newbie....help! hot water heating prob

[andy81b]

hi, my father has just had a new grant oil fired combi boiler installed, all has been well for week or so but all of a sudden when it heats the hot water there is now what sounds like air in the system. the noise kind of surges through the circulating pump but its not continuos, sounds every 8 secs something like that. when you switch off pump/boiler it stops instant. the system has auto bleed valves with the black screws about 1 turn undone. if you run both the central heating and hot water its fine?? no noise. its only noisey when heating hot water. Any help greatly appreciated.

 

[picasso]

if its a combi boiler how can you run the hot water and central heating at the same time? do you have a seperate pump/cylinder zone valves ect?

 

[mysteryman]

I am sure that is not what is meant.

Call the installer back - he is responsible for it for a year.

 

[picasso]

I am sure that is not what is meant.

Call the installer back - he is responsible for it for a year.

what does it mean if it doesnt mean what is meant ?

 

[andy81b]

ummmm.... it has expansion vessel upstairs near hotwater tank, pump is next to boiler downstairs. the guy who fitted it is a retired gent from down road, he fitted it and its since been checked and certified by proper inspector. like i say its been fine for week and all of a sudden it seems to have air in system when heating hot water but fine when heating hot water and cenral heating at same time? could it be water pressure?

 

[mysteryman]

So, is it a combi or do you have a hot water store elsewhere in the house?

You have come across a good reason for employing a professional installer!

 

[andy81b]

Totally agree my friend (proffesional installer) was gonna quote to do initial job but parents wanted local friend to do it.
Anyway.... There is a hot water storage tank in airing cupboard upstairs, boiler is downstairs, probably not combi i take it? It heats water only, doesn't store it in boiler.

 

[mysteryman]

It sounds like an airlock in the primary side of the cylinder. See if there is a manual air vent near the cylinder, and vent it with the system not operating. If it is a sealed [pressurised] heating sstem, you will need to top-up the pressure afterwards.