Checking the firing rate, High altitude installations – State Industries ULTRA FORCE 101 User Manual

Page 55

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55

checking the firing rate

if firing rate adjustment is required follow these instructions to

determine the actual firing rate of the water heater:
1. Ensure there are no other gas fired appliances connected to

the gas meter firing 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 manifold gas pressure tap.

Follow the instructions for initial Start Up on page 52.

4. Start the water heater and ensure it is firing.
5. Check the manifold gas pressure, refer to Table 3 on page

12 for correct pressure. See manifold Gas Pressure

Adjustment on page 54 if adjustment is necessary.

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 firing with a stop watch.

8. Use the formula below to “clock” the gas meter and determine

the actual firing 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 firing 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 47.

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 the main Gas Shutoff Valve, see Figure 52 on page 39.

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.

SUF 100 120 and SUF 100 150 models are certified for use

without modification for altitudes up to 7,700 feet (2,347 m).
SUF 100 199 and SUF 100 250 models are certified for use

without modification 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 orifices.
For installations above the certified 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 firing 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 for applications.

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