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NORA Oilheat Technicians Manual

Location of the thermostat A thermostat should be installed about 5 feet from the floor on an inside living or dining room wall, or a wall where there is good natural air circulation. It may be wise to select several good locations, pointing them out to the homeowner, and then let them choose from the suggested locations. Some locations that will cause trouble are: 1. Above a TV, stereo, computer, or lamp 2. On or near an outside wall 3. Near a radiator or air register 4. In line with the air stream from a register 5. On a wall containing steam pipes, hot water pipes, warm air risers, or chimneys 6. On a wall with high internal air movement 7. Behind a door or other obstruction to free air circulation 8. In an over radiated or under radiated room 9. Near a window or door frequently opened to the outside 10. In a room with a heat source such as refrigerator, stove, or fireplace 11. On a wall or partition subject to excessive vibration Chapter 12—Limit Controls and Thermostats 12-7 to W circuit. This is because the anticipator is only used for heating and not in the circuit R and Y that would be used if this thermostat were used for air conditioning. Figure 12-6 shows the heater indicator and the scale in a thermostat. In some installations, longer operations may be needed to assure delivery of heat throughout the house. To lengthen operations, move the heater indicator preferably not more than half a division in the direction of the scale arrow. To shorten operations, move the indicator in the opposite direction. If the operating control supplies 0.4 amps to the thermostat circuit and the anticipating heater of the thermostat is set at 0.8 amps, the burning cycle will be long. However, if the heat anticipator of the thermostat is set at 0.2 amps while the control is supplying .4 amps, then the burner cycle will be short. In the latter case, the burner will operate on and off for short periods of time (short cycling). Electronic thermostats Figure 12-7 shows some examples of electronic thermostats. These thermostats rely on solid-state technology to not only operate the equipment, but to maintain and store temperature settings, day and date, and number of cycles. Unlike the earlier mechanical thermostats that had only one day per operation cycle, many of these thermostats can have four different settings for all seven days of the week. The difference in electronic thermostats over manual and mechanical clock types is the lack of an adjustable anticipator. Instead the electronic thermostat must be programmed according to ‘cycle rate adjustment’. Once these settings are made at the time of installation, the thermostat, and its circuitry accommodate for the correct number of cycles. Figure 12-6: T-87F heater adjustment Figure 12-7: Electronic thermostats Hole Suitable for Pencil Point to Move Indicator Heat Anticipator Indicator Scale Chapter 12 Limit Controls/Thermostats


NORA Oilheat Technicians Manual
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