Rheem 260 Litre - Manual (Page 25)

CONNECTIONS – PLUMBING
25
RELIEF VALVE DRAIN
A copper drain line must be fitted to the relief valve to carry the discharge clear
of the water heater. Connect the drain line to the relief valve using a
disconnection union. The pipe work from the relief valve to the drain should be
as short as possible and fall all the way from the water heater with no
restrictions. It should have no more than three right angle bends in it. Use
DN20 pipe.
The outlet of the drain line must be in such a position that flow out of the pipe
can be easily seen (refer to AS/NZS 3500.4) - but arranged so hot water
discharge will not cause injury, damage or nuisance. The drain line must
discharge at an outlet or air break not more than 9 metres from the relief valve.
dischargh riofemoppatu thwot un[arotdsek(e)-6.s,in ois