Leaking radiator valves, Can this be repaired?

[DIYDonnel]

Hi

I've read through quite a few posts on this forum about leaking valves but I'm sure my radiator is leaking from a different place. When I put the heating on and top up the system the radiators get hot but then the small one in the bathroom starts leaking. Mostly from the "adjustable" valve end but also from the other end (I'm not sure if radiators actually have ends but it's the one that the arrow in the knob, it's quite old so it's not got a temperature one).

I can see the leak is coming from the top screw that you turn to adjust it (pic below with the big red arrow), if I close it tight it seems to leak even faster, it's not running but it's dripping quite fast.

Can I fix this or do I need to get a new valve? If I get new valves for both ends does it matter what end I put the thermostat on?

BTW this isn't MY valve, it's just a generic pic from the web

 

[Slugbabydotcom]

Get your spanner out and tighten that nut!
It's a case of finding a balance between having a leak if its not tight enough and not being able to turn the valve on and off if its too tight.

There is packing material under that there nut. In bad cases it needs replacing. Holding the shaft still undo the nut and lift it up the shaft a bit. I would then loosely wrap packing material [usually ptfe tape] loosely around the shaft and push it into place with one of those small electricians neon testing screwdrivers or similar. Then re-tighten the nut.

The same principle applies to mains stoptaps. Sometimes for those I have been known to use string with some form of grease as a packing material.

Beware! I did come across one make of valve where this nut was a left hand thread.
From experience the one in the pic is a right hand thread.

 

[oph]

Its known as the packing gland and it needs very little with a spanner to take up the slack go gentle with it.
PS Clockwise !!!

 

[DP]

Some valve spindles do not have packing. O rings hold back the water when gland is not packed. A picture of a valve that is 'off the web' is very misleading as your valve may only look similar visually but could be entirely different internally.

As suggested, tighten the nut and if that fails, dismantle and see why it is weeping.

 

[DIYDonnel]

Thanks for the quick replies. I'm at work right now so I can't take a pic of my actual valve, I understand it might be different inside so I'll take a picture when I get it.

So even though the water is coming out of the top of the "bolty bit" (is that the packing gland?) that the "water flow screw" goes in to it's the bolt that is connected - in the pic - to the chrome part that needs tightening? The water is literally spilling up through the threads where the water flow screw is attached in the bolt.

Does anyone have a link to a diagram that has the names of all the parts, I feel like I might be misleading because I don't know what anything is called.

Thanks again

 

[pompeyal]

Hi

If I get new valves for both ends does it matter what end I put the thermostat on?

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The thermostatic valve if fitted should be fitted to the flow side of the radiator.

 

[DP]

The thermostatic valve if fitted should be fitted to the flow side of the radiator.

Not true in every case.

 

[DIYDonnel]

Oh it's okay, I'm not going to get a TRV because it's in the bathroom

 

[Agile]

The TRV can be fitted in any room as long as there is an auto bypass valve or at least one rad has not TRV.

They are best fittted on the flow although current ones can be fittted either end as they have a stronger spring.

Tony

 

[TicklyT]

Valves with 'proper' glands usually have two seperate hexagons ('bolty bits') around the valve spindle. The lower is for tightening the valve head gear into the valve body (chrome bit). This section is usually fully tightened.

The upper (usually smaller) hex. is adjusted to compress the packing against the spindle to seal it, but still allow it to rotate.

Some valves only have a single hex. fixing the bonnet to the valve, and rely on 'O' rings fitted in grooves inside the head gear to seal the spindle. These are not usually regarded as repairable because:-
1. their relatively low cost.
2. the difficulty of dismantling them to replace the seal (more work than replacement).
3. the mixed results following repair.

 

[Agile]

As a temporary bodge its sometimes possible to wind PTFE taps round the "O" rings after removing the nut on the type which uses "O" rings.

But sometimes a considerable leak will occur although reducing system pressure on a pressurised system will reduce this.

Tony

 

[JPC]

what you mean temporary repair....done some years ago and Plumbers Tape For Everything still holdling good !!

 

[Agile]

Well I suppose tying up your exhaust with string is still a temporary a year later.

But the MOT is unlikely to accept that as an adequate support.

Unfortunately there is no MOT for boilers!

Tony

 

[DIYDonnel]

Hi again

Sorry I didnt manage to take a pic, I've been chiselling away at door frames - the life of a DIYer. Anyway, I've decided to replace the valves and I have 2 new ones, a few wrenches, a radiator key and some ptfe tape. The radiator seems to have well and truly leaked the water out and all the other radiators upstairs get hot and stay hot when I turn the heating on so do I still need to drain the whole system???

Thanks for all the replies

 

[JohnD]

If you are going to the trouble of fitting new rad valves, you might as well fit TRVs while you are at it, and change the rad valves that are not leaking yet if they are the same age as the ones that are.

You will have to turn off your boiler and drain down first, the extra work of bunging it and doing the rads one at a time is not worthwhile.

This would also be a good time to take the rads into the garden and hose out the old sediment. Hot summer is the best time for working on your CH, especially if you have a HW cylinder with an immersion heater as backup.

Remember to clean out your F&E tank (if you have one) before you start draining, and to include a corrosion inhibitor on final fill after you have ensured there are no leaks.