Plumbing Applications; Recirculation System - Noritz NRC98-OD Installation Manual

11.

Plumbing Applications

NORITZ
Condensing
Tankless Gas
Water Heater
Isolation
Kit(*4)
Relay for Pump
(if larger than 85 Watts)
Hot Water
Combination Potable Water and Space Heating System
NORITZ
Condensing
Tankless Gas
Water Heater
Isolation
Kit(*1)
18

Recirculation System

Cold Water Supply
Fixtures
Expansion Tank
(Install according
to local code)
Gas Supply
Globe
Aquastat(*3)
Valve
Pump Control Signal(*2)
Optional 8-10 Gallon
Storage Tank
(To alleviate cold water sandwich)
Pump(*2)
Check
Valve(*3)
Gas Supply
Hot Water
Notes:
1. Size the pump to provide a maximum of 2 GPM
(7.5 L/min.) through the system at 10 ft (3m) of
head plus piping losses.
Hot Water Return
Adjust the flow using a globe valve and verify the
flow rate with the maintenance monitors.
2. Pump Control Signal is the preferred method to
control the recirculation pump.
For pumps larger than 85W, a relay connection
must be used. If the Pump Control Signal is not used,
an Aquastat may be used to control the pump.
3. Use an Aquastat if the water heater is not control-
ling the pump.
Set the Aquastat to 10°F (5°C) below the set
output temperature.
4. Noritz recommends the use of an Isolation Kit with
the installation.
These kits include an integrated shut-off and service
valve with unions and a pressure relief valve.
Pump(*1)
Notes:
1. Noritz recommends the use of an Isolation Kit with
the installation.
These kits include an integrated shut-off and service
valve with unions and a pressure relief valve.
2. Size the pump to provide a maximum of 3 GPM
Air Handler
(11.3 L/min.) with a head pressure equal to the loss
through the water heater and Air Handler.
3. Check valve required if it is not included with the pump.
4. Set the flow switch to deactivate the Air Handler when
the domestic hot water flow reaches 3 GPM (11.3 L/min.).
Adjust as necessary to prevent cycling.
5. If the system requires water for space heating at a higher
temperature than for other uses, means such as a
mixing valve shall be provided to temper the water for
the other uses to help prevent scalding.
6. Expansion tank required if a backflow preventer is installed.
7. The water heater cannot be used for space heating
applications only.
Flow Switch(*4)
Optional
Expansion Tank(*6)
Mixing Valve(*5)
105
Pump
R
120VAC
B
S
W
Neutral
Ground
Live
Aquastat Wiring
Use Honeywell Aquastat
(Model L6006A or L6006C)
Backflow Preventer
(optional)
Cold Water
Supply
Fixtures