Noisy Vokera Compact

[djk]

Our Vokera Compact is one year old - the rads and pipework somewhat older. The boiler has been noisy for some time, on looking through the FAQ's the term kettling seems to describe it but there are also loud bangs throught the day but especially on startup.
Recently, when the hot kitchen tap is turned on we get a few seconds of very hot water then the flame in the boiler goes out. If the tap is left running the boiler tries to restart but cannot even though the'hot' water is ice cold by now. When the tap is turned off the boiler re ignites and if we leave it a few seconds before opening the hot tap again we can get another few seconds of hot water before the system shuts down again. The problem cleared itself a few weeks ago but this was only temporary and things are as bad as ever again.
Another source of noise is in the loft from what looks like a small inverted gas cylinder - ?something to do with the pressure in the system? I would like advice on how this problem should be properly fixed, as I'm sure my landlord will go for the cheapest option.

 

[Paul Barker]

Check the pressure guage when the system is cold, should be above no 1 below no 2. Top up via filling loop to 1.5.

Apart from that there may be a problem with sludge in the system, which would require urgent treatment. If it is sludge it may be too late to save that heat exchanger it may be however possible for a professional to save it with his powerflush and some strong chemicals.

If that's the problem the cheap solution won't work, it will cost the landlord a lot of money to pay for the fact he used a poor installer....