Need help 3 port motorised valve failure or just actuator?

[stuart799]

Hello,

Here's some background on our setup - 2 bed split-level flat with indirect system upstairs, boiler downstairs. The motorised valve is stuck open so the CH comes on whenever HW is switched on. Motorised valve is 3 port (mid position) British Gas with the blue plastic cover (think it's Drayton) with quick release removal... The valve was fitted before we moved in, but sticker underneath says warranty expires in 2002. Valve 'looks' good, it's the shiniest thing in the system. Sine we moved in in May, HW was fine and radiators never came on, but recently the Mrs switched on the CH using the 1 hour boost, and since then the CH always comes on with the HW, and switching the CH on by itself has no effect.

I removed the actuator to see if the valve itself was frozen, and I can quite easily turn the valve from center to the HW position, but it doesn't like going the other way to the CH position. I was wondering how much these were supposed to move.

If possible I'd love to be able to swap out the actuator only. If I have to replace the whole valve I will, but I don't really want to drain down. I have replaced the gate valves and stopcocks on the system, so pretty handy at this but still a novice.

I have uploaded a photo of the valve with the actuator off. I can turn it from this position anticlockwise which is HW. It doesn't go clockwise past this position.

Any info would be helpful so I can crack this!

Thank you,

Stuart

Untitled

• stuart799
• 22 Oct 2011
• 1

 

[cross thread]

just fit new head ,check base is free as seized base causes the motor to burn out in the head

 

[45yearsagasman]

The travel on these valves is quite small. Run hot water program and then use a spenner to turn the valve to see if the heating port opens. If so then just replace the head. These are not like Honeywell valves in that they have a paddle type valve and are not prone to swelling like H/wells do on occasion.

 

[stuart799]

Hi all, so here's an update. I replaced the synchro motor on the valve first, but it still didn't work, so I got a new valve from screwfix. These things ain't cheap!

Wired in the new actuator and tried it with the existing valve but still didn't close on the CH side, so I had to replace the valve too. I had my suspicions that I would have to as most of the stuff in the flat is old and is clogged with scale.

I realised that the plumber who fitted the existing 3 port valve did a good job, as he put it higher than the hot water cylinder and the radiator, so the drain down was minimal (less than a bucket). I just started unscrewing the valve and drained it via a bin bag into the bucket. Then since I had it off anyway, I thought I would replace the pump with one of those A-rated ones from screw fix as the existing pump still worked but was noisy. The pump was less than the motorised valve!

So back to screwfix I went and got the pump. The old pump came off, but I could not get the bottom gate valve off as it was rusted on, so I had to go back out to get some because screwfix had been out of them. I did get the 1/4 turn ball valve ones, but they are a lot shorter than the gate valve ones and would have turned this into a bigger project so I needed to replace like for like. Went to Wickes, they were out of stock, but the price on the rack said £22 for a pair These are less than £3 each at screwfix, and even the pegler ones are cheaper than this. So then to Homebase where I finally found them for a tenner for a pair.

Got everything back together being real careful with the compression fittings, putting some ptfe tape on the olives and some joining compound on the threads. One thing that I couldn't figure out was how to refill and bleed the pump once everything was back on and I couldn't really find any tips online. In the end I undid the pipe that comes out of the pump and goes into the motorised valve, and poured water into it with a watering can without the watering attachment. It took a while, and I then bled the radiator, refilled some more, then bled the pump. The instructions state the you can run it dry for a little while, and it bleeds automatically, but I didn't want to take any chances.

All in all really happy with the way things went, and all is working perfectly!