New radiator added to system not getting hot

[Robthespoon]

Diy teething problems...

Hi, I added a new radiator to the system on the ground floor. I:
Drained the system
Cut into the hot and cold pipes running away from an existing rad
Connected them up to the new rad
Connected the new pipes back to the existing pipes under the floor

However, when turning the boiler back on (combi) the new rad, and one i took the feed from aren't getting hot at all, however the other 2 rads on the same floor (as well as the upstairs ones) are all working.

fyi there are no leaks at all, just 2 cold rads!

Any suggestions for the cause would be appreciated

 

[john90]

did you cut into the 22mm flow/return pipes or the 15mm pipes that go into the existing rads ?

did you turn on the rads valves both ends ?

did you bleed both rads so they are full of water ?

try to turn off all other rads, do both now get hot ? If so, probably needs a bit of balancing - you can find out about that on the faqs

 

[Robthespoon]

Hi John90

I cut into the flow/return pipes but they were 15mm not 22. All the underfloor pipework was 15mm.

And yes, both the valves at either end are on and they are both fully bled.

I will try what you suggested about turning off all the others, but suspect that as they are currently receiving no heat at all, that won't make a difference.

I do state for the record that I am a moderate noob : ) so look forward to any other ideas / suggestions if that is ineffective

Thanks

 

[denso13]

Turn off all the other radiators, including the ones which are working and getting hot.

 

[xr4x4]

Cut into the hot and cold pipes running away from an existing rad

I don't get this bit, hot and cold pipes? You mean the heating flow and return?

Connected the new pipes back to the existing pipes under the floor

I don't get this bit ethier, one of your tees off the heating flow and return should go to one side of the rad and the other tee to the other.

just 2 cold rads!

why two cold rads, I thought you only installed one?

 

[denso13]

However, when turning the boiler back on (combi) the new rad, and one i took the feed from aren't getting hot at all

 

[Robthespoon]

Hi, thanks for the replies

Still nothing. despite turning off all other rads.

By hot and cold pipes I mean flow and return,

And to elaborate, I teed off the flow and return, taken from either side of the existing rad, then took them off to the new rad, then connected them back to the system

And Paul, yes 2 cold rad despite only putting one new one on! That's the slightly baffling thing... Could it be an airblock/lock of some sort?

THanks

 

[xr4x4]

I still don't understand, why did you connect them back to the system?

You should only have one connection to the rad from the existing pipework.

Got any pictures?

 

[Robthespoon]

I'm out atm but I will take some photos tomorrow so hopefully it'll make more sense than my rubbish descriptions!

I really appreciate everyones help and suggestions so far

 

[Robthespoon]

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• Robthespoon
• 17 Sep 2013
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• Robthespoon
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Attached (hopefully) are pics of the pipework for existing radiator as well as sketch of how things are.

Hopefully it all makes sense. Have I done something fundamentally wrong with the way the pipes are?

To reiterate what I've said before, all other rads in house still get hot then heating is on. However the rad in the pics and new one do not at all, and in fact pipe A (on diagram) doesn't get hot at all

UNLESS... If I open tap B (which drains the water in the system to the outside) then the existing rad gets instantly hot! I don't know if the new one that I put on will as well because the system drains pretty quickly.

Any ideas as to why I am a muppet and it isn't working?

Thanks

 

[kbdiy]

If I understand your diagram you haven't teed into the flow and return, you have diverted the flow through the new rad so that and the old rad are now in series.

You should have teed the existing flow to one side of the rad, not removed any pipework, and teed the return to the other. No choice but to redo the pipework. You need the flow pipe to connect to the TRVs on both rads and the return to the lockshields.

 

[Robthespoon]

Hi KB, thanks for your reply.

Not sure I understand entirely what you mean.

Do you mean where I've drawn the dashes showing 'removed pipework' that should be put back in, with a tee put in it? and then a little further along another tee with the return coming back into it?

As it stands it seems that the flow pipe for the rad that was already there does into the lockshield and not the TRV. Does this change how I need to do things? If that makes sense........

I'm happy to redo but want to be sure so I don't balls it up again! : )

Is this diagram more what it should look like?

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• Robthespoon
• 17 Sep 2013
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[kbdiy]

Exactly as your new diagram shows, yes. The TRVs would normally be found on the flow pipes but it depends if they are bi-directional, in which case it matters less provided they are set up appropriately. One direction TRVs can cause problems if fitted on the incorrect side. Are they new, in which case almost certainly bi-directional and the fitting instructions will tell you how to set up?

Re-pipe to your new diagram and you should be good to go.

 

[Robthespoon]

The TRVs are relatively new, although I didn't put them on so don't have the fitting instructions. I'll redo the piping as per the diagram and hopefully it will work

Thanks for your advice