03 Heating & Air Conditioning

Furnace

The MIDAS is equipped with a forced-air furnace fueled by LP gas. The furnace is controlled by the wallmounted Spyder Controls System (Figure 3-1), located inside the main hallway of the coach. Among other functions, this controls both the heating and air conditioning for the motorhome.

In the gas-heating mode, the furnace heats air, which, in turn, is circulated through ductwork in the floor of the motorhome. If any obstructions block the floor vents or air-return register, the furnace will not function properly. Any items stored under the cabinets must be carefully stowed to prevent damaging or crushing the furnace ducting or blocking the warm-air return.

NOTE: When a furnace is being used for the first time, there might be an initial “burn-off” of manufacturing compounds or residues left on the heat exchanger or in the ductwork, which could produce odors, fumes, and possibly some smoke. This is normal and should not cause concern, unless it persists for an excessive amount of time.

To minimize the after-effects of this “burn-off” process, the initial use of the furnace must be done with all the doors and windows open to permit normal air circulation to dissipate these odors and fumes.

For routine operation of the furnace, set the thermostat to the desired temperature setting and then turn the thermostat to gas heat. In about a minute, the furnace will begin to operate and warm or hot air will come through the ductwork.

To shut down the furnace, turn the thermostat to the OFF position. Even though the thermostat might be turned OFF, the furnace system will continue to run for about a minute or so to permit a gradual cooldown of the heating system, which is normal.

On a regular basis, thoroughly clean the complete furnace and air-tube passageways to remove dust, lint, and any other possible obstructions. Leak-test the entire LP gas system at least annually. Also, check and clean the air-blower system annually.

Any access hatches to the furnace are for authorized service personnel only, as there are no userserviceable parts on the furnace. Accordingly, do not attempt to tamper with the interior of the furnace.

Before the beginning of each travel season, the furnace must be thoroughly cleaned and inspected. Any obstructions, debris, or lint, which might obstruct free airflow or impede the operation of the air circulation system, must be removed. For example, accumulated dust or lint could possibly obstruct the orifices for the pilot light or might accumulate on the blower blades and unbalance the operation of the blower. Additionally, any debris in the ductwork, when heated by the furnace, could emit unpleasant odors or possibly become a fire hazard.

The furnace system must be periodically cleaned. Annual cleaning is recommended unless the motorhome is subjected to dust levels significantly greater than average, in which case more frequent cleaning is recommended. The Owner’s Information Package provides recommended cleaning tips and procedures. When needed, a more thorough cleaning must be performed by a qualified service technician.

Air Conditioning System

The factory-installed air-conditioning system is designed for 120 VAC power supplied either from the external power cord or from the generator. For the best cooling scenarios, park the motorhome in a shaded location whenever possible and close drapes on the windows exposed to direct sunlight.

The air-conditioned, cooled air is emitted through the vents (Figure 3-2), which are located in the roof throughout the entire coach along the passenger side. The return air vents run parallel, front to back, on the ceiling along the driver’s side of the coach. The return vents are similar to the air conditioning vents, but they contain foam filters that keep dust from flowing back through the air conditioning system. The return filters can be easily removed and cleaned with warm water and a mild cleaning solution. To remove the filter, pull the vent down and lift the filter from inside the opening.

Thermostat on Spyder Controls System

The following is an overview of how best to use the thermostat on the Spyder Controls System (Figure 3-3). For detailed instructions, refer to the thermostat literature in the Owner’s Information Package.

1. Push the THERMOMETER icon on the Spyder Controls System. This will bring up a touch screen to select the desired function (e.g., A/C, HEAT PUMP, FURN, or OFF).

NOTE: In the A/C mode, there will be a delay of several minutes before the refrigerant in the air-conditioning system begins to cool the motorhome, as the compressor is on a time delay circuit and it must also cool the ductwork to the vents first.

2. Select the Fan Mode operation (AUTO) or set the Fan Speed operation (LOW or HIGH) to select the fan speed desired.

3. Press the Up or Down buttons to set the desired temperature for the motorhome.

• NOTE: When the fan is on AUTO mode, the fan will turn on and off when the temperature reaches the desired setting.
• When the fan is on LOW or HIGH mode, it will continue to run even though the compressor cycles on and off when it reaches the desired temperature.
• If the motorhome temporarily loses its 110V power, the air conditioning system will resume operation at its last programmed setting once power is restored.
• If 12V power is lost to the thermostat, it will automatically reset to 72 degrees once power is restored.

NOTE: There is a thermostat control for each air conditioning unit.

Heap Pump Controls

To activate the optional heat pump, set the thermostat to the ELEC HEAT mode and select the desired temperature.

NOTE: If the setting on the thermostat and the room temperature are more than five degrees apart, the gas furnace will automatically turn ON with the heat pump. Once the room temperature reaches the desired level specified on the thermostat setting, the furnace will cut off and the heat pump will maintain the heating of the coach.