]

Thanks Steady,

That seems straightforward, so I'll do as you suggest.

fmj