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gas supply systems
Low pressure building gas supply systems are defined as those
systems that cannot under any circumstances exceed 14"
W.C. (1/2 PSI Gauge). These systems do not require pressure
regulation. measurements should be taken to insure that gas
pressures are stable and fall within the requirements stated on the
water heater rating plate. readings should be taken with all gas
burning equipment off (static pressure) and with all gas burning
equipment running at maximum rate (dynamic pressure). The
gas supply pressure must be stable within 1.5" W.C. from static
to dynamic pressure to provide good performance. Pressure
drops that exceed 1.5" W.C. may cause rough starting, noisy
combustion or nuisance outages. Increases or spikes in static
pressure during off cycles may cause failure to ignite or in severe
cases damage to appliance gas valves. If your low pressure
system does NOT meet these requirements, the installer is
responsible for the corrections.
High Pressure building supply systems use pressures that
exceed 14" W.C. (1/2 PSI Gauge). These systems must use field
supplied regulators to lower the gas pressure to less than 14"
W.C. (1/2 PSI Gauge). Water heaters require gas regulators that
are properly sized for the water heater input and deliver the rating
plate specified pressures. Gas supply systems where pressure
exceeds 5 PSI often require multiple regulators to achieve desired
pressures. Systems in excess of 5 PSI building pressure should
be designed by gas delivery professionals for best performance.
Water heaters connected to gas supply systems that exceed 14"
W.C. (1/2 PSI Gauge) at any time must be equipped with a gas
supply regulator.
All models require a minimum gas supply pressure of 4.9" W.C.
for natural gas and 11.0" W.C. for propane gas. The minimum
supply pressure is measured while gas is flowing (dynamic
pressure). The supply pressure should never fall below 4.9"
W.C. for natural gas and 10.5" W.C. for propane gas. The supply
pressure should be measured with all gas fired appliances
connected to the common main firing at full capacity. If the supply
pressure drops more than 1.5" W.C. as gas begins to flow to
the water heater then the supply gas system including the gas
line and/or the gas regulator may be restricted or undersized.
See Supply Gas regulator section and Gas Piping section of
this manual. The gas valve on all models has a maximum gas
supply pressure limit of 14" W.C. The maximum supply pressure
is measured while gas is not flowing (static pressure).
14" W.C. The maximum supply pressure is measured while gas
is not flowing (static pressure).
supply gas regulator
The maximum allowable gas supply pressure for this water
heater is 10.5 inches W.C. (2.62 kPa) for natural gas and 14.0
inches W.C. (3.49 kPa) for propane. Install a positive lock-up gas
pressure regulator in the gas supply line if inlet gas pressure can
exceed these pressures at any time.
If a positive lock-up regulator is required follow these instructions:
installation reQuirements
1.
Positive lock-up gas pressure regulators must be rated at or
above the input Btu/hr rating of the water heater they supply.
2.
Supply gas regulators shall have inlet and outlet connections
not less than the minimum supply gas line size for the water
heater they supply. See Table 8, page 23.
3.
Positive lock-up gas pressure regulator(s) should be installed
no closer than 3 feet (1 meter) and no farther than 8 feet (2.4
meters) from the water heater's inlet gas connection.
4.
After installing the positive lock-up gas pressure regulator(s)
an initial nominal supply pressure setting of 7.0" W.C. while the
water heater is operating is recommended and will generally
provide good water heater operation. Some addition adjustment
maybe required later to maintain a steady gas supply pressure.
5.
When installing multiple water heaters in the same gas
supply system it is recommended that individual positive
lock-up gas pressure regulators be installed at each unit
from the supply gas connection on the water heater.
power supply
The water heaters covered in this manual require a 120 VAC,
1Ø (single phase), 60Hz, 15 amp power supply and must also
be electrically grounded in accordance with local codes or, in the
absence of local codes, with the National Electrical Code, ANSI/
NFPA 70 or the Canadian Electrical Code, CSA C22.1.
power fluctuations and electrical noise
The water heater's control system requires a source of stable
clean electricity for proper operation. Connecting the water heater
to a branch circuit that is subject to fluctuations in voltage level or
electrical line noise such as EmI (electro magnetic interference)
or rFI (radio frequency interference) may cause erratic control
system operation and malfunction.
A high quality power supply filter/suppressor such as the Kleen Line
model SELF/T-10 Series SC-L or equivalent must be installed if the
above conditions exist. Call the technical support phone number
listed on the back cover of this manual for more information.
note: malfunctions caused by the power supply and the costs to
install power supply filters are not covered under the limited warranty.
dedicated power wiring and Breakers
Dedicated power supply wires, ground wiring and dedicated
circuit breakers often prevent electrical line noise and should be
considered when installing the water heater.
polarity sensitiVe
The control system on the water heaters covered in this manual
is polarity sensitive; electronic flame sensing requires correct
polarity. The control system is programmed to monitor the
incoming power supply. If the Hot and Neutral wires in the 120
VAC power supply are reversed, the control system will declare
a Fault condition and lock out, heating operation will be disabled
until the power supply is correctly wired. The control system will
display the "AC reversed" Fault message on the LCD.
See Electrical Wiring on page 41 for installation instructions.
14
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