Process of replacing all radiators

[Somethingsrotten]

We are planning to replace all our radiators (seven) and have a few questions:

Before doing so would it make sense to use Sentinel x400 or similar to clean out the system, and if so can we disconnect the old rads first so that the cleaner only goes around the pipes?

Also, is it advisable to use Sentinel x400 in old pipes? I have read that acidic cleaners can damage old pipes but this one is ph7...

Thanks in advance!

 

[dan2071]

If you remove the rads, it won't circulate around the pipework.

I wouldn't think twice about using x400

Dan

 

[baldykev]

HI
If you have a F/E tank make sure that is cleaned before draining down.

 

[Madrab]

If you remove the rads, it won't circulate around the pipework.

Depends, could be nice long 22mm flow and return main pipes with really short rad branches.

OP, if you are removing all the rads and draining down the system then I would suggest you'll get most of it anyway. Majority of the water is contained in the rads and any dirt in the pipes will be easily flushed out during draining, no harm in adding a cleaner though before the drain down and before flushing the pipework clean.

 

[dilalio]

You could remove the rads and temporarily join the valves with some plastic pipe - flush the system which will also include the rad feeds as the patch pipes will complete the circuit.

 

[dan2071]

Depends, could be nice long 22mm flow and return main pipes with really short rad branches.

You can’t circulate water down a pipe if there is nowhere for it to go. The Rads are the link between the flow and return.

 

[JohnD]

some radiator valves will fit the connectors on washing-machine filling hoses, so you can bridge or drain them. I have some for that, they are rated at 10bar cold and 3bar at 60C, which is probably adequate. the connectors also fit the mark 1 Magnaclean valves (the Mark 2 seems to have bigger connectors)

 

[Madrab]

You can’t circulate water down a pipe if there is nowhere for it to go. The Rads are the link between the flow and return

oops, misread the OP's post, though he was just removing some old rads

yup, a branch of the flow and return at the end of the run would be needed

 

[Somethingsrotten]

Thanks a lot all, that's really helpful!

 

[Somethingsrotten]

So, taking the advice here we removed the radiators and temporarily joined the valves with plastic pipe. When the drain is open and we turn on the water it runs through, however when we re-pressurise the system and add the cleaner, the water doesn't seem to be circulating through 3 of the 'radiators' (plastic pipes). Would this likely be caused by air getting trapped in the system? Obviously there's no way to bleed the air out of the pipes now...

 

[JohnD]

it needs balancing.

Shut the radiator valve on the "radiators" which have circulation, and it will be forced to go through the ones that haven't.

 

[Somethingsrotten]

Ahh of course, thanks!

 

[dilalio]

Ahh of course, thanks!

If no rads are in the circuit and just pipe is connected across valves, balancing is not likely to be necessary - but water does take the path of least resistance, so you may have to finesse! Use a connection on uppermost rad location to bleed any air by cracking open one of the pipe connections you’ve put in.