Is this an isolating valve?

[Poddler]

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• Poddler
• 20 Nov 2011
• 1

I thought this was an isolating valve, there being another on the other side of the CH circulating pump, but I've not seen this style before (fitted by British Gas). Is it? As promised in FAQ, the moment I moved it in either direction it started to spray water. Luckily it stopped doing so when put back in its original position. Or is it actually a bleed valve?

Advice appreciated.

 

[Slugbabydotcom]

It is an isolating valve and a 90 degree turn will operate it. The other 'gatevalve' type with which you are more familiar are less bothersome as these quarter turn variety often leak as you just discovered and have to be replaced.

 

[adlplumbing]

rubber gone inside it may need replacing but if you put some siclon grease into it and some ptfe round it will be short term fix

 

[gas_man_gaz]

yep, its a pump isolation valve.. bg went through a stint of fitting these as they are cheaper. if i was you i wouldn't use it as they normally leak and normally carry on leaking.. what are ya trying to do?

 

[Poddler]

Heating is not coming on, though radio receiver from thermostat is showing green light for heating demand, and boiler runs OK to provide hot water. So I was going to remove the bleed screw from the centre of the pump (Grundfoss UP 100 rebadged by British Gas) and check circulator had not seized.

There are two motorised valves in system, Drayton (BG rebadged again) with removable plastic operating tops. The metal valves move by hand OK when the tops are removed, but who knows whether the actuators are doing anything - no noise, nothing apparent.

 

[Whitespirit66]

Put a bowl under the pump and remove the pump's screw cap. Only a very small trickle of water will come out of the pump with cap removed.

 

[Hugh Jaleak]

If HW is ok, chances are it may be motorised valve on CH side that isn't working. Remove the head from CH valve, you say spindle moves ok, then switch heating on. Does actuator in valve head move?

 

[gas_man_gaz]

prob wont be the pump..
wen ya turn the ch on using the wireless stat, the receiver turns green, can ya hear the receiver click?
also check if the ch valve has moved to the b position

 

[Poddler]

Right - this is useful stuff. Thank you.

When the wireless stat is operated the red LED flashes the prescribed 7 times which confirms it is receiving a signal. Red then goes out, and as green lights there is a click from the receiver.

Picture below shows the layout. I assume the blue actuator on the left is the CH one, since the other is fitted right next to the HW tank.

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• Poddler
• 20 Nov 2011
• 1

I had both actuators unclipped from the pipework while Mrs Poddler operated the wireless thermostat as above. Neither clicked, chirped, moved, or gave any other sign of life when the receiver clicked and lit the green LED. And both resolutely continued to point to A, as in the pic below. Does this behaviour offer any pointers, pl?

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• Poddler
• 20 Nov 2011
• 1

 

[Hugh Jaleak]

Left should be CH. This should move when stat calls fot heat. Try moving lever to B manually, does boiler/pump then run?

 

[Poddler]

Should the lever move easily? Seems pretty tight (sprung?) and reluctant to do more than move a few millimetres. Nothing to break if I give it a bean or two?

 

[Hugh Jaleak]

These valves contain a spring, the motor powers the valve open, when power is removed, (thermostat satisfied), the spring winds the valve shut again. I'd expect slight resistance, anything more may break something but could also indicate valve is knackered.

I'd be inclined to do some basic electrical tests just to confirm that power is getting to the valve before condemning it though.

 

[Poddler]

Thanks.

 

[Poddler]

Sorry - more info and questions. Once unlocked, black lever moved gently across under finger pressure with slight whirring noise, the gears presumably. Pump then started up, but boiler didn't. Cold water being pumped. Let go of black lever, slowly returned to original position. Possible to latch it down in 'pump operating' position. Left it for a few minutes like this and boiler has now kicked in and radiators are warming.

Looks as if I should replace the actuator (subject to electrical tests mentioned above). I assume I need to know whether I am dealing with a two or three position valve to do that. How do I establish that, bearing in mind the part no on the label is British Gas not Drayton? It says "Valve Actuator Code BGMVSP-9" and there is another BG code "555213" towards the bottom of the label, in case anyone recognises it.

 

[Poddler]

Nothing like answering my own questions, is there?!

More research on the net has revealed that the Drayton equivalent part no for the actuator is 27653, for use with a Drayton ZA6/779- 2 zone valve.