LTD HEATER INSTALLATION
AIRSTREAM SURFACE MOUNT HUMIDISTAT (EDS SYSTEMS ONLY)
1.The humidistat can be used to directly control the operation of a heater for drying, or with addi- tional equipment, the operation of a fan for aeration.
2.The humidistat closes on a humidity rise. If the humidistat is set at 50% relative humidity and the humidity of the air sur- rounding the sensing unit on the humidistat is greater than 50% relative humidity, the micro- switch remains closed. When the humidity drops below 50% relative humidity the micro- switch opens. Power then ceases to travel through the hu- midistat, simultaneously shut- ting off the heater. If the humi- distat is used as an aeration control or fan control for natural air drying, additional equipment is required to control the fan power supply, so it runs when the humidistat is open.
3.The housing of the humidistat has a perforated bottom allow- ing air to surround the sens- ing element. The perforated bottom insures accurate sens- ing of the (outside) humidity. The housing also incorporates a vent hole at the top of one side. This guards against heat build up in the box, changing the relative humidity and de- stroying the heat sensing abil- ity of the unit. Also, air is drawn through the perforated bottom and across the sensing ele- ment of the humidistat. These design features insure accurate sensing of relative humidity.
4.The humidistat should be mounted with the back plate, corner holes on a corrugation hill. It should be positioned ap- proximately three feet from the ground or grade line as shown in the illustration.
5.The humidistat is used in con- junction with a temperature sensing control device (thermo- stat), which senses the drying air temperature. If the plenum air temperature exceeds the setting of the thermostat, the thermostat opens and the heater shuts off. When the plenum temperature drops below the setting of the thermostat, the thermostat closes and the heater turns on again. The thermostat is a safety device keeping the grain tem- perature equal to the thermostat setting. Some grains are more sensitive to temperature. Qual- ity, germination and value are lost due to high temperatures. Grains used for seed, rice and popcorn are adversely effected by high temperatures.
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