Seems to address the concern that water or sediment would be sitting long term on the valve. The coil is interesting. Required, or just what this plumber used? Periodic testing of the T&P valve would need to include making sure that water was making it thru the coil.nspected and approved by AJH under IAMPO. In operation.
The up leg goes up about 3 feet, then gently slopes to the outside.
The pigtail goes down to the tray.
This is now a standard prescriptive design, anyone can use in my region.
I assume there is a threaded joint/ union, hidden by the insulation in the photo, that makes changing the T&P practical.