Central heating - mailfunction

[capri579]

Can anyone please help with my conventional C/heating system approx 20/30 yrs old. Boiler make Potterton NetaHeat 10 - 16.
The problem i have is i can not have just have the hot water on without the c/heating being on. i have turned off all the valves on the raditors in the short term. i can not locate and 2/3 way solenoid/servo motor actuated valves any where on the system. Any suggestions welcomed
thanks
capri

 

[seco services]

i would say your system is gravity hw pumped heating.
what programmer have you ?
can you not just switch hw on only heating off ?
or can you select hw only but rads still get hot ?

 

[twgas]

check f&e tank has water in it - couple of inches above cold feed connection is about right.

 

[capri579]

Yes system is gravity feed. Programme is Danfoss 3060 i replaced it Dec'08. it is set for Heating off , Water on twice but as u said heating still comes on.

 

[seco services]

has the system got gravity check valve near the pump ?
will be stuck open.

 

[capri579]

I have just checked the water level in t expansion tank and it was approx 1 inch below the water stain mark in the tank so i have brought it up to the water mark on the tank.

The pump is located below the boiler. one side of the pump is connected to the boiler and there is no valve between the pump and boiler. T other side pipe goes straight up to the first floor ( boiler located on wall in kitchen) i can not c a valve, pipe is concealed.
How big is the check valve

 

[seco services]

approx 2" long

 

[capri579]

Sorry i have had a good look above and below the boiler as pipe from the pump is routed behind the boiler but no sign of the valve.

 

[Nige F]

I have just checked the water level in t expansion tank and it was approx 1 inch below the water stain mark in the tank so i have brought it up to the water mark on the tank.

The pump is located below the boiler. one side of the pump is connected to the boiler and there is no valve between the pump and boiler. T other side pipe goes straight up to the first floor ( boiler located on wall in kitchen) i can not c a valve, pipe is concealed.

So there are only 2 pipes connected to the boiler ? . To have a gravity circuit for domestic hot water there would be 4 pipes- 2 for grav. circuit and 2 for pumped heating

 

[capri579]

Nige F
I have had another look and there are another 2 pipes connected to the top rear of the boiler as well, still no sign of check valve.

 

[seco services]

probably under the floor upstairs.

 

[capri579]

Ok that is going to be serious as i have re furbished the bathroom, new floor tiles etc. could there be another reason?

 

[seco services]

have you any pics of you boiler set up ?

 

[Agile]

probably under the floor upstairs.

I thought they were only recommended to be used vertically or was that just good practice?

Tony

 

[seco services]

you could have a point.
as all the ones i've know to jam have been fitted horizontal.