Radiators stil get hot when only 'Hot water' is selected.

[Golaboots888]

Hello.

My radiators (up and downstaris) still get hot even though I have now got 'Central heating' permanantly off on teh heating controller, leaving hot water to come on twice a day.

I can see what I beleive to be the Motor Operated valve moving position but am not sure.

What are likely causes (besides misidentification of parts!) and what should I do?

Below is a photo of the side of the cylinder with the MOV and other parts on it. Could anyone identify each numbered bit and what it is for?
I know 1 is the MOV and the black lever on the side an indicator for showing it is actually moving.

I know the grundfoss pump is for pumping the water around the radiators too but am unsure what the other bits are.

 

[kevplumb]

View media item 11360

 

[Golaboots888]

What is the purpose of the bypass?

 

[kevplumb]

to keep a minimum amount of water flowing through the boiler

 

[Golaboots888]

Any ideas on the hot radiators front?

 

[gas4you]

3 port valve stuck in mid position

 

[namsag]

Has it always done this or just started.

 

[Golaboots888]

Has it always done this or just started.

It has done it for ages (end of last summer) I had just turned the rad valves off at the time. Over winter it was no problem (rads on more than water anyway) so I forgot about it.

I've turned the rad valves off again now we dont need the heating but it cant be ideal.

 

[seco services]

is pipe no 3 hot when only the hw on ?

 

[Golaboots888]

is pipe no 3 hot when only the hw on ?

Pipe 3 gets warm near the value but it cool further down when only the HW is on.

Pipe 2 is roasting hot and for some reason the pump sounds like it is running.

 

[seco services]

pipe 2 is the main flow from boiler and if hw is calling the pump will be running.

 

[seco services]

you'll need to check the bottom pipe where 4 joins.
there should be a connection from the bottom of cylinder that joins it, that will be hot.
but follow the pipe further back it probably gos into the floor is that hot ?

 

[Golaboots888]

I'm confused. Does the fact that pipe 3 staying cool mean the valve is working? What other cause could there be for hot rads?

If the HW and Heating are on which pipes should be hot? the pump should run.

If HW only which pipes should be hot? Why does the pump run? Is it just pumping water between boiler and cylinder?

If CH only which piples should be hot? The pump is then pumping the hot water through all the rads in the house (if they were turned on)

 

[seco services]

if the outlet from valve to heating is warm going cold further down then the valve is fully shut to heating. working ok.

the pump will run with what ever is calling hw or heating. its a fully pumped system.

hw only will pump yes boiler round to cylinder and back again.

that pipe at the bottom where 4 joins we need to look at.

wheres the pipe go when it comes round the front of the cylinder ?

 

[Golaboots888]

I'm not sure 4 does join it.
Here is another pic.