REGULATOR
COVER SCREW
PLASTIC
ADJUSTMENT
SCREW
ON/OFF SWITCH 
REGULATOR SPRING (PROPANE - WHITE) (NATURAL - SILVER)
| GAS PRESSURE |
| REGULATOR |
INLET | ADJUSTMENT |
PRESSURE TAP |
|
MANIFOLD
PRESSURE TAP
A07751
Fig. 13 - Single-Stage Gas Valve
If larger adjustments are required, change main burner orifices following the recommendations of national and local codes.
NOTE: All other appliances that use the same meter must be turned off when gas flow is measured at the meter.
Proceed as follows:
1.Turn off gas supply to unit.
2.Remove pipe plug on manifold (See Fig. 11) and connect manometer. Turn on gas supply to unit.
3.Record number of seconds for gas meter test dial to make one revolution.
4.Divide number of seconds in Step 3 into 3600 (number of seconds in one hr).
5.Multiply result of Step 4 by the number of cubic feet (cu ft) shown for one revolution of test dial to obtain cubic feet (cu ft) of gas flow per hour.
6.Multiply result of Step 5 by Btu heating value of gas to obtain total measured input in Btuh. Compare this value with heating input shown in Table 3 (Consult the local gas supplier if the heating value of gas is not known).
EXAMPLE: Assume that the size of test dial is 1 cu ft, one revolution takes 32 sec, and the heating value of the gas is 1050 Btu/ft3. Proceed as follows:
1.32 sec. to complete one revolution.
2.3600 ÷ 32 = 112.5.
3.112.5 x 1 =112.5 ft3 of gas flow/hr.
4.112.5 x 1050 = 118,125 Btuh input.
If the desired gas input is 115,000 Btuh, only a minor change in the manifold pressure is required.
Observe manifold pressure and proceed as follows to adjust gas input:
1.Remove regulator cover screw over plastic adjustment screw on gas valve (See Fig. 13).
2.Turn plastic adjustment screw clockwise to increase gas input, or turn plastic adjustment screw counterclockwise to decrease input (See Fig. 13). Manifold pressure must be between 3.2 and 3.8 IN. W.C.
!WARNING
FIRE AND UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal injury or death and/or property damage.
Unsafe operation of the unit may result if manifold pressure is outside this range.
3.Replace regulator cover screw on gas valve (See Fig. 13).
4.Turn off gas supply to unit. Remove manometer from pressure tap and replace pipe plug on gas valve. (See Fig. 11.) Turn on gas to unit and check for leaks.
Measure Manifold Pressure (Propane Units)
Refer to propane kit installation instructions for properly checking gas input.
NOTE: For installations below 2,000 ft (610 m), refer to the unit rating plate for proper propane conversion kit. For installations above 2,000 ft (610 m), contact your distributor for proper propane conversion kit.
Check Burner Flame
With control access panel (see Fig. 19) removed, observe the unit heating operation. Watch the burner flames to see if they are light blue and soft in appearance, and that the flames are approximately the same for each burner. Propane will have blue flame (See Fig. 12). Refer to the Maintenance section for information on burner removal.
Normal Operation
An LED
Airflow and Temperature Rise
The heating section for each size unit is designed and approved for heating operation within the
Table 10 shows the approved temperature rise range for each heating input, and the air delivery cfm at various temperature rises for a given external static pressure. The heating operation airflow must produce a temperature rise that falls within the approved range.
Refer to Indoor Airflow and Airflow Adjustments section to adjust heating airflow when required.
Limit Switches
Normally closed limit switch (LS) completes the control circuit. Should the
When the air temperature at the limit switch drops to the
15