Flowflex are the only manufacturer of a 22mm metric thread (1.1/8″ Whit), which presents a 3/4 inch female screw thread to accept a 3/4 male screw thread.
Why are the fitting and pipe sizes in the world a ‘Dogs Dinner’
The need for this fitting comes about because of metrification which saw push fit and compression plumbing fittings being metricated and screw thread fittings remaining as imperial. To complicate things further, in the UK, and elsewhere in the world, countries saw fit to create new sizes never seen before such as 22mm and 15mm UK, 20mm and 16mm in Australia, New Zealand, and many other countries (including Scicily which is why I am writing this post)
Very few countries saw the merit of following the UK so in export markets for the SPB we find that many countries have kept the old imperial system whilst others have introduced their own sizes in an attempt to follow metrification.
In the UK the original 1/2 inch pipe (15.875mm) was rounded down to 15mm
In most of the world they rounded up to 16mm
In the UK the original 3/4 inch pipes (22.225mm) was rounded down to 22mm.
How to solve this Dogs Dinner of different sizes
The ShowerPowerBooster has the advantage of using the compression system of sealing pipes. The soft brass or copper olives compress and distort to fit to a pipe which is not strictly the right size, or is slightly oval.
1/2 inch (15.875mm) and 15mm metric
We supply all pumps with two 22mm to 15mm 3 piece conversion kits.
Use the kits but for 1/2 inch you simply have to clean the copper pipe and reduce its diameter a very small amount. It might be a tight fit but the olives have a tolerance in them to fit a slightly bigger pipe so you will not have a problem with fitting our ShowerPowerBooster on 1/2 inch pipe.
3/4 inch (22.225) and 22mm
We supply all pumps with two 22mm olives.
Replace the 22mm olive with ’22mm to 3/4 inch conversion olives’ which can be purchased at most local plumbers.
15mm to 16mm
The 22mm Male to 3/4 inch Female Adaptor which is sold by Flowflex will get you to the world of metric fittings and going from 3/4 inch to 16mm with a fitting bought from a local plumbing merchant is highly likely.
If the market was big enough to justify a 3 piece conversion kit for 22mm to 16mm pipe then I am sure such a fitting would be easy to make, and commercially viable. In the UK with no 16mm pipe on the market this seems unlikely but you can adapt the kits we send you.
There is considerable more effort required to reduce the outside diameter of pipe from 16mm to 15mm but it only reduces the pipe wall by 0.5mm so unless you are boosting a high pressure system then reducing the pipe diameter by this amount should not be a problem, but I would not recommend this action.
You have just cut your existing pipe and you are about to insert the Shower Power Booster. Not a good time to start modifying a long length of pipe and if you reduce it too much the olive will not seal on the pipe.
The 3 piece conversion kits are:-
Cone piece – goes in first and has a tapered section which seals against the olive
15 mm olive – seals against the tapered section of the cone piece and the tapered section of the top hat, and the pipe.
Top Hat – has a tapered section which seals against the olive, has a central hole which centralises the pipe. The rim of the top hat seals against the tapered section of the 22mm compression nut.
Before attempting to fit the pumps you need to increase the guide hole of the Top Hat from 15mm to 16mm.
Buy a 16mm compression olive from a local plumbing outlet.
When you finally fit the pumps reduce the diameter of just the pipe below the position of the olive so it can slip into the tapered section as far as the stop.