some rediators not working on an unvented system

[beaumontnz]

hi

I have an unvented central heating system run by an ideal boiler.
It has the hot water tank with the expansion vessels etc,and was installed circa 2007.

Myself and a plumber have never seen anything like it so don t really know where to turn when we have a couple of rads that are not getting warm at all.Two downstairs and one upstairs.
The british gas guy said maybe a system flush,my plumber is not convinced.
The three rads in question are all full,but the sytem has not been used that much as the house has been empty for a year.Every time I have been or worked there I have run the heating for a short time and all the other rads come on straight away,apart from these 3.

Any pointers?

 

[muggles]

If your plumber doesn't understand the workings of this very common type of system, it's time to find a new one.

I assume you've checked the valves are open at both ends?

Try turning every single radiator off except one of the ones that isn't working, turn your heating on but make sure your hot water is off, and if possible turn the pump up to maximum. Does the radiator you've left turned on now get hot?

 

[beaumontnz]

valves open both ends.

no they do not.

 

[dilalio]

Remove the three rads and connect the valves of each together with a length of poly. If the heat doesn't transfer across then it's in the piping for those rads! You sure there's not an isolator/valve somewhere, that's been activated? Otherwise blocked or bad piping - water finds the path of least resistance!

 

[Nige F]

hi

I have an unvented central heating system run by an ideal boiler.
It has the hot water tank with the expansion vessels etc,and was installed circa 2007.

Myself and a plumber have never seen anything like it

Any pointers?

It is possible that you have a strange setup - I recall 3 in my working life - one was hidden air vents level with the top of floorboards- another was a hot cylinder cold feed to the top and hot out the bottom - and a large "blending valve" grafted into a domestic oil fired system , that did nothing except short circuit half the heating back to the boiler Pictures may help but of course most pipework is hidden.

 

[bernardgreen]

Maybe there are some isolation valves in the pipe runs. I was at a house over the weekend where the installer had fitted isolation valves on every spur from the flow and return pipes. The reason ( I assume ) was to isolate pipes that were run in places that were both unheated and would require carpets and flooring lifted to gain access to repair pipes damaged by frost.

 

[ServiceNumpty]

Hmm system fitted in 2007. TRV'S fitted. Hmm hammer and WD40 come to mind.

 

[oilboffin]

First thing make sure anyone working on the cylinder is qualified to work on it and I'd get a plumber who knows what he's doing cos the one you had seems lost on a common system.