Vaillant combicompact ecomax - excessive noise from cold

[Skysparky]

HELLO ALL,
WHENEVER THIS BOILER STARTS FROM COLD IT "POPS", "BANGS", AND "MOANS".
IT ONLY APPEARS TO DO THIS WHEN HOT WATER IS SELECTED AS WELL AS HEATING. - THE HOTWATER OUTLET IS CONNECTED TO A MEGAFLOW CYLINDER VIA A MOTORISED VALVE AS WELL AS DIRECT HOT TAP FLOW.
WOULD I BE CORRECT IN ASSUMING THAT THE BOILER DHW HEAT EXCHANGER IS KETTLING ??
CAN ANYONE PLEASE ADVISE AS TO THE ACTION NEEDED TO RECTIFY ?
CAN THE DHW HEAT EXCHANGER BE REMOVED AND DESCALED MAYBE ?
IS IT LIKELY THIS COULD BE A FLOW PROBLEM OR ANYTHING MORE SINISTER.

PLEASE HELP - I NEED TO BE ABLE TO SLEEP PAST 05.30 WHEN THIS HAPPENS !!!

THE BOILER IS APPROX 7 YEARS OLD IN A HARD WATER AREA - BUT HAS GOT FERNOX INSTALLED.

ANY HELPFULL ADVICE WOULD BE GREATLY APPRECIATED -

MANY THANKS

 

[Billy Bob Bob]

could be sludge you may need a de-scale vent some water from a rad what colour is it?are you getting constant air and yes if you live in a hard water area you may have a scaled up plate heat

 

[Skysparky]

Thanks for your reply Gas Man,
The water from the rads is clear - I am getting constant air yes and losing a small amount of pressure.
Can I add a de-scaler and if so what would you suggest ?

Thanks again.
Skysparky

 

[Billy Bob Bob]

as a descaler fernox or sentinel x 800 the later can be very aggressive next time you bleed air out of a rad very carefully see if it burns it wont be air it will be nitrogen a side effect of corrosion

 

[Skysparky]

Cheers Gas Man - I will give it a go - Thanks.

Skysparky

 

[jawadh]

Hello there, I went to a customers house where they have a turbomax plus 828 and the problem they have is the 2 downstairs radiators only get hot from the top and not the bottom. I have inserted sentinel x400 and left it for 2 weeks. All the radiators are less than 2 years old and only the downstairs pipework is new. I will be going back to the house in the next couple of days to drain out the chemical. If this does not solve the issue I am in 2 minds whether to tell the customer it is a poor pump or needs a power flush. Also I failed to mention when the customer had the rads and the downstairs pipework redone the installer never inserted inhibitor.