Circulator pump specifications
1. Maximum operating pressure for the pump must exceed
system operating pressure.
2. Maximum water temperature should not exceed the
nameplate
rating.
3. A properly sized expansion tank must be installed (reference
Section 9 -
Domestic Water Heaters
).
Intermittent pump operation
An intermittent pump operation feature is provided. The water
heater’s circulating pump will cycle on at each call for heat,
before the burner fires. The pump will continue to operate
while the burner is firing. The pump will run for a minimum 30
second period after the temperature set point is satisfied. This
timing is selectable from the Operator Interface. This timing will
remove any of the residual heat from the combustion chamber
before turning the pump off. See the wiring diagram in
Section
11
of this manual.
Pump Maintenance:
Inspect the pump every six (6) months
and oil as necessary. Use SAE 30 non-detergent oil or lubricant
specified by the pump manufacturer.
Low system water volume
System run time is very important to the overall operating
efficiency of the water heater. Short cycling of the water
heater creates problems with condensation in the vent stack,
condensation on the heat exchanger, system temperature spikes,
and mechanical component failures. To prevent short cycling of
the water heater, it is important to limit the water heater cycles
to six or fewer per hour.
4
Water connections
(continued)
33
Installation & Operation Manual
Low temperature bypass requirements
To prevent condensation problems, a water heater MUST NOT
be operated (other than for brief periods during initial system
startup) with an inlet water temperature of less than 140°F
(60°C). If normal system return temperatures are less than
the required 140°F (60°C) water heater inlet requirement, a
method of low return water temperature protection
MUST BE
provided to protect the water heater.
CAUTION
A water heater allowed to operate at set
point temperatures below the specified
minimum settings may experience
operational problems with the operating
controls and safety switches, obstruction of
the flue gas passages on the heat exchanger,
incomplete combustion and possible flue gas
spillage. Operation at lower than specified
water temperatures may cause hazardous
conditions that result in non-warrantable
damage to the appliance.
TABLE - 4A
MAXIMUM FLOW FOR HEATING WATER HEATER
The maximum flow rate through the water heater with a
copper heat exchanger must not exceed the following:
Model
Maximum Flow
500 - 1000
75 GPM
1500 - 2000
90 GPM
If higher flow rates are required through the water heater, an
optional Cupro-Nickel heat exchanger is available. Consult the
factory for specific application requirements.
Minimum water heater inlet temperatures
Inlet water temperatures below the specified minimum of
140°F (60°C) can excessively cool the products of combustion
resulting in condensation on the heat exchanger. Condensation
on the heat exchanger can cause operational problems, bad
combustion, sooting, flue gas spillage and reduced service life
of the related components. See the
Low Temperature Bypass
Requirements
section for water heater system applications
below the minimum specified temperature.
CAUTION
At no time should the system pressure be less
than 12 PSIG.
