To replace all central heating pipes or not

Legacy_user

I've got an empty house that is going to be rented out and whilst it's empty the lead pipes have been taken out

The radiators are all going to be replaced and it looks as though the original copper pipework is at least 20/30 years old although it's difficult to be certain.

Whilst the house is empty and some floorboards are up in many of the rooms would it be wise to redo all of the central heating pipework? I was told that in all it would probably add only a few days to the overall labour cost.

Any thoughts would be welcome.

nofoollikeold

1. If the existing pipework is imperial (1/2" and 3/4") I'd replace it with new metric pipework (15 and 22mm) . Otherwise fitting the new radiators may require imperial / metric adaptors to be fitted.
2. If the existing pipework is metric. Then:
2a. Try and see if it is clear inside. Perhaps cut out a piece from a horizontal run, one upstairs, one downstairs. If clear (may have a very thin deposit around the inside walls) then no point in replacing it.
2b. If not clear, why take the risk of partial blockages becoming full blockages - replace.

If it were me I'd replace it all with copper with soldered or press fit joints, not push fir or compression joints. I think soldered has the edge as modification (e.g. adding a radiator) doesn't run the risk of soldering near a fitting with a rubber O ring in it.

If you are having a new boiler fitted, make sure a filter is fitted on the return pipe to the boiler as close to the boiler as possible, and make sure the system has inhibitor added. Then new pipes, new radiators and a filter will make it more difficult for the boiler manufacturer to void their guarantee.

Johnhowell

Some personal recommendations/suggestions:

Do not fit plastic pipes.

I would recommend if you have access under the floor boards to isolate the pipes from the wood joist (fluffy or copper slip) stops them clicking when expanding and contracting - I wish I could lift all the floor sheets here to get at some annoying noisy locations.

If fitting a new boiler - most seem to require a "powerflush" for warrantee purposes so old sludge stuff does not "clog" the new boiler. generally not the other way around. If keeping the old boiler - could have the exchange removed, cleaned and checked. The plumbers visiting here said the exchange will be clogged but on examination the 20+ year old Gloworm was spotless.

Also, I recommend fitting a magnaclean to see the stuff that does get generated by the system over time.

All the best and good luck.

bris

Plastic pipes are now the installers choice, copper is unnecessary now.


Todays push fit fittings are excellent and the plastic is flexible so can be manipulated without a lot of joins, especially as copper is restricted to 3 meter runs.


Don't be put off by plastic.


How ever if you have perfectly good cooper down then leave it where it is, 30 year old copper is better than the stuff you get today.

Gloomendoom

nofoollikeold wrote: »

1. If the existing pipework is imperial (1/2" and 3/4") I'd replace it with new metric pipework (15 and 22mm) . Otherwise fitting the new radiators may require imperial / metric adaptors to be fitted.

Can you actually get 15mm to 1/2" adapters?

FreeBear

Gloomendoom wrote: »

Can you actually get 15mm to 1/2" adapters?

Not needed. Imperial copper pipe is as near as damit the same size as metric 15mm copper on the outside diameter.

3/4" and 22mm pipe, you do need an adapter or use 3/4" olives with a compression fitting (one can bodge a 22mm olive to fit though).

Gloomendoom

FreeBear wrote: »

Not needed. Imperial copper pipe is as near as damit the same size as metric 15mm copper on the outside diameter.

3/4" and 22mm pipe, you do need an adapter or use 3/4" olives with a compression fitting (one can bodge a 22mm olive to fit though).

That's what I thought. I have a mix in my house and haven't had any problems getting modern radiators (or anything else) to fit and seal properly.

System

I've read up on the plastic vs copper debate and I reckon there's pros and cons to both but as a general rule of thumb I'd probably go with copper although I've been told that many new builds have got plastic

Alex1983

I'd go copper where ever possible, plastic has a horrible habit of creating metal flakes of sludge, that look like tea leafs which cause full flow blockages.

System

Hi Alex, I'd not heard about the metal flakes of sludge situation. Is the metal flakes something that happens quite a bit here in the UK? Definitely I know it's best to have copper in rural locations due to mice and rats nibbling through the material

The copper vs plastic piping debate is still going strong

https://www.diynot.com/diy/threads/is-uk-polyb-pipe-the-same-as-the-stuff-condemned-in-the-us.256888/

Alex1983

Don't know the science behind it but the dirt sticks to the pipe the same as it would do in copper but in plastic it breaks off in to bits like tea leafs and then will block at a elbow somewhere.

If your going with plastic make sure the system is clean and kept dosed with the correct chemicals.