Setting Manifold Pressure for Two Stage Gas Control
1. Set the unit to high fire by setting the
discharge temperature control or
thermostat to its maximum setting. If the
ambient temperature is warm, the unit
may not stay at high fire.
2. Measure the burner manifold pressure at
the manifold pressure test port (see
Control Center Layout on page 3) using a
“U” tube manometer. The pressure on
high fire should be 3.5 in. wg for natural
gas and 10 in. wg for LP gas. To change
the pressure, adjust the regulator
adjustment screw on the combination gas
valve.
3. Set the unit to low fire by removing the
wire from the high fire terminal on the
combination gas valve.
4. The manifold pressure on low fire for natural gas
should be 0.88 in. wg and 2.5 in. wg for LP gas. To
change the pressure, use the low fire adjustment
screw on the combination gas valve.
Staged Burner Adjustments
Furnace Controls
For Energy Recovery Units without Temperature Control Package
The furnace stage controls are located in the furnace control center. One control is
provided for each stage of heating. The discharge temperature setting is located on
the control furthest to the left. The offset and differential settings for each stage are
preset at the factory; however, field-adjustments may be made to get the best control
for your application. See the literature provided with the controls for further
information.
For Energy Recovery Units with Temperature Control Package
If two-stage control is ordered with a Temperature Control Package, the controller in
the unit’s main control center will control the stages of heating. The temperature set
point may be adjusted on the controller (See Temperature Controller IOM).
Staged Temperature Controls
Performance Data
Ratings shown are for elevations up to 2000 ft. For higher elevations, the input should be reduced by 4% per 1000 ft. of
elevation above sea level. In Canada, from 2000 to 4500 ft in elevation, the unit must be derated to 90% of the input listed
above. The unit shall also be used in accordance with standard CGA 2.17.
High Fire Adjustment
Low Fire Adjustment
Solenoid
High Fire
Terminal
Air Temperature Rise Through Unit (°F)
Model Input Output 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Number (MBH) (MBH) CFM
PVF 100 100 80 3704 2963 2469 2116 1852 1646 1481 1347 1235 1140 1058 988 926 871 823 780 741
PVF 150 150 120 5556 4444 3704 3175 2778 2469 2222 2020 1852 1709 1587 1481 1389 1307 1235 1170 1111
PVF 200 200 160 7407 5926 4938 4233 3704 3292 2963 2694 2469 2279 2116 1975 1852 1743 1646 1559 1481
PVF 250 250 200 9259 7407 6173 5291 4630 4115 3704 3367 3086 2849 2646 2469 2315 2179 2058 1949 1852
PVF 300 300 240 11111 8889 7407 6349 5556 4938 4444 4040 3704 3419 3175 2963 2778 2614 2469 2339 2222
PVF 350 350 280 12963 10370 8642 7407 6481 5761 5185 4714 4321 3989 3704 3457 3241 3050 2881 2729 2593
PVF 400 400 320 14815 11852 9877 8466 7407 6584 5926 5387 4938 4558 4233 3951 3704 3486 3292 3119 2963
Figure 3: Staged Controls
Figure 4: Combination Gas Valve
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