Central heating / hot water problem

[Jimbo78]

Hi all, been trying to solve a problem with my mum's CH/HW system and I could use a little advice.

The problem is, the timer which is a seemingly very basic Wickes rwb7.cw only allows heating and water to be on together (the original programmer landis & gyr rwb200 had them seperate) - and they only go off when the mains switch next to the programmer is used to cut the power. The boiler seems to be on almost constantly, only stopping for a few seconds before firing up again. The end result is the hot water gets far too hot (to quote it's 'jumping out of the tap')

I have replaced the mid position valve with a Drayton MAI/679-3 but this doesn't seem to have helped, the W,M,H lever stays on 'M' and the manual lever is firmly in place pushed in to the right - is this meant to be released with a little force?

Would replacing the Wickes timer help (it actually states in the instructions, not suitable for replacing the rwb200 as you are replacing a timer with a programmer but it was anyway... 😵) or could there possibly be a thermostat fault?

Many thanks for any help.

 

[king of pipes]

Electrician needed but yes a two channel programmer is needed . kop

 

[A Plum]

When you say you've replaced the mid position valve, do you mean just the valve body or both the valve and the motor (head)?
Either way, you need to be able to operate them separately and so logic would naturally suggest, you need a H/W and Heating programmer.
Depending on how it's all wired up (sounds like it may have been DIY'd ), your room stat could be demanding heat once you've switched off the 'wickes device'.
Normally, once you isolate the boiler, the programmer should isolate also and vice versa, unless it's a wireless programmer/stat.
Either way, we could speculate all day long. You need an electrician or a heating engineer/experienced GSE.

 

[spanner]

Need a two chann programmer and maybe a few extra wires