Is my mid-position valve buggered?
Discussion
Can anyone help with my central heating issue?
Hot water is on, central heating is off (thermostat turned right down and off at the control unit) yet the radiators are still getting hot!
I'm guessing its the mid-position valve is nackered, as I understand it this controls the flow of hot water from the boiler to the hot water tank and the rads.
Cheers
Dave
Hot water is on, central heating is off (thermostat turned right down and off at the control unit) yet the radiators are still getting hot!
I'm guessing its the mid-position valve is nackered, as I understand it this controls the flow of hot water from the boiler to the hot water tank and the rads.
Cheers
Dave
It may well be the motor.
Even if the motor is working, sometimes they become too stiff for the spring to pull them 'round when de-energised. Most valves use the Synchron motor (although not all) which is easy to buy and fit from a Plumbers Merchant.
Alternatively it may be a really s
tty system which is not allowing the ball inside the valve to close, but that's a bit unlikely.
Edited to add:
I take it that the system HAS worked? Because incorrectly plumbed systems can do this.
Even if the motor is working, sometimes they become too stiff for the spring to pull them 'round when de-energised. Most valves use the Synchron motor (although not all) which is easy to buy and fit from a Plumbers Merchant.
Alternatively it may be a really s
tty system which is not allowing the ball inside the valve to close, but that's a bit unlikely. Edited to add:
I take it that the system HAS worked? Because incorrectly plumbed systems can do this.
Edited by Ferg on Friday 30th October 18:43
defo worked in the past, I have a valve to manually shut off the hot water tank so no water goes there, I've had a fiddle with switch hot water and CH off and on and the valve is definitely trying to do something whirring away, there is a little override slider on top of the valve to force it open.
I'll turn the electricity off in the morning and whip the cover off the motor and give it a prod!
Hopefully the motor is a replaceable item and I dont have to do the whole vavle, looks simple enough but also looks like I might be getting a bit wet while doing it!
Thank you both for your help!
Edited by davido140 on Friday 30th October 19:28
Mine just done that, it was a bit sticky so I used the manual valve a couple of times and it freed up. I also previously had a problem with the microswitch on one of them which meant the pump would run continuously. £50 for a new valve or 50p for a new microswitch from Maplins. I chose the latter, still going strong 3 years later.
I assume we're talking about the same valves here??
I assume we're talking about the same valves here??
davido140 said:
Hopefully the motor is a replaceable item and I dont have to do the whole vavle, looks simple enough but also looks like I might be getting a bit wet while doing it!
Thank you both for your help!
Given that the manual override worked, I'd suspect the valve itself is OK and it's just the servo that has failed. That's relatively cheap and easy to replace, it's a practical DIY job if you're comfortable dealing with mains voltage wiring and doesn't involve getting wet.Thank you both for your help!
Simpo Two said:
(NB: Why are rad valves such a pain to open/close? Can't they be 1/4 turn ceramic jobbies like taps?)
Not fine enough adjustment on a ceramic disc tap for balancing, AND (as you will discover at some point) ceramic disc taps are st and suffer from scratching in hard water. A 15p washer is a better fix than a £15 cartridge, John.Ferg said:
Simpo Two said:
(NB: Why are rad valves such a pain to open/close? Can't they be 1/4 turn ceramic jobbies like taps?)
Not fine enough adjustment on a ceramic disc tap for balancingFerg said:
Not on the lockshield end hopefully......
That's a new one on me but it's the end with the bigger knob with the rotation arrows on it (the one that's always too stiff when winter comes and you can't grasp it properly because it's too close to the wall so you end up pulling the plastic bit off and getting some pliers on the square jobbie underneath...NB - you still interested in quoting to fit a larger HW cyclinder?
Simpo Two said:
Ferg said:
Not on the lockshield end hopefully......
That's a new one on me but it's the end with the bigger knob with the rotation arrows on it (the one that's always too stiff when winter comes and you can't grasp it properly because it's too close to the wall so you end up pulling the plastic bit off and getting some pliers on the square jobbie underneath...NB - you still interested in quoting to fit a larger HW cyclinder?
My valve has been replaced after it burned out the original and a replacement motor.
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My valve has been replaced after it burned out the original and a replacement motor.
Screwfix are your friends
http://www.screwfix.com/search.do;jsessionid=M52KS...
Screwfix are your friends
http://www.screwfix.com/search.do;jsessionid=M52KS...
odyssey2200 said:
My valve has been replaced after it burned out the original and a replacement motor.
Screwfix are your friends
http://www.screwfix.com/search.do;jsessionid=M52KS...
Honeywell or Drayton (ACL), but I wouldn't go near the others!!!Screwfix are your friends
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I replaced my mid position valve last weekend after experiencing the same symptoms, caused by a seized spindle in the valve. It's a simple enough job; I found it cheapest to buy a complete valve from Ebay and swap the guts into the existing valve body.
However, my original valve was a fairly old Honeywell and on those you can't separate the motor assembly from the valve mechanism. On the new valves you can, so next time it happens I'll be able to replace just the top plate of the valve. That'll be about £12 retail instead of £80-ish (fwiw, I paid about half that on Ebay). Worth checking what type of valve you have - Google the model number.
My top tip for those contemplating mid-zone valve surgery: you will need to drain the system down a bit. Before starting work, ensure that you have the appropriate size spanner for the drain cock to hand as well as some replacement washers in case the one that's in there won't re-seal. That would have saved me an hour or two. It would also be no bad thing to have a bottle of corrosion inhibitor handy for when you re-fill, else your next problem may be leaking radiators! (I was fortunate to have one kicking around in the loft; god forbid I should actually plan a job).
However, my original valve was a fairly old Honeywell and on those you can't separate the motor assembly from the valve mechanism. On the new valves you can, so next time it happens I'll be able to replace just the top plate of the valve. That'll be about £12 retail instead of £80-ish (fwiw, I paid about half that on Ebay). Worth checking what type of valve you have - Google the model number.
My top tip for those contemplating mid-zone valve surgery: you will need to drain the system down a bit. Before starting work, ensure that you have the appropriate size spanner for the drain cock to hand as well as some replacement washers in case the one that's in there won't re-seal. That would have saved me an hour or two. It would also be no bad thing to have a bottle of corrosion inhibitor handy for when you re-fill, else your next problem may be leaking radiators! (I was fortunate to have one kicking around in the loft; god forbid I should actually plan a job).
GreenV8S said:
In that case I suspect you've never balanced your radiators, which might explain why you find yourself trying to adjust them all come winter time.
You misunderstand me - I'm not 'trying to adjust them all come winter time'. To me a radiator is principally either on or off, controlled by the valve on bottom right-hand corner. Open = hot, closed = cold. Being 1988 vintage, they don't have individual thermostats, there is just one room thermostat in the lounge. Apart from some rad valves being stiff, it's worked fine for 21 years Back to the OP.
Simpo Two said:
GreenV8S said:
In that case I suspect you've never balanced your radiators, which might explain why you find yourself trying to adjust them all come winter time.
You misunderstand me - I'm not 'trying to adjust them all come winter time'. To me a radiator is principally either on or off, controlled by the valve on bottom right-hand corner. Open = hot, closed = cold. Being 1988 vintage, they don't have individual thermostats, there is just one room thermostat in the lounge. Apart from some rad valves being stiff, it's worked fine for 21 years Back to the OP.
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