rumbling heating

kitchensink_2

for the last week or two my heating has been making an intermittent rumbling noise. through a bit of web searching i think it may be sediment in the hot water tank or a thermostat may have gone - both resulting in water boiling somewhere (not sure). I've read it may be a good idea to flush the tank to get rid of the sediment and it seems I can do this myself - do people think this is a good first idea or am i best calling someone out? i dont want to turn a molehill (hopefully) into a mountain...:o

thanks

roger196

Is the rumbling the central heating system ( radiators) or the domestic hot water tank. Check that thermostat on tank / room thermostat has not been accidentally turned up.
Is your heating system open vented ( there are two cold tanks in the loft, a large one which feeds into the hot water tank, a small one which is the feed and expansion tank for the central heating system.
or do you have a combi with a sealed system ( usually no separate hot water tank).
Have you bled the radiators recently. Have you bled the pump.

kitchensink_2

thanks for the reply roger.:)

the boiler is an ideal classic rs260 and there are 2 tanks in the loft - a big one and a small one. Also have an airing cupboard with a tank in it. So I assume it's open vented?

radiators have been bled recently but not the pump - didn't know you could do this- could you tell me how please?

I think the rumbling is coming from the tank - I think it comes on when the heating is on compared to the hot water, but couldnt be certain of this. Next time it happens i'll have a closer look and listen.

eds. oh and the thermostat on the hotwater tank is set to 60, the boiler is on 5 and the thermostat in the hall is usually on about 20.
The pump (the red one in the airing cupboard) seems to have 33 settings marked |, || and ||| and it's on number 3

plumb1_2

It could be lack of water in the system, check the small tank in the loft to see if there is water in the tank.

kitchensink_2

thanks plumb - just done it and both tanks are full (to ballcock) - only thing is the smaller tank looks filthy inside - all scummy - i'm assuming thats not right??? :eek:

kitchensink_2

any other ideas please?

have a plumber coming over tonight - fingers crossed whatever it is wont cost the earth.....

roger196

As F&E tank filthy( the black sludge is ferric oxide from dissolving your rads from the inside), system needs draining, refilling and topped up with inhibitor. You can do this yourself.
Is there a 3 port valve( see www.screwfix.com part number 31421) in the airing cupboard. I am thinking that the valve maybe sticking when moving from CH to hot water and this may be causing vibration/rumbling. Can you tell us when the rumbling starts and where. Get someone to turn on a hot water tap while you watch and listen in the airing cupboard. Try this first with CH on, then later off.

kitchensink_2

thanks - we do have a 3 port valve - i'll try what you have suggested when OH back from work. Tried it on my own now and cant hear any probs in airing cupboard - only sound of water running.

The sound is like a rumbling/boiling sound that I hear mostly of a night coming from above when i'm sitting in the lounge. Hot water tank / airing cupboard is not directly above but in the vicinity.

I was thinking that the system may need cleaning/powerflush but i've heard this can be expensive. I'll google how to drain it myself and see how it looks.I was also thinking about draining the hot water tank?

We also have two showers and only one works. Other other will only work held at my ankles which doesn't really help! When you hold the shower head high it will only work when on full heat and it is way to hot. I thought this would be linked to the cartridge but now wondering if problems are linked. eg if there is sediment in the hw tank could it block the shower? Only thing is the other one works okay.

my head hurts :rotfl:

roger196

You only need a powerflush if the rads are blocked. The symptom of this is hot at the top and cold at the bottom. The sludge forms an inverted V in the rad. The cheapest way of removing this is to take rad off wall(drain system, turn off valves each end, use plenty of rag to catch black sludge), into garden and flush through with garden hose. repeat with remaining rads.
Another way is to remove one rad. Attach garden hose to each of the pipes, plastic hose when warm will just slip over 15mm pipe, fix with jubillee clip. One hose to garden tap, other hose to drain. Then flush each rad in turn with others turned off. Use lowest water pressure possible to get flow through as full mains water pressure can damage valves etc.
Let us know how you get on in the airing cupboard.
Is there an electric immersion heater at the top of the hot water tank. Has this been left on?

kitchensink_2

Thanks so much for all the detail
will have a feel of the radiators now - just turned up heating to get them warm! Don't seem to have an immersion heater in airing cupboard - only one fused switch and when i turned this off the heating turned off!

Will have a go at the tap thing later and report back

kitchensink_2

radiators have warmed up - some are hot all over eg in hallway but kitchen and dining room definitely colder at bottom - can keep hand against bottom but not at top...