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

[denso13]

The grey plastic pipe mystery still remains.

It is undoubtedly a connecting to the main pipework feeding something else.

 

[fixitflav]

Just noticed the other thread on this subject

 

[spader]

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).

Yes, we have this old immersion heater boiler / expansion tank in the kitchen. The heater has stopped working - maybe it has burnt the element in the tank due to age. It still seems storing and feeding water to the taps to the upstairs bath, and also downstairs shower room basin taps, although it is just cold water. We have been using the electric showers (MIRA) for the hot water.

 

[spader]

It is undoubtedly a connecting to the main pipework feeding something else.

I have been suspecting it could be the electric shower. But when the pipe was filling in the water tank, instead of sending out water, I was totally lost. Could it be some type returning water in the chain?

 

[spader]

Just noticed the other thread on this subject

Yes, this is a part of the bunch of different problems of the old water system in this house.

 

[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!

Is there any possibility that the old float valve in the water tank could be undone, and detached from its own fitting juist like the new Type2 float valves?
Now I have got big Bahco spanners and Pipe Wrenches, and can attack the old float valve trying to undo it. But just wondering if it is originally one piece device which cannot be separated from the fitting, or maybe it is 2 piece which could be undone from the fitting by grabbing the internal part in the tank, and tunrning with the mighty pipe wrench.

 

[fixitflav]

Is there any possibility that the old float valve in the water tank could be undone, and detached from its own fitting

No, the body is in one piece, as several posters have said, and you can see from your pics. The only dismantling you can do is what I suggested in #22, either in situ or after removing it.

Now I have got big Bahco spanners and Pipe Wrenches, and can attack the old float valve trying to undo it

You can use them to remove the valve. Need to loosen the back nut first, which might be a bit tricky as it is rather shallow. A well-fitting open-end spanner could be the best bet. And do it as robinbanks said in #23, to avoid putting force on the tank wall.

 

[spader]

No, the body is in one piece, as several posters have said, and you can see from your pics. The only dismantling you can do is what I suggested in #22, either in situ or after removing it.

You can use them to remove the valve. Need to loosen the back nut first, which might be a bit tricky as it is rather shallow. A well-fitting open-end spanner could be the best bet. And do it as robinbanks said in #23, to avoid putting force on the tank wall.

I have taken a break for the holiday. Fortunately the old float valve has been working with the bent arm.
But it really has to be replaced with the new one. And now I see part of the old copper pipe feeding it has problems too. Close inspection on the photos reveal the copper pipe is in bad shape showing the signs of rotting and rusting.

Yes, your points on 22 and 23 seem very crucial. I was looking at the photos of the old fittings today, and it looks really tricky thing to undo due to the shallow nut which looks like made of some type of old plastic material, stuck hard and perhaps rotted into the surface of the tank.

 

[spader]

I am planning to cut off the copper pipe above the plastic TEE, and replace it with new 15mm copper pipe using 22 to 15 reducer with another full bore valve in the link, and connect it with either with 90 elbow to the new flot valve or bending the new 15mm pipe 90 into the new float valve. But taking off the old float valve from the tank is major tricky job before that I suppose.

 

[spader]

Is there any chemical that could loosen the frozen up bolt with the adhesive? How about the carb cleaner or acetone?

 

[denso13]

Is there any chemical that could loosen the frozen up bolt with the adhesive?

Just use large enough grips. On a scale of difficult plumbing jobs this one is pretty low down.

 

[Madrab]

Close inspection on the photos reveal the copper pipe is in bad shape showing the signs of rotting and rusting.

I have to say that I can't see any rotting or rusting that's apparent on that, the nut has a bit of a coating but nothing to be concerned about

 

[spader]

OK, thanks for your advice. Will have a go with the replacement job sooner or later.