When a 1" connection doesn't quite fit

zagmund

I have a large water tank with a 1" connection at the bottom for draining. In normal use it is pumped via a different route and this 1" isn't used. All my normal garden hose stuff is 3/4" or 1/2" so I went to Woodies and got what looked (to me) like just the thing I needed, but it doesn't fit. It's described as '1" x 3/4" F.I x C elbow coupling.' The tank end is a 1" connection, the other end is 3/4".

Unfortunately neither end fits - the 1" threading on the elbow doesn't match with the 1" threading on the drain from the tank. Similarly, the 3/4" threading doesn't match the screw on fitting that fits my garden tap. The 1" connection is just threaded, the 3/4" one has a brass ring inside, but I was hoping to just go with the threads and screw the fitting on.

They both look to be *almost* the correct size and almost screw on, but they just don't engage. The only other text on the packing says it's a compression fitting, but I'm not sure exactly what this is telling me.

Have I bought the wrong thing? While it's possible that the 1" fitting on the drain is non-standard, I would have thought that a 3/4" connection that fits my garden tap should fit anything else of a similar vein in the plumbing world which is marked as 3/4", but it seems not.

In short - is compression fitting the wrong thing for this? If not compression, what other sort of 1" to 3/4" thing should I be asking for in the shops?

I'm not the worlds best DIY'er but I'm reasonably competent once I know what I'm looking for so thanks for any pointers.

Thanks,

z

jeepers101

zagmund wrote: »

I have a large water tank with a 1" connection at the bottom for draining. In normal use it is pumped via a different route and this 1" isn't used. All my normal garden hose stuff is 3/4" or 1/2" so I went to Woodies and got what looked (to me) like just the thing I needed, but it doesn't fit. It's described as '1" x 3/4" F.I x C elbow coupling.' The tank end is a 1" connection, the other end is 3/4".

Unfortunately neither end fits - the 1" threading on the elbow doesn't match with the 1" threading on the drain from the tank. Similarly, the 3/4" threading doesn't match the screw on fitting that fits my garden tap. The 1" connection is just threaded, the 3/4" one has a brass ring inside, but I was hoping to just go with the threads and screw the fitting on.

They both look to be *almost* the correct size and almost screw on, but they just don't engage. The only other text on the packing says it's a compression fitting, but I'm not sure exactly what this is telling me.

Have I bought the wrong thing? While it's possible that the 1" fitting on the drain is non-standard, I would have thought that a 3/4" connection that fits my garden tap should fit anything else of a similar vein in the plumbing world which is marked as 3/4", but it seems not.

In short - is compression fitting the wrong thing for this? If not compression, what other sort of 1" to 3/4" thing should I be asking for in the shops?

I'm not the worlds best DIY'er but I'm reasonably competent once I know what I'm looking for so thanks for any pointers.

Thanks,

z

Pics please

sky6

What you have is a GB Thread and you're trying to connect instantor fittings to it. They look very similar but are different threads and won't fit. The good news is you can get an adapter to go from one to the other and vice versa.
Best option is to go to a proper plumbing supplier who will immediately know of the problem and be able to sort you out with the right fittings or adaptors.

zagmund

Photos attached.

Since the garden tap fitting doesn't fit the elbow, does this point to the elbow being the problem?

z

K.Flyer

Did you disconnect something from the fitting in pic 2 and what are you trying to connect to it now?
Can you show a picture of what was connected?

zagmund

K.Flyer - nope, there was nothing attached originally. I've included pictures for context. It's located at the bottom of a 500 (I think) litre water tank. There's a red valve handle keeping it closed, and the original fitting on the tank is marked 1 1/4". The guy who fitted it originally probably put on the elbow which brought it down to 1" (almost).

My overall aim is to be able to connect a garden hose to it, to allow me to occasionally use the water. The normal model is that it is pumped up to the attic and then gravity fed to the toilets and outside tap. My aim here is just to avoid pumping the gardening water up since it's not necessary for this purpose - the tank is already a good bit (probably 1 or 2 metres) above the garden level, so gravity should suffice. Water for the toilets would continue to be pumped as normal.

I thought that in this case what I needed was a 1" to 3/4" adapter, but as I've found out, they aren't all the same.

z

Robbie.G

zagmund wrote: »

K.Flyer - nope, there was nothing attached originally. I've included pictures for context. It's located at the bottom of a 500 (I think) litre water tank. There's a red valve handle keeping it closed, and the original fitting on the tank is marked 1 1/4". The guy who fitted it originally probably put on the elbow which brought it down to 1" (almost).
My overall aim is to be able to connect a garden hose to it, to allow me to occasionally use the water. The normal model is that it is pumped up to the attic and then gravity fed to the toilets and outside tap. My aim here is just to avoid pumping the gardening water up since it's not necessary for this purpose - the tank is already a good bit (probably 1 or 2 metres) above the garden level, so gravity should suffice. Water for the toilets would continue to be pumped as normal.

I thought that in this case what I needed was a 1" to 3/4" adapter, but as I've found out, they aren't all the same.

z

Was that tank used for oil if so it's not suitable as no matter how much you try and clean it you won't get it clean.
What your looking for is a 3/4 311 screw that into the new fitting and place a small piece of copper between.
That is of course once it's 3/4 it's very hard to tell from pics

zagmund

Robbie.G -> nope, it has only ever been used for water, it was bought new for that purpose. The new fitting doesn't work at all for me - either end. Are you saying that the tank connection is 311? and I need a 311 to match it, or the new brass fitting is 311? I can change/replace the new one rather than try to bodge something onto it.

Thanks,

z

K.Flyer

zagmund wrote: »

...

the original fitting on the tank is marked 1 1/4". The guy who fitted it originally probably put on the elbow which brought it down to 1" (almost).
....
I thought that in this case what I needed was a 1" to 3/4" adapter, but as I've found out, they aren't all the same.

z

First you need a 1" compression nut and ring.
A short length of 1" copper pipe.
A 1" - 3/4" c.mi. 311 (1" nut ring 3/4" male thread)
Some ptfe tape.

Assemble the 311 onto the pipe while putting a couple of wraps if ptfe tape around the ring and tighten up tight using tools.
Put the pipe into the elbow fitting off the tank valve and tighten on using the 1" nut and ring, again putting a couple of wraps of ptfe on the ring first and tighten up using tools.
The 3/4" male thread will then take your hose fittings.

That assembly will bring you straight out off the elbow off the valve.