Continuation of Heating System

Now that we have discussed the components of the heating system and their general operation, we will pull it all together into what the entire system does and it optimal operation.

It is important to periodically check your system, not just for defects, but for regular maintenance items.  Some examples of maintenance items would be things like filters that you might have in the floor vents, dirt that may have accumulated in and around your heater core area, both intake and return water lines, and, of course, any electrical connections.  Each specific coach should have a schematic indicating the flow of water through the heating system.  

For most coaches, the interior of the coach is heated by an underfloor, forced air system using hot water.  Controls for the temperature may differ from one coach to the next.  They can be either air or electrically operated, depending on the manufacturer preference.  In both cases, these control function to control the primary flow of water through the system.

The grad-u-stat which is used for controlling the coach temperature is located in the right recirculating air duct, which is located under the passenger seat.  Some coaches are equipped with a special temperature control rheostat.  This rheostat is usually mounted on the driver control panel.

The hot water used in this system is supplied by the engine cooling system.  It is then moved to the heater core compartment by way of the supply line using both the engine water pump and the water booster pump.  From there it warms the air moving across the core by way of the circulating fan and blower motor.  Outside air for ventilation or defrost is admitted to the heater or is drawn in by the blower motor.  The water modulator valve and the water circulation pump are may be located with this same compartment. 

After circulating through the heater core, the water returns to the engine by way of the return water line.  Warm water from the booster pump is routed to the defroster heater core which is located at the front of the coach in the driver's compartment.  Warm air from the heater compartment is directed by way of a damper/vent to defrost the windshield and warm the driver's area. Once it goes through this heater core, it also returns to the engine. That completes the cycle of the heating system.

Naturally, when you have mechanical items that must work in unison for things to operate properly, there is always room for failure.  These failures/errors can cause under-heating problems, over-heating problems or a combination of both.  For example, the grad-u-stat setting can cause either situation. If the setting is too low, if it is out of calibration or if the unit is sticking, it will cause under-heating.  If the setting is too high, it can cause over-heating.  With using just that one part as an example, you can surely see how critical proper operation and function of each part can change the functioning of the entire system.

There is a basic trouble-shooting guide that can be made available upon request.  Just send us an e-mail to busfixx@gmail.com.  We will be happy to send it to you for reference.

Remember that this blog is for informational purposes only and is not intended to take the place of a qualified mechanic when one is deemed necessary.

Sources: RTS maintenance manual, Eagle manual, GMC manual