Cold Water Run; Purpose; Typical Cold Water Run Applications; Cwr Vs. Cws - Rheem Raypak Hi Delta 302C Installation And Operation Manual

5. COLD WATER RUN

NOTE: After testing at the factory it may be prudent to
ship the piping assembly disassembled and attached to
the heater pallet. This is done to avoid shipping damage
and it must be reassembled on the jobsite. Use Figure 21
to assist you in reassembling the piping.

Purpose

The Cold Water Run system utilizes a variable-speed
pump to inject the proper amount of water from the main
system loop into the heater to maintain the optimum inlet
temperature. This approach allows the full capacity of the
heater to be utilized to meet the system load, while at the
same time continuously maintaining the optimum inlet
water temperature to prevent condensation.

Typical Cold Water Run Applications

• Swimming pools.
• Any system with steady-state (or "consistent") return
water temperature below 105°F (40.5ºC).

CWR vs. CWS

• Cold water start is for transient cold water operation.
• Cold water run is for continuous operation below
105°F (40.5ºC) system return temperature.
• Cold water start maintains design flow rate at system
design temperature but reduces boiler flow rate
during heavy bypass operation.
• Cold water run maintains constant design flow rate
in the boiler.

Installation

Before beginning the installation, it's important to first
inspect the system and determine what materials you will
need. Some parts are included with the controller while
others you will need to provide.

Installation Codes

Installations must be in accordance with local, state,
provincial, and national codes, laws, regulations and
ordinances. In the absence of local codes, installations
must be in accordance with the latest editions of the:
• National Fuel Gas Code, ANSI Z223.1/NFPA 54
• National Electrical Code, ANSI/NFPA 70
• For Canada only: CAN/CSA B149 Installation Code
and CSA C22.1 C.E.C. Part 1 and Part 2
20
TO SYSTEM
RAYTHERM MODELS
2100 TO 4001 ONLY
HEATER
Figure 21. Cold Water Run Assembly

Mounting the Control Box

NOTE: The heater should not be located in an area
where possible water leakage will result in damage to
the area adjacent to the heater or to the structure. When
such locations cannot be avoided, it is recommended
that a suitable drain pan, with adequate drainage, be
installed under the heater. The pan must not restrict
combustion air flow.
The control box should be mounted on the side of the heater
to which the system piping and pump assemblies are to
be attached as shown in Figure 4 through Figure 8. The
controller should be mounted so as to provide maximum
support by using the mounting holes provided on the base
of the controller to the side center brace on the heater. You
will need to drill mounting holes for #10 hardware and 3/4"
conduit access holes through the heater side panel for the
routing of wiring and the sensor.
CAUTION:
Remote-mounted
installed within 25 feet (7.6 m) of wire length to the heater.
FROM SYSTEM
COLD WATER RUN
INJECTOR PUMP
HEAT
CIRCULATING
PUMP
COLD WATER RUN ASSEMBLY
INSTALLED CONFIGURATION
controller must be