This document contains supplemental guidelines for installing the Qt-series control and air distribution for the Dometic auxiliary air conditioning system on a Peterbilt 379 chassis with a 70" sleeper. It is intended to be used in conjunction with the standard installation manual, which covers all other aspects of installing, testing and operating this system.
These are suggestions based on previous installations. Please be creative in your installation, but keep functionality and safety in mind. Key issues are: evaporator discharge venting, evaporator return air and condenser air flow. Other issues include: controls accessibility, condensate removal and wire and hose chafe protection. Do not attempt to install any components until you read and understand the instructions in both manuals.
LOCATING THE COMPONENTS Peterbilt 379
The Dometic remote auxiliary air conditioning system consists of two basic components: an outside condensing unit, which contains the condenser and an exhaust fan, and an inside unit, which contains the compressor, heater, evaporator and blower (CHEB). The two units are connected by precharged refrigerant lines with quick-connect fittings.
Determine where best to install the CHEB (Fig. 1). Refer to the manual that came with the CHEB for more information. Keep in mind that the driver’s side luggage box is probably one of the most used storage areas, so for your ongoing storage convenience, consider the passenger's side luggage box, then the center storage area, and lastly the driver’s side box for CHEB installation. Use the CHEB template to determine the best place to mount the unit.
Installing the Control/Display Panel Peterbilt 379
Mount the control in such a location as to give the driver good access. The suggested location would be near the current HVAC controls, however, that may be very tough on some models (Figs. 3a-3b). Route the CXP cable through the wall or cabinet and into the luggage compartment, then to the rear of the bunk for later connection.
Installing the Power Logic Box Peterbilt 379
The Power Logic Box (PLB) is commonly mounted on the front wall of the driver’s side luggage box (Fig. 4). The PLB should be mounted in a relatively accessible location, within about 4 feet of the CHEB unit. The PLB comes with a mounting plate for mounting to a vertical surface. If you want to mount to a floor or other horizontal surface, remove the mounting plate (Fig. 5). The PLB must be mounted in a vertical position, see the label on the box for more information.
INSTALLING THE RETURN AIR VENT Peterbilt 379
The supplied return air vent(s) should be installed under the bunk, in the same area where the CHEB will be mounted. Your package may contain either one large grill with a mounting frame or two smaller 12.5" x 5.5" surface-mount grills. We suggest using a hole saw and reciprocating saw to cut out the hole for the large grill. If you received the two 12.5" x 5.5" grills instead of the one large grill, use a 4" hole saw to cut at least two holes behind each grill. Use of the recip-rocating saw is optional for those grills (Figs. 6-8).
Peterbilt 379 CHASSIS Service Repair manual For Free