Re-plumbing System

[Dave-K]

My central heating packed up a week or so ago, and after inspection the pipes are choked with sludge and grit.

Ive tried cleaning the pipes out, i managed to get the system working again (including getting one radiator to work that hasnt wored for years) but it still takes a bloody long time to heat up. The pipes are all still very sludgy and i cant get rid of it.

Im planning on replacing the whole lot from the copper pipe after the motorised valve right round back to the copper again with plastic tubing. It is plastic that is on it atm so should be able to route it all easily enough.

Few questions

1: its 22mm and 10mm that is on atm, should i be swapping to 22 and 15mm to help stop the blocking?

2: the only plastic fittings i can find are push-fit, the ones on atm are threaded screw fixing (compression?) i would prefer to use the same type if anyone has any recommendations where to find them?

3: what is the deal with inserts? do they need to be put at all connections? im assuming they just make the ends more flush or something?

Cheers for your help chaps, much appreciated
Dave

 

[Fluffster]

If you are fixed in your mind to use plastic as I would prefer copper.
22mm with 15 mm pipes will increase your flow rate and is better than your 10mm which is more prone to blockages.
Use brass compression fittings to joint.
The inserts are very important as the prevent the plastic from being crushed by your fitting, of course it should always be cut clean and straight too.
Make sure you clean the system out afterwards either by chemical manual or powerflush.
Pete

 

[leakydave]

If the system is installed and treated properly 22mm and 10mm would still be ok. You would be better off adding a sludge remover and running that as much as you can to loose as much crap as you can and flush out with water before removing pipework. I hope you don't have white carpets!
Inserts are ESSENTIAL as they strengthen the pipe. You can use compression fittings on plastic using an ordinary olive, but don't forget the insert. You shouldn't use plastic within 1m of a boiler, but to be safe I go 3m. I hate seeing plastic pipe, so would come out of the floor in copper into radiators, but this will increase the number of joins, some of which will be hidden.
There may be a reason it has sludged up so much, possibly by a design fault... do you want to replicate this fault again in your new system? Better get it checked. Believe me, copper or plastic, a badly designed system will sludge up.
Are you ever likely to have mice in your house? No, not the family pet... never seen rodent damage on copper but they love plastic pipe. You have been warned!

 

[Dave-K]

Mice are very unlikely. never seen one in this area all my life hehe

The system is very old to be honest so is most likely just build up over time.

I really would prefer to use plastic as it will be quicker and there afew bends to overcome. will make my life easier

Are push-fit generally not as robust then? I use them all the time on air cylinders etc but when that leaks it doesnt really matter lol

 

[Fluffster]

Brass fittings are more robust than plastic for sure. If you are going for pushfit make sure you use the type that you push on then tighten the locking nut to secure as they are much better that the simple push and pull to lock ones.
P

 

[Fluffster]

Brass fittings are more robust than plastic for sure. If you are going for pushfit make sure you use the type that you push on then tighten the locking nut to secure as they are much better that the simple push and pull to lock ones.
P

 

[bengasman]

get the system powerflushed; quicker cheaper and better. replacing half the pipework will make precious little difference

 

[Dave-K]

im planning on replacing the entire pipework including valves etc and will clean out the radiators

is powerflushing still the better option?

replacing the pipework will cost around £200 all in for me to do it myself as i only have 6 radiators and its a ground floor flat

is powerflushing normally expensive yea?

 

[Dave-K]

when i say entire pipework i mean from about 1-2metres from the motorized valve where the copper changes to plastic on both flow and return

are the copper pipes likely to be full of crap aswell going to the boiler etc?

 

[Fluffster]

If you have sludge or magnetite in your system then it will have deposited it self all over your system, mainly resting in rads and where the flow is reduced so a powerflush would be ideal. Price well 10 rad system about £450 in London.
Pete

 

[Dave-K]

ok thanks ill try a poweflush first then, ive got the worst of the crap out now so that should fix it

cheers for the help guys!

 

[leakydave]

You might like to fit a magnaclean on the return leg of the heating pipework just before the boiler. This will attract black sludge and you can clean it periodically. Pay for itself in the long run...