I have a customer whose hot water is too hot. He has a 15 yr old Copperform indirect foam insulated grade III copper cylinder.
Cylinder stat can be set at 50 deg, but it's still steaming. At around 70-75 degs.
We've done all the normal things like checking the 3 port valve, changing the cyl stat. But it was still getting too hot.
So out of desparation I moved the stat halfway up the cylinder - no change.
Finally, I checked the temperature up against the bare copper surface in the cylinder stat aperture - lukewarm. Same story for the old cylinder stat aperture. But when you draw water off, and there is plenty of it, it is around 75 deg C.
The only conclusion I can make is that there is a great deal of scale on the inside faces of the cylinder preventing heat transfer to the shell. Normally I'd expect this to be in the bottom and on the primary coil, rather than the circumference.
Any ideas, I haven't seen this before?
Cylinder stat can be set at 50 deg, but it's still steaming. At around 70-75 degs.
We've done all the normal things like checking the 3 port valve, changing the cyl stat. But it was still getting too hot.
So out of desparation I moved the stat halfway up the cylinder - no change.
Finally, I checked the temperature up against the bare copper surface in the cylinder stat aperture - lukewarm. Same story for the old cylinder stat aperture. But when you draw water off, and there is plenty of it, it is around 75 deg C.
The only conclusion I can make is that there is a great deal of scale on the inside faces of the cylinder preventing heat transfer to the shell. Normally I'd expect this to be in the bottom and on the primary coil, rather than the circumference.
Any ideas, I haven't seen this before?