Rheem RTG-3 Series Use And Care Manual page 36

INSTALLATION INSTRUCTIONS
Water Supply
Recirculation
Direct recirculation is allowed, provided the loop
is thermostatically controlled, and a timer is used
to turn the pump off during off peak periods. The
pump must be sized for a minimum of 5 gpm at
25 ft of head plus building head. A 10°F difference
between the loop thermostat setting and water
heater temperature setting must be maintained.
To ensure proper operation of the water heater,
follow these water pressure guidelines.
Operation of the water heater requires a minimum
water pressure of 14 psi (97 kPa) and a minimum
activation water flow rate of 0.4 gpm (1.5 lpm).
Continuous operation of the water heater requires
a minimum water flow rate of 0.25 gpm (1.01 lpm).
Water pressure of 40 psi (276 kPa) is required to
achieve maximum flow rate.
To maintain proper performance, there must be
sufficient water supply pressure.
Water Supply Installation
NOTICE:
• Use only Teflon tape on all COLD and HOT water
connections.
• If the water flow resistance of a showerhead is
too high, the burner in the water heater will fail
to ignite. Keep all showerheads clean from debris
that could cause additional pressure drop.
• If using mixing valves on the outlet, choose
one that prevents COLD water pressure from
overcoming HOT water pressure.
• If multiple water heaters are installed in a
manifold system, the water piping MUST be in
"parallel" and the water pressure at each water
heater should be 40 psi (276 kPa).
1
Install a COLD water shut-off valve near the inlet
line on the water heater. This valve will be used for
servicing and draining purposes.
36
Required Water Pressure =
Min. Operating Water Pressure
(14 psi [97 kPa])
+ Pipe Pressure Loss
+ Faucet Pressure Loss
+ Safety Margin
(more than 5 psi [34 kPa]).
To supply HOT water to upper floors, additional
water pressure will be required (0.44 psi [3 kPa]
per foot of height). Calculate the distance between
the water inlet of the water heater (ground level) to
the HOT water faucet farthest away from the water
heater (upper floor level).
• Well water systems should be set to ensure a
minimum system pressure of 40 psi (276 kPa).
The pressure should remain constant and stable
during the operation of the water heater.
• Gravity water pressure is not recommended.
When the water is supplied from a water supply
tank, the height of the tank, the diameter of the
supply pipes, and their relation to water pressure
need to be taken into consideration.
NOTICE:
It is not recommended to use pipes with smaller
diameters than the water supply connection of the
water heater.
2
Before attaching the water line to the water heater,
open the shut-off valve. Run the water until it
has purged all contaminants (sand, debris, air,
caulking).
3
Install a service valve on the end of the COLD
water supply line and connect it to the water inlet
on the water heater.