Operation, Chapter 5 operation, Temperature control humidity control – Grain Systems PNEG-236 User Manual
Page 11: Temperature control, Humidity control
PNEG-236 Humidistat-Thermostat
11
5. Operation
Temperature Control
1. Turn the fan unit ON and let it run 3 to 5 minutes to equalize temperature under the bin.
2. Set bypass switch to the “HUMIDISTAT OFF” position. This setting allows the unit to run based on
temperature only.
3. Rotate the thermostat knob clockwise to the warmest position.
4. Open the gas valves to the heater and turn the heater ON. Set heater gas pressure to a moderately
high setting (5 to 10 PSI).
5. Monitor the thermometer on the thermostat housing. When the thermometer comes up to the desired
temperature, slowly turn the thermostat knob counterclockwise until the heater cycles OFF.
6. If the unit does not reach the desired temperature, gradually increase the gas pressure until the
temperature rises to the desired level.
7. Watch the unit run through several cycles and make any final adjustments. (NOTE: The unit should
be on approximately 80% of the time. If not adjust gas pressure.)
8. Significant changes in outside air temperature may require readjustment of gas pressure.
Humidity Control
1. Set bypass switch to the “HUMIDISTAT ON” position. This setting allows the unit to run based on
temperature and humidity.
2. Set the thermostat (Humidistat-Thermostat units only) to the maximum temperature desired. This
allows the thermostat to function as a High-Limit control only. See the above
for setting the thermostat.
3. Set the humidistat to the desired relative humidity level you want to maintain under the drying floor.
The heater will cycle on above this relative humidity, and OFF when this level is reached.
4. Use the equilibrium moisture chart below as a guide for setting the humidistat.
Equilibrium Moisture Chart (Shelled Corn)
Boxed area indicates safe moisture for normal winter storage of shelled corn at 15%. Grain
to be stored through the summer or long term, needs to be 1 to 3 points dryer.
Air
Temperature
(F)
Relative Humidity - Percentage (%)
35
40
45
50
55
60
65
70
75
80
85
90
95
100
20°
11.2
11.7
12.7
13.7
14.5
15.1
16.2
17.1
18.0
19.6
21.2
23.5
25.8
29.1
30°
10.8
11.3
12.2
13.1
13.9
14.6
15.5
16.4
17.4
18.7
20.2
22.5
25.0
28.3
40°
10.5
11.0
11.7
12.5
13.3
14.0
14.8
15.5
16.6
17.8
19.4
21.5
24.2
27.5
50°
10.1
10.6
11.3
12.0
12.7
13.3
14.1
14.8
15.8
16.9
18.6
20.5
23.4
26.7
60°
9.7
10.2
10.9
11.6
12.1
12.7
13.4
14.2
15.0
16.0
17.8
19.5
22.6
25.9
70°
9.0
9.7
10.4
11.1
11.5
12.0
12.8
13.5
14.5
15.4
16.8
18.5
21.3
24.5
80°
8.3
9.1
9.8
10.5
10.8
11.2
12.1
13.0
13.9
14.8
15.8
17.4
20.0
22.8