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steve1811 · Feb 11, 2013, 11:49 AM

Hi

We have 1 rad going through a 10mm pipe on our system, the other rad's are going through 15mm pipes. This one rad is cold from the bottom up, only the tip of the top is getting hot. Is there anything we can do? The plumber has suggested changing the pipes to 15mm?

massplumber2008 · Feb 11, 2013, 12:21 PM

Hi Steve...

Does this radiator have any kind of vent on it? If it does, then bleed the air out of the radiator... should resolve the issue!

If there is no vent on this radiator then let me know and I'll think on it a bit more, OK?

Mark

steve1811 · Feb 11, 2013, 01:34 PM

Hello Mark

Its one of those standard double radiators with a vent thing on the top.

There is no air whatsoever in the rad when you bleed it, just luke warm water.

My thoughts are that the water flows around the system really easily, but as this one is on a 10mm pipe the pressure required to pass through is greater, so it just bypasses the rad and goes where it's easier to flow into?

Is that viable?

massplumber2008 · Feb 11, 2013, 01:38 PM

If you have a monoflo piped system (loop system with diverter tees) then you should have equal delivery to the radiators.

I would try full out bleeding like a gallon of water out of the radiator... may have air stuck somewhere in the branch piping.

Finally, has this radiator ever gotten hot?

steve1811 · Feb 11, 2013, 01:54 PM

Oh I am not sure about that - it's a worcester bosch combi boiler that's all I know - and it's new

I have ensured the pressure is on 1.5

It only once got briefly hot when the plumber messed with the pipes and switched some others off by isolating them

He flicked/hit the two connector pipes as he said there may be an airlock

I may try bleeding the full thing like you said but its hard because of the water going everywhere :/

massplumber2008 · Feb 11, 2013, 04:56 PM

Pressure should be at 12-15 PSI...

Bleeding may be messy, but if you connect a small hose and direct the stream toward a bucket that should make it a little less messy! You would be amazed at how many radiators and baseboards I have had trouble with until I blasted the vent open wide and bled out those air pockets from the high spots!

I'm glad to keep working on it with you... just keep me posted as you go along. I answer every day but at different times.