Install Instructions

56
CHECKING THE FIRING RATE
If ring rate adjustment is required follow these instructions to
determine the actual ring rate of the water heater:
NOTE: The heaters covered by this manual are capable of
modulating their ring rate. The ring rate should be checked
with the heater operating at it's full ring rate.
1. Ensure there are no other gas red appliances connected to
the gas meter ring during this test.
2. Contact the gas supplier to determine the heating value, in
Btu per cubic foot, of the gas supply.
3. Connect a manometer to the supply gas pressure tap. Follow
the instructions for Initial Start Up on page 53.
4. Start the water heater and ensure it is ring.
5. Check the supply gas pressure, refer to Table 3 on page
11 for correct pressure.
6. Locate the gas meter serving the water heater.
7. Time how long (in seconds) it takes for one cubic foot of gas
to be used while the water heater is ring with a stop watch.
8. Use the formula below to “clock” the gas meter and determine
the actual ring rate of the water heater based on the heating
value (Btu per cubic foot) of the gas supply:
x H = Btu/hr
3600
T
x 1050 = 300,000 Btu/hr (87.9 kW)
3600
12.6
Example:
• 3600 = seconds in one hour.
• T = time, in seconds, to burn one cubic foot of gas.
• H = heating value of gas in Btu per cubic foot.
• Btu/hr = actual ring rate of the water heater.
NOTE: 1050 Btu per cubic foot is a standard value for
natural gas. Standard propane gas Btu content is 2500
Btu per cubic foot. Btu values may change in certain
areas and at high elevations. Check with the local gas
utility company.
TO TURN OFF GAS
1. Change the Operating Set Point to the lowest temperature
setting, see Operating Set Point And Differential Adjustment
on page 48.
2. When the water heater has completed its shut down sequence
and enters the standby mode, turn the water heater’s on/off
switch to the “off” position.
3. Close Main Gas Shutoff Valve, see Figure 54 on page 40.
HIGH ALTITUDE INSTALLATIONS
Fire and Explosion Hazard
Gas and carbon monoxide detectors are
available.
Overfiring could result in fire or
explosion.
Under no circumstances should the
input exceed the rate shown on the
water heater’s rating label.
Breathing Hazard - Carbon Monoxide Gas
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Under no circumstances should
the input exceed the rate shown
on the water heater’s rating label.
Overfiring could result in damage to
the water heater and sooting.
Gas and carbon monoxide detectors
are available.
The heater models covered by this manual are certied for use
without modication for altitudes up to 10,100 feet (3,078 m).
Most gas utility companies de-rate their gas for high altitudes,
making it unnecessary to install high altitude orices.
For installations above the certied elevations listed above
call the technical support phone number listed on the back
cover of this manual for further technical assistance. Call
the local gas or utility company to verify Btu per cubic foot
content before calling for technical assistance and have that
information available.
NOTE: The actual ring rate of the water heater must not
exceed the input rating on the water heater's rating label
under any circumstances.
NOTE: Due to the input rating reduction at high altitudes, the
output rating of the water heater is also reduced and should
be compensated for in the sizing of the equipment.