6.Turn ON power and close thermostat “R” and “W” contacts to provide a call for heat.
7.Using a leak detection solution or soap suds, check for leaks at outlet pressure boss plug (Honeywell valve) or screw (White-Rodgers valve). Bubbles forming indicate a leak. SHUT OFF GAS AND REPAIR ALL LEAKS IMMEDIATELY!
8.Measure the gas manifold pressure with burners firing. Adjust manifold pressure using the Manifold Gas Pressure table shown below.
Manifold Gas Pressure
Natural Gas | 3.5" w.c. |
Propane Gas | 10.0" w.c. |
9.Remove regulator cover screw from the outlet pressure regulator and turn screw clockwise to increase pressure or counterclockwise to decrease pressure. Replace regulator cover screw.
10.Turn OFF all electrical power and gas supply to the system.
11.Remove the manometer hose from the hose barb fitting or outlet pressure boss.
12.Replace outlet pressure tap:
a.Honeywell VR8215 valve:
Remove the 1/8” NPT hose barb fitting from the outlet pressure tap. Replace the outlet pressure boss plug and seal with a high quality thread sealer.
b.White-Rodgers 36G22 valve: Turn outlet pressure test screw in to seal pressure port (clockwise, 7 in-lb minimum).
13.Turn ON electrical power and gas supply to the system.
14.Close thermostat contacts to provide a call for heat.
15.Retest for leaks. If bubbles form, SHUT OFF GAS AND REPAIR ALL LEAKS IMMEDIATELY!
Gas Input (Natural Gas Only) Check
To measure the gas input use a gas meter and proceed as follows:
1.Turn off gas supply to all other appliances except the unit.
2.With the unit operating, time the smallest dial on the meter for one complete revolution. If this is a 2 cubic foot dial, divide the seconds by 2; if it is a 1 cubic foot dial, use the seconds as is. This gives the seconds per cubic foot of gas being delivered to the unit.
3.INPUT=GAS HTG VALUE x 3600 / SEC. PER CUBIC FOOT Example: Natural gas with a heating value of 1000 BTU per cubic foot and 34 seconds per cubic foot as determined by Step 2, then:
Input = 1000 x 3600 / 34 = 106,000 BTU per Hour. NOTE: BTU content of the gas should be obtained from the gas supplier. This measured input must not be greater than shown on the unit rating plate.
4.Relight all other appliances turned off in step 1. Be sure all pilot burners are operating.
Main Burner Flame Check
Flames should be stable, soft and blue (dust may cause orange tips but they must not be yellow) and extending directly outward from the burner without curling, floating or lifting off.
Temperature Rise Check
Check the temperature rise through the unit by placing thermometers in supply and return air registers as close to the unit as possible. Thermometers must not be able to sample temperature directly from the unit heat exchangers, or false readings could be obtained.
1.All registers must be open; all duct dampers must be in their final (fully or partially open) position and the unit operated for 15 minutes before taking readings.
2.The temperature rise must be within the range specified on the rating plate.
NOTE: Air temperature rise is the temperature difference between supply and return air.
With a properly designed system, the proper amount of temperature rise will normally be obtained when the unit is operated at rated input with the recommended blower speed.
If the correct amount of temperature rise is not obtained, it may be necessary to change the blower speed. A higher blower speed will lower the temperature rise. A slower blower speed will increase the temperature rise.
NOTE: Blower speed MUST be set to give the correct air tempera- ture rise through the unit as marked on the rating plate.
External Static Pressure Check
The total external static pressure must be checked on this unit to determine if the airflow is proper.
Blower Speed Adjustments
WARNING
TO AVOID PERSONAL INJURY OR DEATH DUE TO ELECTRIC SHOCK, REMOVE ELECTRICAL POWER FROM THE UNIT BEFORE CHANGING SPEED TAPS ON THE BLOWER MOTOR.
Refer to the wiring diagram in the appendix to verify speed tap settings.
For models equipped with PSC type motors, blower speeds are to be changed at the ignition control board. Both heat speed and cool speed terminals are supplied on the board along with two unused motor lead terminals.
Some models are equipped with X-13 motors. X-13 motors are constant torque motors with very low power consumption. This motor is energized by 24V. Adjust the CFM for the unit by changing the 24V low voltage leads to the speed terminal block on the motor.
Heating-White Lead | Cooling-Yellow Lead |
T1 - Low Speed | T4 - Low Speed |
T2 | - Medium Speed | T5 - High Speed |
T3 | - High Speed | |
NOTE: Heating airflow must be adjusted to provide the tempera- ture rise shown on rating plate.
Limit Check
Check limit control operation after 15 minutes of operation by blocking the return air grille(s).
1.After several minutes the main burners must go OFF. Blower will continue to run.
2.Remove air restrictions and main burners will relight after a cool down period of a few minutes.
