Blocked pipes - will a chemical flush work?

[Lottie77]

I'm looking for some advice please if possible. My central heating pipes are blocked with sludge and my usual plumber says that I need to get the whole system re-piped.

I have 10 radiators running off a one pipe system and the pipes are all 15mm. I've had the baxi engineer come out and look at the combi boiler and he said the pipes are blocked with sludge which is why the heating isn't working. He recommended a chemical flush (and said that people would try and sell me a power flush but they are more expensive and not necessary.) He said the return flow isn't getting hot so must be really blocked.

When I spoke to my usual plumber he said that all the pipes needed changing to 22mm pipes and made into a 2 pipe system and that either a chemical or a power flush was unlikely to shift the blockage. I don't really have a clue about any of this and just have to go on what is recommended so I was wondering what other people think?

Is it worth me trying a chemical flush or a power flush? I know it'd probably be best practice to get the pipes all changed but I really can't afford it! What I don't understand is that the central heating has been working (it doesn't ever get that hot) since the boiler was installed in 2014, so if I get it flushed then surely it will go back to work in the same way?
Hope someone has some good advice - it's getting colder! Thank you.
Charlotte

 

[Harry Bloomfield]

A chemical flush can only work, if it can makes it's way along to the blockage. If the blockage is complete, it's unlikely it will work. If your pipes are that bad, it's also likely the boiler is also blocked.

The single pipe layout was dropped many years ago, they were less costly to install, but much less effective, more problematic, and less efficient to run, so your plumber is correct - you really need to be converted to a two pipe layout.

Pipe and radiator flushing, can be a DIY job. A matter of running lots of water through each pipe, radiator and the boiler to clear any obstructions.

 

[JohnD]

Is it actually blocked? If so, too late.

If not yet blocked, a chemical can loosen the sludge so that some of it can be drained and rinsed out. A DIY chemical clean is so cheap and easy that it is usually worth a try. IME a Magnaclean or similiar should also be fitted to trap more of the sludge that has been loosened but remains after the drain and rinse. It can capture whatever is circulating to prevent it settling again.

 

[JohnD]

Is it actually blocked? If so, too late. If not yet blocked, a chemical can loosen the sludge so that some of it can be drained and rinsed out. A DIY chemical clean is so cheap and easy that it is usually worth a try. IME a Magnaclean or similiar should also be fitted to trap more of the loosened sludgs that remains after the drain. It can trap circulating particles to prevent them settling again.

 

[amcluesent]

If you wanted to try and DIY it, you could lock off the valves to each radiator in turn, take outside and flush through with a hose pipe. Tap the metal with a soft mallet to help dislodge deposits. Remount rads and oven valves then rent a power-flush machine and hope the higher pressure from its pump will dislodge sludge in the pipes to restore circulation.

 

[JohnD]

Use the sludge-loosening chemical first.

I'm very happy with X400.

 

[Lottie77]

Is it actually blocked? If so, too late.

If not yet blocked, a chemical can loosen the sludge so that some of it can be drained and rinsed out. A DIY chemical clean is so cheap and easy that it is usually worth a try. IME a Magnaclean or similiar should also be fitted to trap more of the sludge that has been loosened but remains after the drain and rinse. It can capture whatever is circulating to prevent it settling again.

A couple of the radiators upstairs were getting hot and the ones downstairs were room temperature rather than ice cold like when the heating was off - so does that mean it's not completely blocked? How do you use the DIY chemical clean. Sounds like it's worth a try but would I need a plumber to do it (I'm a complete novice!) Thanks JohnD

 

[Lottie77]

A chemical flush can only work, if it can makes it's way along to the blockage. If the blockage is complete, it's unlikely it will work. If your pipes are that bad, it's also likely the boiler is also blocked.

The single pipe layout was dropped many years ago, they were less costly to install, but much less effective, more problematic, and less efficient to run, so your plumber is correct - you really need to be converted to a two pipe layout.

Pipe and radiator flushing, can be a DIY job. A matter of running lots of water through each pipe, radiator and the boiler to clear any obstructions.

A couple of upstairs radiators got hot so does that mean the blockage isn't complete? Ive had the baxi engineer around already (as the boiler is still under warantee) and he cleaned the filter out and just said I needed a chemical flush but then the plumber has said that won't work so don't know whose opinion to go with?! Thanks for the reply

 

[JohnD]

Assuming you have a fairly old boiler that does not have a pressure gauge

Go into the loft.

Look at the pipes

Under one of them you will find a small water tank, about 1ft x 1ft x 18 inches

I hope it has a lid

Inside will be a ballcock (float valve) like in an old WC cistern. Look at it. Is the water cold or hot? How deep is the water? How deep is the layer of rusty mud at the bottom? Is it brown? Is fungus floating on the surface? Do not stir it up.

Take some photos. Also of the filter. A chemical clean is so cheap that is always worth a try.

You will also need to locate the drain cock, around the lowest point in the system.

 

[ianmcd]

you can try it, but if there is a blockage , it wont work

 

[CBW]

Assuming you have a fairly old boiler that does not have a pressure gauge

Go into the loft.

She said a combi boiler, so doubtful it’s a cwsc if she’s correct. If it worked before, I’m struggling to understand why all of a sudden there’s a blockage.

 

[terryplumb]

Does the return pipe at the boiler get hot when heating is running and upstairs couple of radiators get hot ? It it doesn't there is no circulation and adding chemicals such as X400 is highly unlikely to work. I know the engineer said it doesn't ,but when was that and were upstairs rads hot ?

 

[Lottie77]

Does the return pipe at the boiler get hot when heating is running and upstairs couple of radiators get hot ? It it doesn't there is no circulation and adding chemicals such as X400 is highly unlikely to work. I know the engineer said it doesn't ,but when was that and were upstairs rads hot ?

Thanks for this - I think I will turn the heating on again for a good few hours and see if the pipes get hot so I've got a clearer picture.

 

[CBW]

Have you had any work carried out on the system?

 

[Lottie77]

Have you had any work carried out on the system?

No I haven't had anything done. I was assuming the sludge had just built up over time? Or does that not happen?