Thermo Products MDA1-125N, MDA1-50N, MHA1-75N, MHA1-100N, MHA1-50N, MHA1-125N Room Thermostat

Models: MDA1-100N MDA1-125N MDA1-75N MHA1-125N MHA1-50N MHA1-100N MHA1-75N MDA1-50N

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All installations and services must be performed by qualified service personnel.

3.Electronic Air Cleaner and Humidifier Connections

The ignition module on this furnace has designated terminals to control the operation of an electronic air cleaner and/or humidifier. These terminals provide line voltage for the control of these accessories (See Figure 8).

NOTICE: It is important to confirm that the operating voltage of the humidifier or EAC being installed matches the output of this control. If not, a field supplied relay or transformer may be necessary to provide the proper control and supply voltage for the accessory being installed. See the manufacturers instructions for the humidifier or EAC for additional requirements.

4.Room Thermostat

A room thermostat is not furnished with this furnace. However, a thermostat is required to properly operate the furnace control system.

The room thermostat should be located in the natural circulating path of the room air. The thermostat should not be placed where exposed to cold air infiltration, i.e. drafts from outside openings such as windows and doors, or where exposed to air currents from supply or return air registers, or such that natural circulation of air is blocked, such as behind doors, in shelves, or in corners. It should always be located on an interior wall.

In addition, the room thermostat should not be exposed to heat from a nearby fireplace, electrical appliances, lamps, rays from the sun, or mounted directly on a wall containing warm air ducts, a chimney, or a gas vent. These sources of heat could adversely affect the operation of the thermostat, preventing it from properly controlling the room temperature.

Generally, a room thermostat should be set at the lowest temperature that is comfortable to the building occupants. This will result in the lowest cost to heat the building.

Proper control of the indoor temperature can only be achieved if the thermostat is calibrated to the heating and/or cooling cycle. A vital consideration of this calibration is related to the thermostat heat anticipator.

The proper thermostat heat anticipator setting is 0.8 AMPS for furnace operation only. To increase length of the heating cycles, increase setting of heat scale; to decrease length of cycle, decrease setting of heat scale.

Anticipators for the heating operation are of two types, pre-set and adjustable. Those that are pre-set will not have an adjustment scale and are generally marked accordingly.

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Thermo Products MDA1-125N, MDA1-50N, MHA1-75N, MHA1-100N, MHA1-50N, MHA1-125N, MDA1-75N, MDA1-100N service manual Room Thermostat