potterton kingfisher mf will not run

[markthesparky]

Hi wonder if anybody can help ?
I have a kingfisher mf rsl 50 it will not run for long on, demand from the programmer the boiler fires up but soon the flame goes out.
10 mins later the boiler fires up again and so on untill programmer turns off.
please help
regards mark

 

[seco services]

is the pump running ? pump may of failed so boiler overheating

 

[markthesparky]

Hi the boiler is gravity hw and pumped heating so does the pump need to run? if it does it may be air locked as i changed a rad and valves last week but it worked fine till last night.

 

[seco services]

pump needs to run if on heating.

 

[markthesparky]

sorry should of explained myself better the boiler is only on hot water at the moment

 

[seco services]

are you getting hw ?
is the flow/return pipework on the cylinder getting hot.
as the coil could be airlocked and restricting the flow of water

 

[markthesparky]

pipe from boiler is hot but top and bottom of the tank are cold

 

[seco services]

sounds like an airlocked coil to me.
have you any bleed valves on the pipework to the cylinder ?

you have checked the two pipes that enter the side of the cylinder ? they are both cold

 

[markthesparky]

yes the two pipes on the cylinder are cold
Why would an air lock develop?
have I a leak
I dont think i have a heat coil on my tank there is only the 2 pipes on the tank

 

[seco services]

you should have a pipe from the centre top.
a pipe into the bottom
and two pipes into the side about half way up.

 

[markthesparky]

just checked the tank one pipe at the top and one at the bottom
then the instalation manual and the system seams to be an open vented gravity hot water and pumped central heating system
I dont have a divertor valve and no heat coil so am very confused

 

[seco services]

how many tanks have you in the loft ?
have you any label on the cylinder? saying primatic.

 

[markthesparky]

two tanks in loft heating top up tank and hot water topup tank water tank.
the tank label says vented hot water cylinder

 

[seco services]

indirect cylinder.

you have a coil then in the cylinder.
even with the hw being gravity, no motorised valves etc it still has a coil.
its not primatic you have to tanks.

so feel round the back where ever you have two pipes going into the side some where.
in total it should have 4 pipes.

 

[paulybaby]

select c/h. turn up room stat. does boiler stay on till rads hot?