Corrosion since drain down?

[Anna Rack]

Just over a year ago I had a leak on one of the valves on my Boilermate 2000, so it was drained down and a new valve fitted.

On drain down, the water looked quite clean.

British Gas did the job and refilled the tank, but with no inhibitor, as apparantly that 'isn't part of the job'. Also I didn't think at the time to bypass the water softener we have fitted, so it was filled with softened water.

I complained about the lack of inhibitor to BG but all they would offer is a return visit to add it if I purchased it.

After a couple of weeks I added it myself, draining a few litres out and then adding 2 x bottles of Sentinel X100.

All is working fine apart from a clunk from one radiator when the heating cuts in. I thought I would bleed it thinking there might be some air trapped although there were no cold spots. I think it may have done this before but I can't remember.

I noticed that the water is now quite dark, similar to Coke.

Is it a cause for concern? Could it be linked to the previous drain down with softened water? X100 is ok with softened water according to the manufacturer.

Any thoughts appreciated.

 

[oz-plumber]

The clink is probably caused by the control valve on the radiator being installed on the return and not the flow.

Which valve heats up first - the valve that goes clunk or the one on the other side?

 

[Anna Rack]

Thanks.

The valve is on the correct side. It's always set to maximum and heats up evenly so it's not really an issue.
I was more concerned when bleeding that the water was quite brown despite having ample X100. It was quite clear when draining just over a year ago.

Would the drain/refill have contributed by stirring it up? It seems Boilermate thermal stores do seem to be affected by sludge etc