How do you take off this float valve in the loft cold water tank?

[spader]

The existing valve has a male threaded 1/2" BSP tail. This takes the backnut and the pipe connection. More common to see a tap connector screwed straight on, rather than an elbow like yours, but in any case you need to take off everything outside to remove the valve.
When you've got it off, why not dismantle it and replace the rubber washer, and give things a smear of silicone grease? It should be good then for 20-odd years!

Great info and and advice. I have already bought a new replacement float valve Type2. I was under presumption that all these valves would be same fitting design. But obviously they are not. I will take the whole valve off the tank, and replace with the new Type2 float valve.

Thanks.

 

[Alec_t]

To remove the old valve, couldn't you leave the elbow in place and just:
1) remove the split pin,
2) detach the float arm and float,
3) slacken off the back nut 4 slightly,
4) put grips on the elbow (to hold it steady),
5) put grips/spanner on the valve body,
6) rotate the valve body to unscrew it from the elbow.
?

 

[spader]

To remove the old valve, couldn't you leave the elbow in place and just:
1) remove the split pin,
2) detach the float arm and float,
3) slacken off the back nut 4 slightly,
4) put grips on the elbow (to hold it steady),
5) put grips/spanner on the valve body,
6) rotate the valve body to unscrew it from the elbow.
?

Great idea too. I will try that way first, and if it didn't work then take the elbow off.
Thank you Alec.

 

[spader]

I had to leave the old float valve as is, because it is solidly stuck on the fitting hard, both from inward and at the back it wouldn't even try to come off or move slightest. I just left it due to possible breakage on the tank, if I forced more.

And the other problem was that I didn't have the replacement fittings for the elbow connector such as new olives for fitting them back.
And it was not elbow connector but a TEE connector.

But I managed to fit in a new ball lever valave under the old gate valve. It works great.

I took off the arm from the old float valve, bent it a lot, and refitted it to the valve body.
The old float valve with the bent arm refitted still works, and now the water level stops way below the overflow pipe. (about 2 inches lower than the previous highest water level) stopping the overflow of the cold tank.

I would still like to replace the old float valve with the new type2 float valve.
I must find out how to undo and take off the old float valve from the tank without breaking or cracking the tank.
I wonder if box spanners might work undoing the nut, which looks like stuck rock solid hard with some kind of adhesive for many many years.

And the TEE connector at the back does look different from the ones availabe I see online. Could it just be refitted back after replacing the float valve with new olives and maybe washers? Or the TEE connector must be replaced with the new one? In that case, I must get the new parts for the replacement. Not sure now what would be the best way to go.

 

[Madrab]

It'll be old boss white - thread sealer - as it's a female fitting.

You only need the right heavy duty tools. Yet to find a brass to brass fitting that wouldn't eventually budge.

Thee teee you'd use would be one of these - https://www.screwfix.com/p/pegler-px54-brass-compression-adapting-tee-22mm-x-22mm-x-3-4-/4089g.

I'm sure you could re-use the one that's there though. Bit of tape around the old olives to stop them weeping when re-fited.

 

[spader]

It'll be old boss white - thread sealer - as it's a female fitting.

You only need the right heavy duty tools. Yet to find a brass to brass fitting that wouldn't eventually budge.

Thee teee you'd use would be one of these - https://www.screwfix.com/p/pegler-px54-brass-compression-adapting-tee-22mm-x-22mm-x-3-4-/4089g.

I'm sure you could re-use the one that's there though. Bit of tape around the old olives to stop them weeping when re-fited.

Will look into these, and plan for the 2nd attempt in due course.
Thanks for great info and advice.

 

[fixitflav]

Will look into these, and plan for the 2nd attempt in due course.
Thanks for great info and advice.

Bosswhite softens up with a blowtorch, but not when it's on a plastic or GRP tank like yours.

You could change the rubber washer without removing the valve. Pull out the split-pin, that releases the arm. Unscrew the end cap and the thingy inside comes out. You might to warm the end cap, but that's quite a distance from the tank wall. The "thingy" is in 2 parts screwed together, containing the rubber washer. If you have to heat that to unscrew it it doesn't matter as the rubber will be replaced.

 

[robinbanks]

I must find out how to undo and take off the old float valve from the tank without breaking or cracking the tank.

If all else fails, angle grinder. Cutting it off would be a lot less stressful on the tank than leaning on the fitting with big spanners, but if you are going to wrench it, make sure you're gripping the valve body with something and applying the opposite rotation force to the valve body as you're applying to the nut, rather than expecting the tank to take the full force of stopping the valve body rotating while you turn the nut

 

[spader]

Bosswhite softens up with a blowtorch, but not when it's on a plastic or GRP tank like yours.

You could change the rubber washer without removing the valve. Pull out the split-pin, that releases the arm. Unscrew the end cap and the thingy inside comes out. You might to warm the end cap, but that's quite a distance from the tank wall. The "thingy" is in 2 parts screwed together, containing the rubber washer. If you have to heat that to unscrew it it doesn't matter as the rubber will be replaced.

Thanks for your instruction on replacing the rubber washer in the old float valve.

I have been monitoring the old float valve after the arm bending adjustment, and it seems working fine keeping safe water level and not over flowing anymore. So I will keep monitoring it for a while until it goes malfunctioning again. But also pre-planning total replacement of the float vlave to the new Type 2 float valve which I have bought, and ready to be installed. But there are some points I don't understand in the system such as why some unknown plastic pipe is attached to the mains rise pipe into the cold water tank, and what is the size of the TEE connector to the old float valve, and would it fit to the newly bought type2 float valve (which seems 15mm)?? The old float valve connection to the TEE seems 22mm. Should I get rid of the old TEE, and just get a copper pipe and bend it 90 degrees and fit it to the new float valve - would it be better? etc tec.

I am trying to fully understand how the whole system works, and also find out which option would be best making it reliable water system here.

 

[fixitflav]

Thanks for your instruction on replacing the rubber washer in the old float valve.

I have been monitoring the old float valve after the arm bending adjustment, and it seems working fine keeping safe water level and not over flowing anymore. So I will keep monitoring it for a while until it goes malfunctioning again. But also pre-planning total replacement of the float vlave to the new Type 2 float valve which I have bought, and ready to be installed. But there are some points I don't understand in the system such as why some unknown plastic pipe is attached to the mains rise pipe into the cold water tank, and what is the size of the TEE connector to the old float valve, and would it fit to the newly bought type2 float valve (which seems 15mm)?? The old float valve connection to the TEE seems 22mm. Should I get rid of the old TEE, and just get a copper pipe and bend it 90 degrees and fit it to the new float valve - would it be better? etc tec.

I am trying to fully understand how the whole system works, and also find out which option would be best making it reliable water system here.

None of the pics show where the grey plastic pipe goes, so can't comment on that. I assume the copper pipe over the far corner is the vent pipe from the DHW cylinder.
By Type 2, do you mean this? Screwfix website calls it Part 2.

That type is better than your Part 1 valve, less chance of sticking due to scale round the plunger, but I'm not sure I'd bother replacing it now you seem to have solved the problem, without even replacing the washer. It will be threaded 1/2" BSPM like the existing. More usual to use a tap fitting (straight or elbow), doubt if it has a taper for an olive, but you can use a female threaded fitting like the existing, with PTFE tape.
I can't see why a tee and upstand has been used, maybe the guy had a tee and a bit of pipe to hand, but no elbow!

 

[spader]

None of the pics show where the grey plastic pipe goes, so can't comment on that. I assume the copper pipe over the far corner is the vent pipe from the DHW cylinder.
By Type 2, do you mean this? Screwfix website calls it Part 2.
View attachment 288854
That type is better than your Part 1 valve, less chance of sticking due to scale round the plunger, but I'm not sure I'd bother replacing it now you seem to have solved the problem, without even replacing the washer. It will be threaded 1/2" BSPM like the existing. More usual to use a tap fitting (straight or elbow), doubt if it has a taper for an olive, but you can use a female threaded fitting like the existing, with PTFE tape.
I can't see why a tee and upstand has been used, maybe the guy had a tee and a bit of pipe to hand, but no elbow!

Yes, that is still mystery to me. I will try to dig into the fibre glass insulation pile where the plastic pipe has dug into.
Yes, the copper pipe floating at the corner seems the vent pipe from the Hot Water Boiler from downstairs kitchen. Not sure what it does either. OK it vents, but why and what?

Yes, the Type2 float valve in the photo is the exact one I bought from SFx.
The TEE and raised end pipe and the grey pipe filling water into the cold water tank, are all pile of mysteries to me, and at one point I even thought that the plumber doing the job originally maybe 50 year ago had run out of a long copper pipe or couldn't find a 90 elbow in his van, so just picked up a TEE and offcut pipe, and did the job? Or maybe there had been some operartional reasons for that setup, I wan not sure.

 

[denso13]

Not sure what it does either. OK it vents, but why and what?

It vents from the hot water cylinder to provide a route for overheated water/pressure rises.

The TEE and raised end pipe and the grey pipe filling water into the cold water tank, are all pile of mysteries to me, and yes I thought that the plumber doing the job originally maybe 50 year ago had run out of a long copper pipe or couldn't find a 90 elbow in his van, so just pick up a TEE and off cut pipe, and did the job?

You know what is now

 

[spader]

If all else fails, angle grinder. Cutting it off would be a lot less stressful on the tank than leaning on the fitting with big spanners, but if you are going to wrench it, make sure you're gripping the valve body with something and applying the opposite rotation force to the valve body as you're applying to the nut, rather than expecting the tank to take the full force of stopping the valve body rotating while you turn the nut

I have a suspicion that angle grinder for the copper pipe fittings would be overkill? Maybe I just need some larger heavy duty spanner or the Stilson pipe wrench? I have ordered big Bahco spaners and pipe wrench from Amazon, and they are on my way.

 

[spader]

It vents from the hot water cylinder to provide a route for overheated water/pressure rises.

You know what is now

Yes, I think that is it. Thanks for the info. The grey plastic pipe mystery still remains.

 

[fixitflav]

Yes, that is still mystery to me. I will try to dig into the fibre glass insulation pile where the plastic pipe has dug into.
Yes, the copper pipe floating at the corner seems the vent pipe from the Hot Water Boiler from downstairs kitchen. Not sure what it does either. OK it vents, but why and what?

Yes, the Type2 float valve in the photo is the exact one I bought from SFx.
The TEE and raised end pipe and the grey pipe filling water into the cold water tank, are all pile of mysteries to me, and at one point I even thought that the plumber doing the job originally maybe 50 year ago had run out of a long copper pipe or couldn't find a 90 elbow in his van, so just picked up a TEE and offcut pipe, and did the job? Or maybe there had been some operartional reasons for that setup, I am not sure.

Do you have a feed/expansion tank for the heating (primary) circuit? That would have a vent pipe over the tank. The one over the storage tank more likely from the DHW cylinder (secondary circuit) (assuming you have one).