Dirty Water in Radiators after Flush

Roaming

We have a glow worm 24cxi condensing combi boiler fitted in the kitchen.

Think there used to be a water tank in the lost but it was redundant when we bought the house. Got a boiler inspection certificate from February this year wit all pass.

keystone

Right no F&E tank with a combi. I was fishing previously to see if it was pumping over which can be caused by a blockage and when that happens you circulate aerated water which gives rise to more air which can also cause the banging.

My favourite suspect is sludge even more now.

Cheers

Roaming

Thank you Keystone!

So, what is your advice on sorting this out then? I would be inclined to agree on the sludge as the first time it started happening was when I accidentally hit one of the downstairs radiators with a ladder whilst turning it around. The radiator and the pipes going/coming from it went crazy vibrating.

Since then, the occurrence of the noise has been sporadic and random in terms of which radiator kicks off.

Also, how do you suggest I address this with the plumber? I feel a bit awkward straight out suggesting to him that he didn't actually do a flush of the system.

Canucklehead

Hi.


Regarding the TRVs.
To expand on Ruski's post.
If you turn off a TRV,or push the pin down, rapidly it will produce a 'clunk' when the water is flowing through the valve. The flow of water 'slams' the valve shut.

You need to check the direction arrow on the TRV matches the flow of water ie: the TRV should be the flow end, that's the end that heats up first.

If all the TRVs are on the 'wrong' end you might find the flow and return were swapped at the boiler end when it was converted.

A uni directional TRV with the flow in the wrong direction will produce various whistles and clunks as it tries to shut down when the room temp rises.

IMO the best way to flush is from the flow and return under the boiler thereby leaving the boiler out of the circuit.

Fit a magnetic filter to the c/h return and add inhibitor.

GSR.

keystone

Roaming wrote: »

Also, how do you suggest I address this with the plumber? I feel a bit awkward straight out suggesting to him that he didn't actually do a flush of the system.

Yes I could understand that but on the basis that:

Roaming wrote: »

The plumber we engaged advised that a system flush, refill and rebalance and bleeding of radiators would sort out the problem.

but it seems that he probably didn't actually do that despite being contracted to do so I'd let it lie fallow and look for someone else - provided he hasn't charged you a small fortune thus far. Take note of what Russ and CH have said about the TRVs.

Cheers

gas4you

More often than not an old TRV fitted against the flow of water will sound like a pneumatic drill when it is shutting. They can be fitted on either the flow or return, but as said, the arrow MUST match the water flow direction.

When you hear this noise, quickly go and fully open any TRV you feel may be causing it. If it stops, you have found your answer.