Expansion vessel leaking or blocked heat exchanger

[hary_j]

Evening gentlemen,

Stopped at my last job today, it was a vaillant eco tec plus 837 combi. Boiler is building excessive pressure, whether it be on DHW or CH mode.

Upon firing up on CH mode, pressure rises to maximum and prv lets by at 3.5bar all within around 5-10mins of being operational. I can hear some clunking & screeching as this takes place and eventually the boiler stops, no fault codes present.

The F & R inside the boiler going up to the main heat exchanger, flow is scalding hot where is the return is just adequately hot.

I checked the expansion vessel and this had zero air pressure, no water/moisture came out the shraeder valve either. I then isolated the both F&R valves beneath the boiler and pumped the vessel to just under 1 bar pressure. This held until the boiler was fired up again and then boiler's prv began to let-by, after 5-10 min of operation.

Possible issue's..

-Severely blocked main heat exchanger (very common in these)
-Blocked outlet connection beneath expansion vessel


Hopefully you guy's can throw some input on this.

Thanks

 

[sammathias]

Did you definitely turn the f+r valves back on?? Any banging present? Are there black rubber hoses on the f+r pipes internal...or isit a new model?

 

[sammathias]

Are you gas Safe? If so send your number to @ShaunCorbs

 

[hary_j]

Yep, did turn them back on, they were a little stiff, which worries me if they are maneuvering well enough. Banging, clunking n thumping, did return but it was a little milder. No rubber hoses on this, most likely the newer edition with solid plastic pipes

 

[ShaunCorbs]

are you gas safe reg?

 

[sammathias]

Copper pipes you mean? Do the rads get hot?

 

[hary_j]

Are you gas Safe? If so send your number to @ShaunCorbs

I've just recently qualified, although i've been doing plumbing for almost 14 years, my registration is in process with gas safe as we speak. Therefore i'm working with a close friend who is for many years, but isn't very technically minded on repairs unfortunately.

 

[ShaunCorbs]

I've just recently qualified, although i've been doing plumbing for almost 14 years, my registration is in process with gas safe as we speak. Therefore i'm working with a close friend who is for many years, but isn't very technically minded on repairs unfortunately.

did you friend come with you on this last job?

 

[hary_j]

Copper pipes you mean? Do the rads get hot?

Rad's aren't as warm as they used to be, which is what the customer has explained

 

[hary_j]

did you friend come with you on this last job?

of course, we work together and always have been, don't do illegal work 😵 never have done.

 

[sammathias]

Unfortunately mate your either registered or not. The only process you will be in with gas Safe is paying the fee then instantly becoming registered... Hate to be one of them people but can't comment much more other than potential circulation issue but you have already gathered that.

 

[ShaunCorbs]

thread closed due to not gas safe atm