Identifying Unvented Copper Cylinder

[amwater]

Recently I was asked by a customer to quote for removing a boiler and unvented cylinder from an upstairs bedroom and re-locating them in the basement. While inspecting the existing installation I noticed the copper cylinder didn't have an external expansion vessel. I assumed it must have an internal air-bubble with floating baffle, however I can't find any similar copper cylinders on the market with internal expansion, they're all stainless steel. Do copper cylinders exist with internal expansion? If not, how has the cylinder managed to survive for the last 15 years? The mains pressure is about 2 bar and the PRV is set at 1.8 bar.

 

[finkbat]

The way to find out for certain (if there's no obvious indication) would be to drain it down to the level of the TPRV, then fill it up again and see how long it takes for water to come out of the hot. If it is internal air gap then this would be quite quick as the water level would be up to the internal dip-tube which is a similar height as the TPRV. If it takes a long time then it's external.

When drained down can you take the immersion out and look inside?

If the TPRV is high up (very near the top), then I would suggest it's not internal air gap.

Any chance of a photo?

 

[townfanjon]

The very first Tribunes were all copper and internal expansion, and 2.1 set PRV, it may have survived because it was serviced .
They weigh -in for a fortune.

 

[BLOD]

The very early tribines had a solid non moving mushroom shaped thing made from copper to aid expansion. From the ones I came across they never really worked but as townfanjon says good returns at the scrappie.

 

[amwater]

Thanks for the tips. The TPRV is about 3/4 the way up just below where the cylinder starts to dome. I'll try and get a photo.

 

[amwater]

It may well be a Tribune. On the net I found a manual from 1994. The Honeywell motorised valve and cylinder stat supplied with the unit look the same. Thanks

 

[Chalked]

Got one in my house!