one out of of 4 radiators not heating...help please.

[robturpin]

Hi,

This is what my current situation is.

I have a 2 floor flat, Kitchen Bathroom and Living room on one floor and then above it my bedroom on the same floor plan as the living room. I have a Ideal Classic LXFF 230 Combi Boiler that supplies 4 radiators. one in each room. My bedroom radiator has never put out enough heat to fill the room (it was a designer radiator prolly not that efficient) so I replaced it today, with kudox double panel 7350btu drained the system fitted it in a different position and bled the system. Started it all back up and the 3 radiators down stairs get nice and hot but the bedroom stays stone cold all the way down to where the pipe enters the floor.

When I close all the other radiators off (ie at the theromstatic valve) the boiler shuts off and won't ignite. (as if in a safety shut off mode) When I open the other thermostatic valves it reignites and continues to heat the 3 downstairs rooms.



I hope this is clear and helps you give me advice...many thanks to all

Rob

 

[robturpin]

Oh and the boiler is in the kitchen on the 1st floor with the tank above it in a loft space.

Rob

 

[MANDATE]

Sounds as though one of the radiator valves is closed.
You could try bleeding the radiator with one valve closed and one open, then reverse the situation. You should get water out in both cases, but if not the valve you think is open may well be closed.
When you changed the radiator, it would have been the ideal time to open each valve to ensure there was no problem


Other than that it might be a balancing problem, The pipes to the problem radiator may offer resistance and the water will take the easier route through the other radiators. Because the radiators have TRVs they may not have been balanced.

 

[robturpin]

Thank Mandate, I have bled and opened each radiator in turn from the closest to the boiler to the newest one. All the valves are fully open and the radiators are showing a 12deg difference between the inlet and outlet valve so i think the balancing is fine apart from the new one which is stone cold.

If I close off all the valves on the 3 radiators downstairs it essentially means the new radiator is the only one in the system....and it still doesnt heat up and the pilot light won't stay on in this circumstance, all the others need to be open for the boiler to work?

 

[darren17]

shut off the rads downstairs on both sides
switch the new rad on with both valves and bleed as you still have air in the system
otherwise you can crack the nut on the flow pipe and the pump will force the air out

 

[darren17]

if you have 4 rad's with 4 trv's fitted you should have an a/b on the system

 

[robturpin]

Thats what I thought so I spent an hr earlier doing that. But it was just a constant flow of liquid out of the bleed valve and no air came out. where could the air be??

um sorry for the ignorance but what is an a/b?

 

[darren17]

an a/b is an automatic bypass it sounds like you don't have one
if you don't have an a/b you will have to fit a manual valve to the new rad
this is why your boiler is shutting down

 

[robturpin]

I don't know, I certainly haven't fitted one...what's the purpose of it? what will it achieve?

 

[darren17]

it will allow the water to circulate if the trv's have shut down.
the old rad that you removed did that have a trv on it??
that would mean that if before you removed the old rad the system was working ok with 4 trv's then that tell's me there is a a/b fitted
if that's the case then switch off the 3 bottom rads allow the top new rad to heat as you say that it is full of water and then just balance the system

 

[robturpin]

Hi. Thanks for your reply. Yeh it did have trv on the old one and it worked albeit not very well (hence the replacement). That's what I've already done, I shut the 3 off downstairs so that the boiler would jst heat the one upstairs but for some reason in this scenario the boiler will not ignite (as if in a safety mode) the pilot light will come on then extinguish after 5-10 seconds. It's not till I open up the others that the boiler returns to working correctly. I think I'm going to hve to get n engineer to look at it!

 

[hammerswinger]

Hi,
Have you checked the pipework that you altered to the new rad, you have got a flow & return, & not 2 flows or returns!

If all is well with the alterations you need to find out if the pipes to the new rad are flowing freely, to do this you will have to drain down & remove the rad.
Then open each valve in turn, have something to catch the water in, if the water flows freely from each valve you then know for sure that the flow & return aren't blocked.

Make sure the CH pressure is ok (1.5 bar cold) before testing the flow from the valves.


Cheers.

 

[darren17]

when you refilled the system did you not check that it was repressurised ??[/img]

 

[robturpin]

Um no. Could this be the issue? How do I go about repressurising it? I assumed that once the water had filled all the radiators that that was sufficient?

 

[darren17]

yes this is the likely problem !!!
there should be a filing loop somewhere about the boiler !!!
but as this is a sealed system run by gas you legally need an rgi tech if the filling loop connection's are not outside of the boiler housing.