New Radiator Cold (I've read the FAQ)

[OscarFoxtrot]

Hello,

Fitted a new radiator and cannot get it to heat. I've ran through all the checks I can think of but so far no joy.

New TRV is fitted to flow side (tho it is bi-directional). I've tried both directions just to be sure. Bleed valve is on opposite side to TRV
New lock shield on return side.

I shut off all the other radiators, drained the system, fitted the new radiator and valves, opened TRV to fill new rad then bled it before opening lock shield. Opened all the other radiators as before then fired up boiler again.

All other radiators heat up well as before but the new radiator won't heat. the TRV and pipe work up to it get hot but the radiator does not.
I've removed the valves from the radiator and tried the bucket test and the flow was good from both.

Its a 28kw condensing combi supplying 6 radiators. The new radiator is a tall flat panel type.

Hopefully I've missed something simple.

Any advice appreciated.

 

[JohnD]

did it warm up when you turned off all the hot ones?

do both the flow and return pipes on the rad warm up? What are they connected to?

What do you mean when you say "tall?"

It's panel not column? So it probably isn't upside down.

 

[OscarFoxtrot]

Hi John,

Forgot to mention, no it didn't warm up when I shut off all the other rads

Only the flow side gets hot. I assume they are connected to the main flow and return lines. Its the same tails that supplied the old radiator (altered to suit new rad)

Sorry not sure why I put panel Its a column ( http://www.mrcentralheating.co.uk/revive-2000h-x-490w-three-column-vertical-radiator )

Definitely not upside down

 

[JohnD]

how do you know?

(seriously)

 

[OscarFoxtrot]

There is only one option for the bleed valve hence that's the top. The other side is sealed.

 

[Terry lambert]

Shut both valves, put in a 1/2 inch male iron to compression in place of the bleed vent with a bit of copper

Attach a hose to copper and run to drain, open one valve, shut, then the other.

Should tell you where the problem is, or shift a blockage

Was there a blank in the end that you accidentally pushed in instead of taking out?

 

[OscarFoxtrot]

Hi Terry.

Not that I remember but I was thinking maybe something was causing a blockage inside the rad itself although when I drained down the rad it seemed to flow out freely.

I'll see if I can bleed the rad to a drain like you suggest.

Cheers

 

[OscarFoxtrot]

I had another look at this last week and again had no joy.

Fitted a 1/2" to compression fitting and ran to drain. Got good pressure and consistent water flow from both the flow and return side independently.

I then stripped all fittings from the radiator to see if the was something causing a blockage but never say anything untoward.
One thing I did notice was that on the flow side at the bottom the first anfd second column are blocked. I guess this is just to force the water up the radiator as it first enters?

Next up I simply fitted a short piece of pipe between the valves (in place of the radiator). Opened TRV and lock shield but the pipe never got hot at all yet when I ran each side on their own, into a bucket, the pressure was good and the water was very hot.

I did all these tests with all other radiators and valves shut off then repeated all the tests with the valves open as they would normally be. Made no difference, I cannot get any heat through the new radiator.

There is a hardwood floor down making it difficult (last resort) to trace the pipe work.

Its almost as if there is equal pressure working against itself from both sides. Is this possible? say for example both pipes were in actual fact connected to the flow by mistake, would this happen?

As always any help appreciated

 

[45yearsagasman]

As always any help appreciated

I haven't read the whole saga, but did the original rad work, or is this a new rad that you've connected to the system?

 

[OscarFoxtrot]

As always any help appreciated

I haven't read the whole saga, but did the original rad work, or is this a new rad that you've connected to the system?

I'm told the old rad worked but I made the mistake of not checking before I removed it (it was off for a while while the room was plastered then decorated)

 

[45yearsagasman]

Is this a bathroom rad?

 

[OscarFoxtrot]

Nope, its in a hall.

 

[MeldrewsMate]

...It's almost as if there is equal pressure working against itself from both sides. Is this possible? say for example both pipes were in actual fact connected to the flow by mistake, would this happen?

Unfortunately, yes
As you have no evidence that the old rad worked, plus the test with the pipe between Flow & Return didn't achieve a flow, then I have to conclude that there is little or no pressure difference between flow & return connections.

Sorry to say you mayend up lifting the floor.

 

[OscarFoxtrot]

...It's almost as if there is equal pressure working against itself from both sides. Is this possible? say for example both pipes were in actual fact connected to the flow by mistake, would this happen?

Unfortunately, yes
As you have no evidence that the old rad worked, plus the test with the pipe between Flow & Return didn't achieve a flow, then I have to conclude that there is little or no pressure difference between flow & return connections.

Sorry to say you mayend up lifting the floor.

Makes sense MeldrewsMate, thanks for the reply.

Looks like I'll need to chase these pipes somehow