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COMBINATION THERMOSTAT/HUMIDISTAT (HT-3000)
The HT-3000 contains a thermostat and humidistat. The controls are wired in series and will over-ride
each other when they are “satisfied”.
The HT-3000 is designed to activate the heater only when additional heat is needed to provide adequate
drying. Quite often during the drying season, the ambient conditions are such that adding heat to the
drying air is not necessary. The HT-3000 senses the relative humidity of the air supplied to the grain, and
calls for heat only if the relative humidity is above the set point. At the same time, the temperature
portions of the HT-3000 will sense the temperature of the air supplied and, if the humidity is above the set
point, will activate the heater so the temperature does not exceed the set point.
The HT-3000 works best in one of the following configurations.
1.
Drying for a reduction with humidistat only; set the thermostat high enough to activate the
humidistat, but lower than a temperature that could damage the grain. Adjust the humidistat to
desired reduction of humidity. In this setting, the thermostat acts as a high limit. This is best
achieved with a super-low heater. If high temp heater is used in this configuration be sure to set
gas pressure low. (See Operating Instructions below)
Example: If the humidistat setting was 70% and the thermostat setting was 120 degrees (F), a relative
humidity inside the plenum of above 70% would cause the control to turn the heater on. The heater
would continue to operate until the temperature exceeds the 120 degrees thermostat setting or the
relative humidity dropped below 70%. As long as the relative humidity remains about 70%, the heater
will cycle in response to the thermostat setting; when the relative humidity drops and no supplemental
heat is required, the humidistat setting will dictate and the heater will not operate.
3.
Drying for reduction with air and supplemental heat only; simply set the humidistat on its lowest
level, calling for heat. Set thermostat to desired temperature.
OPERATING INSTRUCTION
1.
Follow installation instruction on page 22; be sure bottom of enclosure is not sealed. Air
circulates threw enclosure.
2.
Start fan and heater according to separate instruction found on page 16 and 17.
3.
Set humidistat dial at 5% or lowest possible setting. Set thermostat on its highest value.
4.
Adjust the heater gas pressure so that the thermometer in the HT-3000 stabilizes at a temperature
10 to 20 degrees above desired temperature.
Note: It should not take longer than a few minutes for the temperature to stabilize.
5.
Change thermostat to desired temperature. This should be 10 to 20 degrees less than where you
have stabilized the gas pressure. Watch several cycles to insure heater is operating within the
setting you have selected. The heater should cycle to maintain your setting. If you feel that heater
is cycling too often, check to be certain air is moving through the control and out the bottom.
Without airflow through the control, reaction time and temperature range will be excessive.
