Thanks for the swift replies Gents. I have the in-laws coming to dog sit next week while we're away. I'll be in for an ear bending if we get a cold spell!? (Keep the bills low though!!!!)
I spoke with HCS and their techy guy is mailing me the electrical test sheet, to ensure it is the valve and not the controller. He didn't raise any box replacement theory. He just stressed that "they are different now..." an highlighted the benefits of the changes allowing future repairs/replacements to be completed more easily. Guess i'll have to wait another 19 years to find out if that's true - or will they change it agin in the name of progress??? What or who is going to do the test procedure - i'm not sure yet - but at leats it's a step in the right direction.
My system has no room stat. The rads were fitted with stats but i have removed most because of problems with poor circulation from my trustee old Potterton Flamingo (Circa 1991).
Roger, Thankyou for the offer of a phone call. You will see by the time I posted this message, that a call now would probably result in some harsh language. However, if I get time before work tomorrow- i'll certainly give you a bell.
I have removed the actuator cover and the motorised cog. I've then pushed the metal lever to water only and it stays put. The black plastic clip is broken, so i'm now thinking if it is spring loaded, it should return?? I think I read earlier about a dose of WD40 to free the mechanism inside the 22mm junction (3 way), which could therefore be seized if the spring loading is ineffective or broken off.
I'm nearing the point of just chucking in the £70 replacement fee and going for 'drain down'...unbolting and swapping the lot in the hope it works. Sods (or Murphys) law says however, that something will go amiss and there'll be no heating at all - so i'm tempted to do nothing until back from hols.
(PS I've just taken a break and viewed my e-bay in box, re: item number 230282352908 - which is a replacement actuator box. The vendor states 'yes they do clip on' He then states he sells the 22mm junction too if I need one - but it will need a drain down of course...which sounds to me like he means the box
will swap with the old one? I have sent him another question of course)