Stuck Domestic Thermostatic Radiator Valves.

macabethiel · 03-01-2015, 14:06

When the warmer weather comes I will drain down the central heating system and replace a couple of my older thermostatic radiator valves as they tend to stick after a rest during the summer.

In the meantime any tips on how to persuade them to open again ?
Usually I can give the body a tap as I unscrew them and they start to open but one seems rather stubborn and will not submit to my gentle treatment.

Any plumbers or experienced central heating engineers amongs our members with a tip for a short term fix until spring?

solarman216 · 03-01-2015, 14:29

Quote:

Originally Posted by macabethiel

When the warmer weather comes I will drain down the central heating system and replace a couple of my older thermostatic radiator valves as they tend to stick after a rest during the summer.

In the meantime any tips on how to persuade them to open again ?
Usually I can give the body a tap as I unscrew them and they start to open but one seems rather stubborn and will not submit to my gentle treatment.

Any plumbers or experienced central heating engineers amongs our members with a tip for a short term fix until spring?

what is the make and model of the valve? Rick

macabethiel · 03-01-2015, 14:42

I have attached a photo as I can't tell if its a MA or a WWV ?

Cant work out how to take the knob bit off either my other one has a simple screw collar this one is all plastic looking !

Ianinessex · 03-01-2015, 15:36

I had some a bit like this, the plastic top which houses the thermostat was held onto the valve by a collet style fitting. the collar had to be pushed or twisted back towards the main plastic part and this released the grips of the collet enabling the plastic part to be removed.
Once the plastic bit is off, the valve body has a small brass pin that goes into the valve. If it is working, you can push the pin in to close the valve. You need to use something like the flat of a bit screwdriver to spread the load as it has a strong spring, or a pair of pliers to grip the top end of the pin, but be careful not to bend or damage the pin. When you stop pushing, the pin should come back out with the force of the spring. If the valve has stuck shut, the usual problem, I grip the pin with the pliers and move it in and out briskly a few times. This normally frees the valve and the pin will stay out in the "valve fully open" position.

Hope this helps

rustic · 03-01-2015, 15:52

When I have bought and fitted similar valves, they came with a manual over ride knob. Which often gets discarded... except in my house lol...

You removed the top part, leaving the pin, then screwed on a plastic knurled knob, that pressed down on the pin as you screwed down on the plastic knob.

So the information in previous posts is correct.

What I would do, is remove the top, and make a bund out of plastercine and fill with WD 40, so some soaks down the pin hole.
Then work the pin with vertical pressure, without bending the pin, or pening over the end.

As with any radiator valve, they prefer to be seized up than free running, so it's worth working both valves at the ends of each radiator every year or so... but this doesn't happen in real life, and when you do try them....they leak...

Mind you... the lock shield valves are around a £1 or so...

Mobieus_uk · 03-01-2015, 17:51

Welcome to my world, this is what i do for living, they can normally always be freed up by tapping down on the pin when you remove the thermostatic head, if that doesn't work then a few sharp taps from the side can help, the reason they are sticking in the first place if that you probably have contaminated water in your heating system so its worth probably flushing the system

If your any good at plumbing try and cut in one of those magnetic cleaners on the return pipe back to the boiler http://www.adey.com/installers/filte...n-professional
they work really well and you can use them do add inhibitor to your heating system.

Dont underestimate the importance of a decent inhibitor like http://www.sentinelprotects.com/uk/p...x100-inhibitor as this will slow down the corrosion thats going on on the system, i say slow down because you can never stop it, this is why chemist refer to water as the universal solvent but you can slow it down to get a good life expectancy out of the system

If you system is on the old type that is you have a tank in the loft look for signs of it getting warm (pumping over)as this could be a indication that the cold feed is partially blocked and will cause all sorts of issues with water quality

macabethiel · 05-01-2015, 15:00

Quote:

Originally Posted by Ianinessex

I had some a bit like this, the plastic top which houses the thermostat was held onto the valve by a collet style fitting. the collar had to be pushed or twisted back towards the main plastic part and this released the grips of the collet enabling the plastic part to be removed.
Once the plastic bit is off, the valve body has a small brass pin that goes into the valve. If it is working, you can push the pin in to close the valve. You need to use something like the flat of a bit screwdriver to spread the load as it has a strong spring, or a pair of pliers to grip the top end of the pin, but be careful not to bend or damage the pin. When you stop pushing, the pin should come back out with the force of the spring. If the valve has stuck shut, the usual problem, I grip the pin with the pliers and move it in and out briskly a few times. This normally frees the valve and the pin will stay out in the "valve fully open" position.

Hope this helps

So do I need a small screwdriver inserting between black plasic bit and the bottom of the white knob to prize it upwards with the valve in the open position then ?

Ianinessex · 05-01-2015, 15:12

Quote:

Originally Posted by macabethiel

So do I need a small screwdriver inserting between black plasic bit and the bottom of the white knob to prize it upwards with the valve in the open position then ?

It is best with the knob in the fully open position as that is putting no pressure on the valve.
As to exactly how to remove the plastic thermostat, I do not know and can not see from the picture. Some have a screw fitting, some a sliding collet and I think some just clip on. All I can suggest is gentle twisting and/or levering at the point it joins and see if something moves. You will be looking for a movement that releases the grip of the collet "teeth" onto the valve.

03-01-2015, 14:06	#1
macabethiel Senior Member Join Date: Aug 2008 Location: Derby Vehicle: Freelander & Jeep GC 3.0 Posts: 4,416	Stuck Domestic Thermostatic Radiator Valves. When the warmer weather comes I will drain down the central heating system and replace a couple of my older thermostatic radiator valves as they tend to stick after a rest during the summer. In the meantime any tips on how to persuade them to open again ? Usually I can give the body a tap as I unscrew them and they start to open but one seems rather stubborn and will not submit to my gentle treatment. Any plumbers or experienced central heating engineers amongs our members with a tip for a short term fix until spring?

03-01-2015, 14:42	#3
macabethiel Senior Member Join Date: Aug 2008 Location: Derby Vehicle: Freelander & Jeep GC 3.0 Posts: 4,416	Cant make out the make its either MA or WV I have attached a photo as I can't tell if its a MA or a WWV ? Cant work out how to take the knob bit off either my other one has a simple screw collar this one is all plastic looking !

03-01-2015, 15:52	#5
rustic Senior Member Join Date: Feb 2007 Location: Staffordshire Vehicle: Maverick Mk I 2.7 TD LWB Posts: 7,825	When I have bought and fitted similar valves, they came with a manual over ride knob. Which often gets discarded... except in my house lol... You removed the top part, leaving the pin, then screwed on a plastic knurled knob, that pressed down on the pin as you screwed down on the plastic knob. So the information in previous posts is correct. What I would do, is remove the top, and make a bund out of plastercine and fill with WD 40, so some soaks down the pin hole. Then work the pin with vertical pressure, without bending the pin, or pening over the end. As with any radiator valve, they prefer to be seized up than free running, so it's worth working both valves at the ends of each radiator every year or so... but this doesn't happen in real life, and when you do try them....they leak... Mind you... the lock shield valves are around a £1 or so... __________________ Ford Maverick GLX 1995 2.7TD LWB in illusion silver, 98k miles. Owned since new, for 22 years. Best car I have ever owned. Just wish I could drive it more.

03-01-2015, 15:36	#4
Ianinessex Senior Member Join Date: Sep 2014 Location: Leigh-on-Sea, Essex Vehicle: Patrol GR SE+ TD/A 2002 Posts: 207	I had some a bit like this, the plastic top which houses the thermostat was held onto the valve by a collet style fitting. the collar had to be pushed or twisted back towards the main plastic part and this released the grips of the collet enabling the plastic part to be removed. Once the plastic bit is off, the valve body has a small brass pin that goes into the valve. If it is working, you can push the pin in to close the valve. You need to use something like the flat of a bit screwdriver to spread the load as it has a strong spring, or a pair of pliers to grip the top end of the pin, but be careful not to bend or damage the pin. When you stop pushing, the pin should come back out with the force of the spring. If the valve has stuck shut, the usual problem, I grip the pin with the pliers and move it in and out briskly a few times. This normally frees the valve and the pin will stay out in the "valve fully open" position. Hope this helps

03-01-2015, 17:51	#6
Mobieus_uk Senior Member Join Date: Aug 2014 Location: Tonbridge Vehicle: Terrano ii SE+2.7tdi Posts: 232	Welcome to my world, this is what i do for living, they can normally always be freed up by tapping down on the pin when you remove the thermostatic head, if that doesn't work then a few sharp taps from the side can help, the reason they are sticking in the first place if that you probably have contaminated water in your heating system so its worth probably flushing the system If your any good at plumbing try and cut in one of those magnetic cleaners on the return pipe back to the boiler http://www.adey.com/installers/filte...n-professional they work really well and you can use them do add inhibitor to your heating system. Dont underestimate the importance of a decent inhibitor like http://www.sentinelprotects.com/uk/p...x100-inhibitor as this will slow down the corrosion thats going on on the system, i say slow down because you can never stop it, this is why chemist refer to water as the universal solvent but you can slow it down to get a good life expectancy out of the system If you system is on the old type that is you have a tank in the loft look for signs of it getting warm (pumping over)as this could be a indication that the cold feed is partially blocked and will cause all sorts of issues with water quality