Cold feed sludge removal. Good way?

[stuarthall]

Hello...

My heating (on in the mornings currently) and hot water are taking longer to heat up. I suppose this has been gradual but now is time to act I think.

I have read about possibly having a blocked cold feed (from this site).

After looking into my F & E cistern I have noticed a bit of gooey sludgey type mess at the bottom (not too much but a bit) and also around the area where the cold feed pipe enters the system.

I want to clean the cold feed and F & E cistern out. So after reading posts on here, am I right in thinking the best way to get the crap out of the cold feed / H piece area (these get blocked commonly I have also read) is to undo my circulating pump connection (the top one as it is installed vertically & pupmojg downwards) and poking it through with a long piece of wire until clean?

I have a snake tool that is ideal for this - a flexible but strongish metal rod!!

On re-installing the pump I believe I should use new washers to create a watertight seal (or in my case a washer) - what size do I require for a pump union? I don't have to buy a new pump do I? If the washers only come with the pump will this mean I have to?

Thanks all for your time and help.

SH

 

[nickso]

i find the best way is to remove the cold feed connection completely. rodding out the gunk isnt guaranteed to get it all and some of it may be quite solid and difficult to remove. put it all back together with compression fittings and its a doddle to remove again in five years when it will probably need doing again.

i usually remove the f+e tank from the loft if its awkward to clean whilst in situ and get the customers hose and a sponge on it.

pump washers are available on their own. you can reuse the originals if they are in good condition but for all the price of them its sensible to change them. try your plumbers merchant or B+Q and the like.

dont forget to put a tub or two of inhibitor back in when you refill it.

 

[JohnD]

You have not said anything that shows your cold feed is blocked. So work to remove a blockage is not yet justified.

1) Is water circulating through your system?

2) Does water squirt out forcefully when you bleed every radiator?

3) Have you got a 3-port valve, (or 2-port Zone valves) and can you tell (by feeling which pipes are hot and which are cold) that it is operating correctly?

4) Have you got microbore pipes?

5) Have you got TRVs? Do you have reason to believe that some of them are stuck?

If you have not got a blockage, you can use chemical cleaners.

 

[stuarthall]

Thanks for your replies

John - I have bled the rads and most of them have not much water coming out and not at any pressure at all. This led me to believe it is a blocked cold feed, especially now I have seen the sludgy muck in the F & E cistern as well.

Water does circulate (or it must do) as the pump is working and heating and hot water do come on - only they take longer to warm up.

I have a 3 port valve - Honeywell. To be honest when I only have hot water on, the pipe leading to the heating side also feels warm - no heating comes on, I just believe this is through conduction of the copper pipes/metal valve!

I have normal copper pipes (15mm and 22mm diameter).

I have TRVs on most rads, except the bathroom one. They must be OK as the radisators warm up, but as above, slower!

Should I drain down the whole system first (or as much as will drain down).

I have heard about chemical cleaners which can be added to the F & E cistern. Fernox and Sentinel do sludge removers - but where will it all go? Maybe it will circualte round my whole system and damage the boiler heat exchanger too if i add this?

What size washers are used for pumps? I will purchase some today.

 

[JohnD]

If the F&E pipe is actually blocked, then you can drain a bucket of water out of a radiator, and no water will be drawn down from the F&E cistern. If you bleed radiators, they will have little pressure, and although water will squirt out of the downstairs ones, nothing may squirt out of the upstairs ones. Is this what you have got?

If it is obstructed but not blocked, water will be drawn down slowly, and the radiators will be full, and under pressure.

If it is blocked, adding chemicals to the F&E will not help because the blockage will prevent them getting into circulation.

Sometimes you can push a blockage out by water pressure, as in //www.diynot.com/forums/viewtopic.php?p=771846#771846

If you use a chemical like Sentinel X400, it is not aggressive or corrosive, it simply softens and breaks down sludge and sediment so that it can be carried round in the circulating water, and drained out after a few weeks. It is not harmful even if you leave it in place indefinitely (though this would not remove the material from your system, and after 4 weeks or so it would lose its effect)

If you are doing some home plumbing, and can afford £100, this is a good time to add a Magnaclean to a vertical 22mm Return pipe. It will trap any black sediment carried in the water circulating through it. You will be amazed and delighted to see how much it collects. It will prevent future blockages of black sediment. as a householder (not a plumber) I would say it is an easy plumbing job, and very effective. You need to be drained down when you fit it.

 

[Agile]

The blockage at the junction with the system is a calcium based compound which is VERY hard. Poking will do no good!

The only way is usually to cut out the pipework and clear it with a hammer and chisel or a masonry drill. It can sometimes be replaced using compression couplers.

Tony

 

[stuarthall]

Thanks all for your help.

I think I have a partial blockage, as the radiators upstairs do bleed a bit, but the water is not of any real pressure (not as it normally would be) and also after a few seconds it just stops. I take it this means a partial blockage?

I may have to drain the rest of the system, cut the cold feed out after bailing the water from the f & e and replace then? I can cut/bend and join copper pipes. Should I replace the cold feed and vent or just cold feed and Tee piece connection to the vent?

Is compression fittings OK for pumped heating pressure?

After doing this do you recommend I thoroughly flush the system through a few times until it runs clear and then add an inhibitor to the F & E cistern?

Thanks all of you for your help.

 

[JohnD]

the blockage is most likely in the Tee, so this is what you have to cut out and replace. You do not have to replace the rest of the pipe. You can replace it in compression.

You can verify where the blockage is by holding a magnet against the copper pipe, it will be attracted to the black magnetite sediment inside.

if you know you have a sludge and sediment problem, you ought to give it a chemical clean with X400 or similar which will soften and loosen it, not just a plain water flush.

if you are doing some home plumbing and can afford £100 this is a good time to fit a Magnaclean on a vertical 22mm return pipe. You will be amazed and delighted to see how much black it collects. It will prevent future black blockages.

I am a householder not a plumber.

 

[Deleted member 105431]

if you are doing some home plumbing and can afford £100 this is a good time to fit a Magnaclean on a vertical 22mm return pipe. You will be amazed and delighted to see how much black it collects. It will prevent future black blockages.

definately agree with that. will pay for itself long term.

don't forget to inhibit system afterwards (X100)