Lack of Hot water

[andyapanel]

Hi everyone, my first post is a plea for advice.

Over the last month, the flow of water through the hot system has slowed accompanied by interesting gurgles as the water surges back and forth.
Its an indirect hot system, that I put in 20 years ago.

I thought it might be an air lock, but it has not responded to standard treatment.

Ive sent mains pressure water through(bypassing the header) and the flow is fine. The expansion pipe from the top of the hot cylinder overflows almost immediately the mains is connected.

I think I have a blockage (scale?) in the pipework between the loft and the bathroom. Ive put some acid down, but it doesnt seem to have done much, tho it did fiz a lot.

Does this make sense, or should I be thinking of something else, such as a blockage in the hot cylinder somewhere?
A few months ago I replaced a T junction in the boiler feed which had become silted. I know they are not connected, but the symptoms are analagous.

 

[namsag]

Top connection on cylinder is the favourite they get quite a build up of scale on them, remove and clean

 

[andyapanel]

will try

 

[bengasman]

..A few months ago I replaced a T junction in the boiler feed which had become silted. I know they are not connected, but the symptoms are analagous.

Chances are that the entire system is badly clogged up and needs rigorous cleaning

 

[andyapanel]

How?

 

[namsag]

Loads of CH systems are perfectly ok and clean even if the cold feed has blocked at some stage

 

[bengasman]

Loads of CH systems are perfectly ok and clean even if the cold feed has blocked at some stage

Agreed, 1% of all English open vent systems is still an awful lot of boilers.

 

[andyapanel]

Ive got that connector out and its a bit limy. Having a cuppa then popping a new one in. Pipework leaving the top of the tank seems fine.
IF that doesnt do it, does my original theory about the hot pipe to the taps being limed up "hold water" ??
And -how do I clean it out Bengasman ?

 

[andyapanel]

New connector in. No improvement.
Next idea, please

 

[bengasman]

And -how do I clean it out Bengasman ?

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