Loads of problems - combi boiler

[bilbrook]

I'll try and be brief, have moved into new house, had boiler inspected and is now playing up. Boiler is Ocean Combi (can't remember spec) and serves 12 rads (11 of which thermostatic valves). Now having three problems:

1. HAMMER; water hammer on cold water. Local mains (appears) to have increased in pressure recently.

2. BOILER NOISE; on turning off HW from any tap boiler makes short (1 sec) ascending "whistle".

3. INTERMITTENT HW; not had combi before, have been told about this but find that for example shower or bath tap can be running with loads of HW but then will turn cold (with nothing else happening) in house. Can only get HW back by turning off then waiting and sometimes get HW back.

Any ideas?? Took age to find anyone to service Ocean, do I just rip it off the wall and start again with new boiler??

 

[COG]

The first two faults together sound as if you have a dead leg somewhere on the system (air trapped in the end of a dead leg pipe), as for the intermittant hot water it could be anything, all combis basicaly work the same so you should be able to find an eng have you got a copy of the instructions with the flow charts in etc

 

[oilman]

I am probably wrong, but the boiler whistle sounds like a scaled up boiler and the cold hot water tends to confirm this as it is probably overheating and causing the thermostat or other temp control to operate.

 

[bilbrook]

Thanks for quick replies

Could be scaled up I suppose, doesn't seem to be too bad an area for scaling, but then I don't know how long the boiler has been in. I assume if its scaled up then thats a new boiler then. The hammer has only started recently, would this still signify a dead leg pipe? Daft question is a dead leg pipe just a dead end, a pipe that has been cut off/sealed when they put in the new rads/pipework etc If it is a dead leg with trapped air, how can you get this air out? I've had a look at the instructions etc but weren't really any help, but now you've given me a few more ideas I'll go back and have another look. Thanks alot for the ideas.