Help really needed. No hot water but hot radiators??

[seve6526]

Hi, really appreciate some help. Ive got a potterton central heating system with a hot water tank in airing cupboard and a cold tank in the loft. The central heating works fine but there is never any hot water.

Ive looked in a DIY manual and checked the motorised valve. Even when i turn on the hot water on the timer panel it doesn't illuminate the D.H.W light but does the CH light? The motorised valve is always warm to touch and feels like its vibrating all the time.

I've taken it off the valve and the little brass nipple turns all the way around quite easily. Also the manual select on the base of the motorised valve doesn't do anything.

Just wondering if i should replace the motorised valve, a myson or whether its the timer panel not selecting the hot water. Am very confused.

Any advice / help is very gratefully recieved. Many thanks

 

[tryitandsee]

Have you got the hot water cylinder thermostat turned up (working).

 

[spraggo]

Have you got the hot water cylinder thermostat turned up (working).

Have you checked to see if there is water in your small header tank.

spraggo

 

[45yearsagasman]

How many motorised valves have you got? 1 x 3 port or 2 x 2 ports? and what make?Soun like Potterton/Myson

 

[seve6526]

Ahh thanks for helping, yeah definately got water in the cold header tank. Its a single motorised valve, a myson mpe322. Its a 3 way, has 3 pipes out of the valve. Its always warm to touch. The thermostat on the tank is turned up and when i put the immersion heater on the water is hot.

I tried taking the valve off and turning it with a screwdriver when electrics were off but no luck.

When i put hot water on, the boiler fires up, the dhw light on the valve doesnt light up but the ch does and the radiators get hot??

Are guys as good with chics are u are central heating cos both semm impossible to understand to me!!!

 

[Hugh Jaleak]

Need to check if the valve is recieving power from the cylinder thermostat. If you are confident with using a multimeter you can do some checks.