I've moved into a new home and the existing hot water system is 'strange'.
It's a direct cylinder but has been 'converted' to indirect (using the direct cylinder).
The direct feed boiler water connections have been capped off, and an indirect 15mm feed from the boiler (fully pumped) goes into the cylinder where the immersion should be as a sort of heating coil. However, the 'coil' must only be short as only the top 1/5th of the tank gets warm(!).
So I'm going to replace the cylinder with a more modern one, with a much more efficient coil (like the centercyl or similar).
My question is : Is it acceptable to use the existing 15mm pipes from the boiler via adaptors to the 1" coil connections on the new cylinder, or should I replace the boiler pipes with 22mm. The existing system works OK with regards to the pumping of the water so I'm guessing that 15mm would be ok but as I'm an electrician, not a plumber, I'd like a bit of advice about this.
Thanks in advance.