Quick question - new rad into old system

PardonTheWait · 21 Nov 2019 at 18:55

Hi all,

Just a quick one. We've got a mix of very old and reasonably new looking radiators in the house we've recently moved into.

One has sprung a small leak and wants replacing. We're also decorating a room and the rad is very old and tired so I want to replace, the plan really is to do each rad as we decorate each room.

The whole system is quite old - I had to drain and bleed it about a month and the water is quite black but I didn't see any proper sludginess.

We are going to get a new boiler hopefully some time in the next year and would get the system flushed etc when this is done.

Should I take any precautions to 'protect' the new radiators from the rest of the tired old system or is it not anything worth worrying about?

Thanks

Burned_Alive · 21 Nov 2019 at 20:55

I’d drain down and add some inhibitor when you top it back up

Simon42 · 21 Nov 2019 at 21:34

Protecting the new radiator and existing ones is just a matter of inhibitor if not already done as mentioned above. It can be added via a vent so no need to drain again.

The next step if you haven't already got a filter such as a MagnaClean would be to fit one as that will allow time for the filter to get the muck out of the system before a new boiler if fitted. Although the system can still be power flushed or similar before the new boiler install doing both gives the best chance of a clean system for the new boiler.

I added MagnaClean filters to my last couple of homes and it took a few months for them to make the water nearly clear again and they removed a scary amount of black gunk and small bits of debris.

PardonTheWait · 21 Nov 2019 at 22:11

The filter sounds like a good idea especially as this system has been a bit neglected I think.

I know it sounds like a silly question, I just didn’t want to fit a couple of rads only for them to get ruined.

cheers guys

Steampunk · 21 Nov 2019 at 23:58

I'd drain the system down, run some cleaner in it for a couple of weeks, then drain it and refill with some inhibitor. You don't really know if the system has been maintained by the previous owner, so if the water is black, there's probably gunk in the pipes and rads too.

Assuming you are going to take a radiator of water off the wall each time you decorate a room (ie lock the other radiators off and drain the pipes plus a rad), then at the end it's probably worth re-doing the inhibitor, as you'll be diluting the existing inhibitor each time you top up the system when you re-attach the radiator.

When you replace the boiler, get the installers to do a powerflush, and fit a magnaclean, then refill with an inhibitor again. Then don't mess with the water in the system.

DXP55 · 22 Nov 2019 at 15:33

+1 for a Magnaclean - they really do work.

PardonTheWait · 22 Nov 2019 at 23:13

Steampunk said:
I'd drain the system down, run some cleaner in it for a couple of weeks, then drain it and refill with some inhibitor. You don't really know if the system has been maintained by the previous owner, so if the water is black, there's probably gunk in the pipes and rads too.

Totally agree about the maintenance - I suspect it wasn't looked after that well. The boiler is ancient but I think has been regularly serviced, and the rads are a mix of older and newer, so I think they probably just replaced them as they gave up.

Got some cleaner and inhibitor today so once I get the rads fitted I'll do that. I've got one and I'll pick up the other next week as they're slightly odd sizes. The windows sills are really low in this house.

Hadn't heard of a magnaclean before this thread but they sound well worth it. When we get the boiler done we'll have one put in.

Steampunk · 22 Nov 2019 at 23:45

PardonTheWait said:
Totally agree about the maintenance - I suspect it wasn't looked after that well. The boiler is ancient but I think has been regularly serviced, and the rads are a mix of older and newer, so I think they probably just replaced them as they gave up.

Got some cleaner and inhibitor today so once I get the rads fitted I'll do that. I've got one and I'll pick up the other next week as they're slightly odd sizes. The windows sills are really low in this house.

Don't forget you actually have to run the system for the cleaner to work, so this is actually a good time of year. Just be careful when you're opening up drain screws or anything else that might break if you're the first person to disturb it in years. Make sure you know where your stopcocks are and that they work.

PardonTheWait said:
Hadn't heard of a magnaclean before this thread but they sound well worth it. When we get the boiler done we'll have one put in.

They are well worth it, but get one of the ones that are made of solid metal (bronze I think), not the ones made in plastic. Ironically, once you've got your system set up, and everything cleaned, the magnaclean shouldn't have much to do (especially with new rads), but they do grab anything that flakes off an old rad, and then it's just tiny particles. Mines been coming up clean for the last five or six years because I've always had inhibitor in since new rads and a boiler. Ideally it should be fitted just before the water circuit returns to the boiler, so anything that comes out of a radiator gets grabbed before it goes into the boiler. They are not difficult to fit or expensive to buy, so they are well worth it given the price of a boiler install.

PardonTheWait · 22 Nov 2019 at 23:50

I went to swivel one of the rads forward to strip wallpaper from behind and damaged the olive so I frantically had to sort all that out, we bled it all through after that so I know I can at least drain the system. We stopped it by lifting up the float though - I will nip outside and find out where the stopcock is though. There are several covers on the drive so I should really find out which one is the water!

adwol48 · 23 Nov 2019 at 03:06

i recently had to change a rad in the downstair toilet as the old rad was very corroded at the bottom, I just poured in some inhibitor into the rad before adding the blanking and vent plugs once it had been run to pass that inhibitor around i bleed it fully, had no issues so far but I will also be installing a magnaclean at some point to make dosing easier.