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Verifying system heating, Verifying & adjusting temperature rise, Gas supply pressure verification & adjustment – Reznor R8HE Unit Installation Manual User Manual

Page 19: Verifying the firing rate of the appliance, Of the appliance section on, Warning

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19

1. Turn ON the manual gas valve, located on the outside

of the unit to the ON position.

2. Check all gas connections for leaks with a soap and

water solution. If the solution bubbles there is a gas leak

which must be corrected.

3. Turn on the electrical power to the appliance.

4. Place the gas valve ON/OFF switch to the ON position.

See

Figure 7 (page 20)

.

5. Set the thermostat above room temperature to begin

the heating cycle of the furnace.

6. Check that the furnace ignites and operates properly.

7. After ignition, visually inspect the burner assembly to

ensure that the flame is drawn directly into the center of

the heat exchanger tube. In a properly adjusted burner

assembly, the flame color should be blue with some light

yellow streaks near the outer portions of the flame.

NOTE: The ignitor may not ignite the gas until all air is

bled from the gas line. If the ignition control locks out,

turn the thermostat to its lowest setting and wait one

minute then turn the thermostat above room temperature

and the ignitor will try again to ignite the main burners.

This process may have to be repeated several times

before the burners will ignite. After the burners are lit,

check all gas connections for leaks again with the soap

and water solution.

Verifying System Heating
(2-Stage Heating)

1. Set the thermostat to the lowest setting.

2. Follow the procedures given on the operating instruction

label, in this manual or attached inside the louvered

control access panel.

3. Set the thermostat one degree above room temperature

and verify the Operating Sequence (

page 21

).

4. Verify that the compressor and outdoor fan motor are

not energized.

5. After determining the system is running (1-2 minutes),

raise the thermostat’s setpoint an additional 3-4 degrees

until the heating system moves into 2nd stage or high

heat operating mode. The gas valve will energize to high

heat mode while the induced draft motor and indoor

blower motor both increase in speed.

6. After the unit has run for approximately five minutes,

set the thermostat below room temperature and verify

the shutdown sequence; steps 10 -12 in the Operating
Sequence section (

page 21

).

Verifying & Adjusting Temperature Rise

Verify the temperature rise through the unit is within the

range specified on the unit data label. Temperature rises

outside the specified range could result in premature heat

exchanger failure.
1. Place thermometers in the return and supply air stream

as close to the unit as possible. The thermometer on the

supply air side must be shielded against direct radiation

from the heat exchanger to avoid false readings.

2. Adjust all registers and duct dampers to the desired

position. Run the unit for 10 to 15 minutes before

taking any temperature readings. The temperature

rise is the difference between the supply and return air

temperatures.

NOTE: For typical duct systems, the temperature rise will

fall within the range specified on the data label (with the

blower speed at the factory recommended setting) see
in

Table 8 (page 28)

,

Table 9 (page 28)

,

Table 10

(page 29)

,

Table 11 (page 30)

,

Table 12 (page 31)

&

Table 13 (page 32)

. If the measured temperature rise

falls outside the specified range, it may be necessary to

change the blower speed. Lowering the blower speed

increases the temperature rise and a higher speed

decreases the temperature rise.
The unit is equipped with an ECM type motors. Speed

selection is made by setting the switches on the motor
control board. See

Figure 11 (page 36)

.

NOTE: For

change in blower speed selection to take effect, system

power must be cycled off then restored after 10 seconds.
Refer to the Blower Speed section (

page 13

) for

additional information.
The integrated control starts the circulating air blower 22

seconds after the gas valve is opened. The control board

is factory set to turn the blower motor off 120 seconds

after the gas valve is closed.

Gas Supply Pressure Verification &
Adjustment

1. Turn OFF the gas supply at the manual valve located

on the outside of the unit.

2. Using a 3/16” Allen wrench, remove the plug from the

inlet pressure tap (INLET side of gas valve). See

Figure

7 (page 20)

.

3. Install an 1/8” NPT pipe thread fitting, that is compatible

with a Manometer or similar pressure gauge.

4. Connect the Manometer or pressure gauge to the Inlet

Pressure Tap.

5. Turn ON the main gas supply at the manual valve.

6. Check and adjust the incoming gas line pressure to 4.5-

10.0 inches Water Column for Natural gas or 11.0-14.0

inches Water Column if converting unit to LP/Propane

gas.

7. Turn OFF the gas supply at the manual valve.

8. Disconnect the Manometer or pressure gauge.

9. Remove the NPT fitting and reinstall the INLET pressure

tap plug. Hand tighten the plug first to prevent cross

threading. Tighten with 3/16 Allen wrench.

Verifying the Firing Rate of the Appliance

WARNING:

Do not attempt to drill the gas orifices. If the orifice

size must be changed, use only factory supplied

orifices. Improperly drilled orifices may cause fire,

explosion, carbon monoxide poisoning, personal

injury or death.

The firing rate must be verified for both LOW and HIGH

fire for each installation to prevent over-firing of the unit.

The firing rate must not exceed the rate shown on the