Rheem 551180 Owner's Manual And Installation Instructions page 37

PIPE SIZES
To achieve true mains pressure operation, the cold water line to the water heater should be the same size or
bigger than the hot water line from the water heater.
The pipe sizing for hot water supply systems should be carried out by persons competent to do so, choosing
the most suitable pipe size for each individual application. Reference to the technical specifications of the
water heater and local regulatory authority requirements must be made.
TEMPERATURE PRESSURE RELIEF VALVE
The temperature pressure relief valve is shipped with the water heater. The temperature pressure relief valve
must be fitted before the water heater is operated. Before fitting the relief valve, make sure the probe has not
been bent.
To fit the relief valve:
•
Seal the thread with an approved thread sealant such as Teflon tape - never hemp. Make sure tape
does not hang over the end of the thread.
•
Hand tighten the valve into the opening marked "Relief Valve".
Refer to the dimensions diagram
•
Using a spanner engaged on the valve's spanner flats and applying medium pressure to tighten, turn the
relief valve an additional ½ to 1 ½ turns to secure and make the joint watertight, leaving the valve drain
pointing downwards.
Warning: Do not use a pipe wrench or poor fitting tool on the valve body nor over tighten the valve,
as this could damage the valve and prevent safe operation.
•
Operate the easing lever on the valve to check the smooth operation of the valve plunger. It is very
important the lever is raised and lowered gently. The lever should move smoothly and without undue
force.
•
If the lever cannot be moved or is jerky in its movement, then the valve has been damaged and must be
replaced.
•
A copper drain line must be fitted to the temperature pressure relief valve.
Refer to "Relief Valve Drain"
•
The valve must be insulated with closed cell polymer insulation or similar (minimum thickness 9 mm)
and the insulation installed so as not to impede the operation of the valve.
The insulation must be weatherproof and UV resistant if exposed.
EXPANSION CONTROL VALVE
In South Australia, Western Australia and New Zealand, it is mandatory to install an expansion control valve
(ECV) in the cold water line to the water heater. In other areas, an ECV is required if the saturation index is
greater than +0.4. Refer to
The expansion control valve must always be installed after the non-return valve and be the last valve
installed prior to the water heater. Refer to the
expansion control valve. Refer to
The valve, if installed within 500 mm of the water heater, must be insulated with closed cell polymer
insulation or similar (minimum thickness 9 mm) and the insulation installed so as not to impede the operation
of the valve. The insulation must be weatherproof and UV resistant if exposed.
on page 33.
on page 38.
"Water Supplies"
on page 22.
diagram
"Relief Valve Drain"
on page 36. A copper drain line must be fitted to the
on page 38.
37
CONNECTIONS – PLUMBING