It probably uses standard coil sizes, so the next one up from the 120
it may be. I can't see DPS using a Part L coil.

They say they use coils in excess of that required by the British Standard,
which is pretty meaningless really. TBH, I don't really care. I'm sure it
should be well overspecced for my storage needs. I'm pretty close to running
two baths simultaneously with a 180L with no regeneration at all. I'm going
to be running the hot water circuit 24/7. I've never run out of hot water
with a 120L gravity indirect cylinder, so I'm not planning to start now.

Christian.