expansion tank help-central heating

mrs_baggins

you will have to excuse my total ignorance on central heating matters but i will tell what i know!

i thought i may have had a sludge problem in my radiators. at first i thought they were not getting hot at bottom but now think that may be because they were not on long enough as yesterday they were hot all over. they also clank like mad sometimes but do not need bleeding.Anyway i got to thinking about sludge. house is 20 years old, as it may be a problem. after phoning a couple of places a powerflush would cost about £300 which i havent got but do not want to do it myself.

anyway this morning i decided to go up into loft and clean out the expansion tank. i think this is it anyway its about 2 gallon and water in there was warm and had a ball float? anyway i emptied it out all apart from about 1/2 inch water and cleaned it as best as i could and allowed it to refill. the watr that came out was very brown with a bit of sediment. Is this tank where i put that rust inhibitor stuff?

there was another tank but i never looked in this. For info I do not have a combi boiler its stored hot water in airing cupboard.

keystone

mrs_baggins wrote: »

anyway this morning i decided to go up into loft and clean out the expansion tank. i think this is it anyway its about 2 gallon and water in there was warm and had a ball float?

If the water in the feed and expansion tank is warm that implies that the system is pumping over usually due to a blockage. If its a magnetite blockage (which is likely on a 20 year old system) then no amount of powerflushing will shift it and the affected pipework needs to be cut out and replaced. The usual place is where the feed pipe from tyhe small tank in your roof joins the main circuit. That would also account for the poor radiator performance resulting from poor circulation. Pumping over puts hot water (which is then recycled back into the system) into the F&E tank where it is aerated. This contributes to and accelerates corrosion in the system.

anyway i emptied it out all apart from about 1/2 inch water and cleaned it as best as i could and allowed it to refill. the watr that came out was very brown with a bit of sediment. Is this tank where i put that rust inhibitor stuff?

Its quite normal for the F&E tank (cistern to some) to have brown sediment in the bottom and its not an enormous concern. The bast place to insert your inhibitor is via a radiator not via the F&E tank.

there was another tank but i never looked in this. For info I do not have a combi boiler its stored hot water in airing cupboard.

That will be your main cold water storage tank which supplies feed water to the cylinder and probably supplies most of your cold taps (except the kitchen).

Sorry to say this but I think you are going to have to find the pennies and get someone in.

Cheers

jayyar66

Hi there, you are quite right in your assumption. . . The small tank is indeed the feed/expansion tank for your heating system. (The larger one, and it will be significantly larger, is the feed tank for you hot water cylinder.) Firstly, the power flush. . . As long as your radiators get hot all over then the chances are that a power flush would be an unnecessary expense. As for the clanking noises, very difficult without hearing it, but a couple of possibilities are the pipework expanding and contracting or thermostatic valves fitted the wrong way round. Finally the inhibitor. . . If you were to put the inhibitor directly into the tank then because the tank is there to accommodate the expansion of water in the system and to replenish should the be a minor leak, the inhibitor wouldn't find it's way into the majority of the system. Far more effective would be to 1: Isolate a radiator using its valves. 2: Drain a couple of litres of water from the radiator. 3: Put the inhibitor straight into the top of the radiator. 4: Open valves & bleed then run system for an hour or 2 to ensure its fully dispersed.
Hope this helps.

mrs_baggins

thanks both for the reply. well on the good side it seems it was the expansion tank i cleaned but judging from what keystone says then as this water was warm verging on hot then there may be a problem somewhere. i dont feel at all confident on doing anything like this soit seems i may have to save up and get someone in. drat!!!

jayyar66

In that case, the usual advice applies, ask friends and/or neighbours for personal recommendations. Preferably of local independent plumbers/heating specialists. Try to avoid the likes of british gas etc.

jayyar66

Darn it!! Have just re-read my post. . . I mean, OBVIOUSLY, you want a plumber/heating engineer rather than a carpet fitter!! What I meant was preferably they should be local and independent!!

popeye2755

You may want to check that your heating pump is fitted correctly, I've seen a few fitted back to front. That can cause hot water to overflow into the F&E tank.

mrs_baggins

popeye2755 wrote: »

You may want to check that your heating pump is fitted correctly, I've seen a few fitted back to front. That can cause hot water to overflow into the F&E tank.

can you tell by looking at it as i wouldnt have a clue otherwise? i had new boiler about 2 years ago