What is the thread out of the top of a hot water cylinder?

[casaco]

I want to fit a sussex flange to a standard hot water cylinder about 10 years old, normally there is a 1inch bsp tapping, this one has a male thread out of the top with a compression 28mm to 22 mm end feed reducer, held in place by a 28mm nut and olive, it does not have a male iron to copper fitting, the threaded bit looks to be screwed directly into the cylinder but if so how can it have a 28mm compression nut to the top if the part that enters the cylinder is 1 inch bsp?

 

[Deleted member 120897]

Do you have a photo? I think some cylinders do have a nut and olive on the outlets.

 

[ShaunCorbs]

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[snowhead]

Do you have a photo? I think some cylinders do have a nut and olive on the outlets.

Like Telford for example

 

[Timmy D]

Out of interest, does the cylinder have a unused secondary return connection on the side?

If you want a air free source for a pump, you can use the secondary.

 

[Ric2013]

Out of interest, does the cylinder have a unused secondary return connection on the side?

If you want a air free source for a pump, you can use the secondary.

Although it wont be 100% air free and unfortunately we have to be as pedantic as the pump manufacturers are in their IOMs if we want them to stand by their products

 

[Timmy D]

Although it wont be 100% air free and unfortunately we have to be as pedantic as the pump manufacturers are in their IOMs if we want them to stand by their products

Good point, check MI’s first.

 

[casaco]

Do you have a photo? I think some cylinders do have a nut and olive on the outlets.

Sorry for the delay, I've been trying to contact the manufacturers.

 

[casaco]

Do you have a photo? I think some cylinders do have a nut and olive on the outlets.

Hi thanks for your reply, just posted some photographs.

 

[Ric2013]

Well, at this point I'd be inclined to buy a 28mm Flowflex brand compression coupling and check its thread against the specifications for 1" BSP. That said, you can already get a vernier onto what you have there to check and, by eye, I have a hunch that that isn't BSP thread (looks too fine).

 

[ShaunCorbs]

It’s 1” as they’ve used a cylinder union

 

[exedon2]

That nut onto cylinder is stamped 28mm so more chance compression? ) castle did make Cylinders with compression connections.

 

[casaco]

Well, at this point I'd be inclined to buy a 28mm Flowflex brand compression coupling and check its thread against the specifications for 1" BSP. That said, you can already get a vernier onto what you have there to check and, by eye, I have a hunch that that isn't BSP thread (looks too fine).

Hi Ric, thanks for replying, I used a vernier gauge already and the pipe out of the cylinder, the od is about 2.5mm larger than the 1inch BSP thread on the Sussex flange od, so definitely not BSP, I think the owner will need a new cylinder as well, I'm not going to try for an Essex flange unless I really have to.

 

[casaco]

That nut onto cylinder is stamped 28mm so more chance compression? ) castle did make Cylinders with compression connections.

Thanks for replying, unfortunately Castle cylinders are now out of business so can't get any info , hence asking you guys.

 

[Ric2013]

Won't the pump manufacturer accept the Mira way of making the connection? (page 16): https://www.mirashowers.co.uk/media/1455/miras-guide-to-pumped-showers.pdf

Then you don't need a flange at all.