Vokera Linera 24, It's driving me mad, please help!

[cltheob135]

With the central heating turned off completely at the boiler, when I turn the domestic hot water on the rads heat up.
I have changed the Motorized Valve, three way valve overhaul kit,cleaned the three way valve cover and insured the pin is moving freely.
I've checked the motorized valve and it's operation seems fine.
Can anybody think of anything else it could be.

 

[archiedale]

New install ?

 

[cltheob135]

No, it's be commissioned for about eight years.

 

[aggis]

It's got to be getting thro' the 3 way valve. Check the cage you've fitted, [I've fit 1 then found the cage misshaped,] also are the washers fitted in the correct position. After try pushing the valve spindle with blunt s/driver then turn water on, see if flow gets hot, if it doesn't then check the motor head, try pushing in actuator with a screwdriver when dhw on, shouldn't move. Feel it'll be the Cage/service kit .

 

[Billy Bob Bob]

your plate heat is blocked its dumping down

It's got to be getting thro' the 3 way valve. Check the cage you've fitted, [I've fit 1 then found the cage misshaped,] also are the washers fitted in the correct position. After try pushing the valve spindle with blunt s/driver then turn water on, see if flow gets hot, if it doesn't then check the motor head, try pushing in actuator with a screwdriver when dhw on, shouldn't move. Feel it'll be the Cage/service kit .

good advice but...if its a blocked plate heat the diverter will dump down the flow

 

[aggis]

Always found when blocked plate heat exch, on Linea it shuts down burner & if you switch water of at that moment the boiler temp reads 92 C
Haven't had 1 dumping down flow.
If so hows it do it?

 

[cltheob135]

I'm going to give this a try, stand-by

Right, took the motorised valve off, pushed the shaft in fully, turned on the dhw and the rad still got hot. DAM whats the telling me???

 

[Billy Bob Bob]

Always found when blocked plate heat exch, on Linea it shuts down burner & if you switch water of at that moment the boiler temp reads 92 C
Haven't had 1 dumping down flow.
If so hows it do it?

all diverter valves regardless of boiler or valve make are designed as a fail safe to dump down result crap dhw and hot rads,a common fault on all makes of boiler,my own experience(and i am not being clever)is ignore fault codes and go with your knowledge,regardless of how complex a combi they all work and ultimately fail in the same way

 

[cltheob135]

How do I rectify this dump issue then?

 

[aggis]

I'm going to give this a try, stand-by

Right, took the motorised valve off, pushed the shaft in fully, turned on the dhw and the rad still got hot. DAM whats the telling me???

If you pushed the valve in, on the 3 way valve body, [not motor], & heating getting hot. Take the front section of valve off & check the washers & cage on the push rod [ Order a new 3 way valve service & change if not already done] This must be assemblied correctly, if in doubt check MI or on web at vokera [ there is a exploded diagram]
Think it's worth checking & even replacing the service kit the 1st as it's alot cheaper than changing the plate heat exch & flushing the system

all diverter valves regardless of boiler or valve make are designed as a fail safe to dump down result crap dhw and hot rads,a common fault on all makes of boiler,my own experience(and i am not being clever)is ignore fault codes and go with your knowledge,regardless of how complex a combi they all work and ultimately fail in the same way

I haven't heard of this before, I appreciate what you're saying , just asking question,as I believe we all live & learn all the time doing this job.
Cheers Aggis