Suburban DynaPack S Series Architects And Engineers' Manual page 31

TO SHUT DOWN UNIT
To turn off the unit switch the room thermostat to OFF. Turn the electrical
power off and close the manual gas supply valve before performing any service
to the unit.
Heating Adjustments
1. Turn off the unit at the room thermostat and shut off the manual
gas valve.
See Figure 20
2. Connect a pressure gauge with suitable range (0 to 10" for natural and
0 to 15" for LP*) to the inlet pressure port on the gas valve.
3. Open the manual gas valve and turn the unit on.
4. Once the furnace is operating, check the inlet gas pressure. Adjust the
pressure regulator to obtain an inlet pressure of 5" to 7" water column
for natural gas and 11" to 13" for LP gas*.
5. Turn off the unit and shut off the manual gas valve.
6. Move the pressure gauge to the manifold pressure port on the gas valve.
.
See Figure 20
7. Once the furnace is operating, check the manifold pressure. Adjust the
gas valve pressure regulator to obtain a manifold pressure of 3.5" water
column for natural gas and 10.0" water column for LP gas*.
8. On natural gas installations the input to the furnace must be checked
to insure safe operation. Any other gas appliances that use the gas meter
must be turned off including the pilot lights.
9. With the DynaPack furnace running, count the time it takes for the gas
meter to make one revolution. Also record the gas meter rate of cubic
feet per revolution. You will also need the average heating value of the
natural gas for your location. Plug
these factors into this equation to
calculate the gas input rate to the
furnace in BTU per hour.
10. Your recorded value on input must be within + or - 2% of the rated input.
If it is not then adjust the manifold pressure lower to reduce the input or
higher to increase the input. Do not go outside of 3.2" to 3.8" water
column.
11. The only adjustment for LP gas* is to maintain the 10" water column
manifold pressure.
12. Turn off the unit, close the manual gas valve, and remove the pressure
gauge. Make sure the gas valve pressure port plug screws are tightened
along with the gas valve regulator cap. Replace the burner compartment
door.
13. Open the manual gas valve and turn on the furnace.
14. Place a thermometer in the return air along with one in the supply air
as close to the furnace as possible. Once the supply air temperature is
constant, record both temperatures. Subtract the return air temperature
from the supply air temperature. This difference is the temperature rise of
the furnace.
15. Compare the measured temperature rise to the nameplate range. If the
measured rise is lower than the nameplate minimum, then select the
next lower blower speed for the heating speed. If the measured
temperature rise is above the nameplate maximum, then select the next
higher blower speed for the heating speed.
16. If a new blower speed was selected then re-measure the temperature rise
and repeat the adjustment if needed.
.
BTU/HR Input =
.
See Figure 20
Cubic Feet Per Revolution
Number of Seconds Per Revolution
31
* LP gas available for
S Series only.
X 3600 X Heating Valve
(continued on next page)
Suburban DynaPack A&E Manual 07/2019 Rev.6