Fitting New Radiator into Existing CH System

[toxictoad]

Hi all,

I'm going to be refitting my bathroom and also fit a new radiator into the existing sytem as there isn't currently a rad in the bathroom.

I've done some refitting/pipe work etc before so I'm ok with the general stuff but I've neve looked at fitting a brand new rad into a CH system.

If my understanding is correct, I will need to cut the 22mm pipe and add a connector 22-15mm then run the new pipe work into the bathroom. Is this correct? Are there any important things I need to know before starting this job?

Thanks
toad

 

[D_Hailsham]

If my understanding is correct, I will need to cut the 22mm pipe and add a connector 22-15mm then run the new pipe work into the bathroom.

There should be two 22mm pipes, one is the feed from the boiler, the other the return to the boiler. You have to take a tee of both of them, one to each side of the radiator. Make sure you are teeing into the feed after the pump.

If you have a F/E tank in the loft, clear out all the gunge in the tank before you start. A bucket, sponge, jam jar and trowel are useful.

Drain down.
Fit new rad.
Flush through with cold water.
Refill.
Bleed all rads.
Balance the system.
Add Sentinel X100 inhibitor (and X200 if you live in a hard water area)

If you have the time it would be a good idea to add Sentinel X400 cleaner and let it circulate for a week or two before you drain down. Though that might not be so easy now the weather is warming up.

 

[toxictoad]

Hey thanks for the reply, I totally forgot about it coz other things came up but now I'm close to doing the job and have a couple of questions.

The system only has a combi boiler so I guess this makes the job easier.

What do you mean by "Make sure you are teeing into the feed after the pump" Or doesn't this matter for a combi boiler?

Does the feed from the boiler have to go to the Left or Right of the Rad or doesn't it matter?

Thanks again

 

[izzy eckerslike]

What do you mean by "Make sure you are teeing into the feed after the pump" Or doesn't this matter for a combi boiler?

Does the feed from the boiler have to go to the Left or Right of the Rad or doesn't it matter?

Thanks again

I made the mistake of adding a new rad on a stretch of pipe below the pump so it made the rad pull in water from the return & push it back into the flow.

Before the pump water is being pulled but after the pump it is being pushed so it needs to push the hot flow into the rad.
a lesson I have now learned, if your pump is in the boiler then I would think you would be o.k regardless

 

[bengasman]

With any boiler that has the pump inside it, you can tee off pretty much where you want. Flow left or right makes no difference; take whatever is easy to route the pipes. Ideally the operating valve, especially a trv, goes on the flow side, but in most cases not really important. Most trv's are bidirectional these days, though some react slightly differently if installed on the return.

 

[toxictoad]

Thanks guys, I can't see any kind or pump or anything other than the water fliter (hard water area) and the pipes going in and out of the boiler so will asssume for now that the pump is inside. Will get the make n model tomorrow and make sure if I can.

 

[toxictoad]

Hey all, I started to try and suss out the job of fitting this new rad today and I looked everywhere for the drainage point but there doesn't seem to be one!? Is this possible?

I've looked at two other CH systems, one has the drainage point off the 15mm pipe that connects to a downstairs rad and the other has the pipe going outsite the house through the air vent.

The house that wants the new rad is different in another way also. The 22mm runs out the boiler, then connects to 15mm pipes that run round the house but the pipes that connect to the valves are smaller, I'm assuming 10mm but didn't have a rule to check.

Any advice?

Thanks

 

[david17uk]

If it's microbore to the rads, the manifold is usually 22mm. How many rads are there all together, being fed from the 15mm pipe?

 

[toxictoad]

If it's microbore to the rads, the manifold is usually 22mm. How many rads are there all together, being fed from the 15mm pipe?

There are 5 rads in total, one in the back bedroom which is where the boiler is also, then one on the oposite wall in the front bedroom then downstairs there's one in the back room and one in the front. All these come from the 15mm to 'microbore'? but there's also one in the hall and the pipes to this are the microbore (if that's right?) and those pipes come from upstairs.

The rads were fitted about 10 years ago.

I just assumed (bad move) that the system would have a point somewhere downstairs to drain it.

Would any of this make any difference to draining it? There has to be a way of draining the sytem right? But does that also mean that some systems won't let you fit a new rad?

Thanks

 

[david17uk]

Some systems don't have a drain off valve.

The best way would to be to remove a rad downstairs, closest to the door. (don't forget to turn the valves off, each side).

Then get someone to help lift it off, with your fingers over the ends to stop the water coming out.

Once the rad's out, stick a short length of 15mm copper into the end of your hose - then use a nut and olive on the other end of the copper to attach it to one of the rad valves. Open the valve and this will drop the pressure off your system.

Open the air vents on the upstairs rads and the upstairs will empty. This should be sufficient to fit your new rad (if it's going upstairs)

 

[toxictoad]

oh that sucks!
new carpets in both downstairs rooms...it sounds like a disaster waiting to happen ;o) but I guess with the right floor covering etc all messes could be avoided.
Thanks for the advice I'll have to see what they wanna do

 

[izzy eckerslike]

Replace that radiator tap with one with a combined drain tap to make it easier for future drain downs

 

[toxictoad]

Hey,

I got the pipe work in and so far so good but didn't drain the system down as such. What I did was this.

1. Turned the Boiler off
2. Bled the rad in the same room as the boiler until the pressure was at 0
3. Cut the two 22mm Pipes that come from the boiler just before they go under the floor boards. There was just a little water that came out the pipes but just a couple of cups.
4. Fitted 22mm - 15mm T Piece join and put in the new pipe work through the wall into the bathroom and put temp end caps on both pipes.
5. Turned on the boiler and built up the pressure to what it was before

I'm unable to test the CH atm coz we're waiting for the plasterer to do his job on Monday but I can't see any issues so far and there's hot water )

Just hope that when the rad goes in everything will still be good!

 

[dextrous]

No problem so far then. Think I'd still advise getting a drain-off point installed somewhere downstairs, especially for flushing out the pipework or other maintenance at some later date. In the meantime, next time you have to drain the system in readiness for connecting to the new rad, it's worth sticking a hose on one of the tails using one of a variety of methods (whilst the other still has the cap on) and flushing any obvious sludge out by using the mains feed from the combi filler loop. Then do the same with the other tail for a bit of reverse flush.

When you've hung the rad, pour some inhibitor into the system - easiest way is to remove the bleed plug (the whole of the chrome bit, not just the little square nipple) and use a funnel to help pour it in. Then pressurise and away you go

 

[Goldspoon]

If one is ever fitting an upstairs rad and there are no drain valves downstairs then it is very simple to drain down: stick an iso in the top of a downstairs rad.

Pick a downstairs rad.
Close the two valves on the rad to isolate it.
Bleed the rad (will only bleed a short period whilst pressure in rad drops).
Take off the bleed valve with a spanner.
Into same hole screw a 15mm iso valve with some PTFE on the thread and some 15mm copper sticking out the other end.
Attach hose to 15mm.
Open rad valves.
House will drain to level of where you are working (upstairs will drain).

I first did this when I went to a hotel with 35 rads and none had drain points.