Making ( pipe) connections
My boat is fitted with central heating and I want to replace the 15mm main pipe runs with 22mm poly piping. Have you any suggestions on how best to connect the 22mm pipe to the rubber heater hose from the MX40, the rubber hose is 16mm?
Polypipe make a hose connection but say it is not suitable for central heating (house domestic I assume) but the fitting looks to be the same
QAPlastic pipe reinforcing inserts tend to be unreliable where compression fittings are used on poly pipe. This may well apply at the radiator connections. If it does, my advice would be to buy metal inserts from a proper plumbers’ merchant.
If you can find a metal barbed hose connector with a suitable-sized female thread, I think a poly tap connector would do the job ( Screwfix 64549 and similar).
If you cannot find such a hose connector then you can solder a 15mm Yorkshire straight connector to a short length of 15mm pipe. The bumps on the outside of the Yorkshire fitting act as barbs so the hose cannot work its way off once clipped and it provides strength so the hose clip cannot deform it.
I think poly fittings also work with copper pipe, so a female 15 to 22mm coupler should do the job. If all else fails, you could use a compression coupler with metal reinforcing insert in the plastic pipe..