Drayton Mid-Position Valve and CH system

[iwilliams]

I recently had problems with the motorised valve and the manual lever on the actuator was not moving when I turned on HW, CH or both. I subsequently bought an actuator and after wiring it up electrically, the manual lever moves correspondingly but as soon as it is fitted onto the valve head, it gets stuck. I applied some 3-in-1 onto the valve spindle and it's working better now but is this a sign that I might need to change the whole thing soon?

On a side note, my pump feels very very hot shortly after CH is on, is this starting to go as well? My boiler is over 25 years old now so I guess this is to be expected, haven't had it serviced for 7 years and still no problems with it really. Do you think I should think about draining my CH system soon as I'm guessing a lot of sludge has built up over the years. Is it true that for a system this old, it's not advisable to add any inhibitors or cleaners, and you’ll likely get leaks from the radiators?

Lastly, I've noticed that in the airing cupboard, the pipe coming up from the boiler has some sort of valve fitted, I wonder if it's an air bleed valve. It's just before the mid-position valve and it looks kinda similar to the ones on the pump.

 

[Armo74]

Perfect time to add some system cleaner and have a drain down to change the valve body. there is always a small possability of leaks on an older system, adding inhibitor is a must regardless. Would be a good idea to have the boiler serviced even if you haven't had any problems, you do with your car A picture of the valve you are talking about would help if you are curious as to what it is.

 

[iwilliams]

Perfect time to add some system cleaner and have a drain down to change the valve body. there is always a small possability of leaks on an older system, adding inhibitor is a must regardless. Would be a good idea to have the boiler serviced even if you haven't had any problems, you do with your car A picture of the valve you are talking about would help if you are curious as to what it is.

Thanks for your reply! Would the leaks from the radiators be on the valve connection? OK, it's just I've heard from somewhere that the inhibitor is no good for very old boilers - mine is Glow-worm Fuelsaver 55F. I've attached a picture of the valve in question, I think there's a BS 5154 marking on it. Would also appreciate if you could identify the thing in the 2nd picture, it's also part of the CH system and is above the hot water cylinder on a pipe coming from downstairs and going up to the F&E tank I think, maybe a vent pipe?

Also if I decide to fit a Honeywell valve in place of the Drayton one, are they compatible as in would I need to cut pipes etc.

Untitled

• iwilliams
• 2 Jun 2012
• 1

Untitled

• iwilliams
• 2 Jun 2012
• 1

 

[Armo74]

The valve in the first picture looks like an old gate valve, the second picture is an air separater. the pipework should be fine.

 

[iwilliams]

The valve in the first picture looks like an old gate valve, the second picture is an air separater. the pipework should be fine.

OK thanks. It seems I've got an open vented fully pumped system as the flow pipe from the boiler connects to the pump and then the mid-position valve. This pipe seems to carry on to that gate valve before joining with the return pipe from the hot water cylinder and presumably going back to the boiler. Does that mean it is a bypass valve as it's linking flow and return? So if I close off the pump valves and this bypass valve, I will be able to isolate supply for the motorised valve? Or does it still leave the pipes leading to the cylinder and radiators free? I'm trying to avoid draining down if I can as I'm weary the system is very old.

 

[Armo74]

It could be a bypass, it should link the flow to the return after the pump but before the valve, i would be surprised if it is as you are running on a y plan but that doesnt mean to say it isn't. You can avoid draining down by plugging your cold feed and vent pipe on your f/e tank, however draining down is the safest way if you are unsure what you are doing. As for turning off all the valves it is difficult to say without seeing the whole job.