Dometic Peterbilt 379 CHASSIS Instruction sheet

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Dometic Environmental Corporation
Rev. 20080221
ID: 2520
REMOTE AUXILIARY AIR CONDITIONING
AND AIR DISTRIBUTION FOR
PETERBILT 379 CHASSIS
INSTALLATION GUIDELINES
for Peterbilt Truck Model 379 with a 70" Sleeper

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COPYRIGHT © 2008 Dometic Environmental Corporation, All Rights Reserved.
No part of this publication may be reproduced, translated, stored in a retrieval system, or transmitted in any form or by any means electronic, mechanical, photo-
copying, recording or otherwise without prior written consent by Dometic Environmental Corporation. Every precaution has been taken in the preparation of this
manual to insure its accuracy. However, Dometic Environmental Corporation assumes no responsibility for errors and omission. Neither is any liability assumed for
damages resulting from the use of this product and information contained herein.

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Peterbilt 379 Installation Guidelines
CONTENTS
INTRODUCTION 4
LOCATING THE COMPONENTS 5
INSTALLING THE CONTROL 6 – 8
INSTALLING THE RETURN AIR VENT 9
INSTALLING THE SUPPLY AIR DISTRIBUTION 10 – 11

INTRODUCTION
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.
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Peterbilt 379 Installation Guidelines
4

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Peterbilt 379 Installation Guidelines
LOCATING THE COMPONENTS
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.
The Dometic condenser may be installed either under
or behind the sleeper (Figs. 2a-2b).
IMPORTANT!
Refer to the Dometic installation manual
for details on installing and connecting the
CHEB and condensing unit.
Figure 1 - CHEB installed in luggage compartment
Figure 2a - Condensing unit mounted under truck
Figure 2b - Condensing unit mounted on back of sleeper

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Peterbilt 379 Installation Guidelines
6
Figure 3a - Control/Display panel mounted
Figure 3b -Alternative Control/Display panel mounting location
Control mounted
Control mounted
INSTALLING THE CONTROL
Installing the Control/Display Panel
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.

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Peterbilt 379 Installation Guidelines
Installing the Power Logic Box
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.
Figure 4 - Possible PLB mounting location
Figure 5 - Fastener location on PLB

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Peterbilt 379 Installation Guidelines
ROUTING CABLES
The box contains several types of cables:
• Wires enclosed in split loom
• Flexible power cables
• Phone-type cables
The wires in split loom go to the CHEB unit. The
flexible power cables go to the power distribution
panel. The phone cable mounted on the CHEB unit
plugs into the hole marked TSEP. The phone cable
from the Control/Display plugs into the hole marked
Display.
All cables should be neatly routed and clipped to
prevent chafing.
IMPORTANT!
Refer to the Dometic installation manual for
details on routing and connecting cables
from the Control/Display panel to the PLB
and CHEB.

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Peterbilt 379 Installation Guidelines
Figure 6 - Location for cutting return air vent
Figure 7 - Return air vent hole cut
INSTALLING THE RETURN AIR VENT
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).
Remember, good air flow from the return air grill
to the CHEB evaporator coil is critical for your
air conditioning system to perform correctly. Do
not allow anything to block this air flow.
Figure 8 - Return air grill ange installed

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Peterbilt 379 Installation Guidelines
INSTALLING THE SUPPLY AIR DISTRIBUTION
For this installation, we will install 4" ducts. Depend-
ing on the capacity of the system, you may have
two or three vents supplied. You must use all vents
supplied with the kit to get the rated air flow out of
the system.
This kit comes with a duct combiner that allows one
4" duct to be vented into the truck’s pre-existing air
distribution system. Find the combiner (Fig. 9), and
mount to the bottom of the plastic duct that runs from
the truck’s HVAC unit to the rear wall of the sleeper.
You will have to cut out the duct so that the flapper
damper can operate. Secure with screws.
The remaining 4" grill(s) can be located wherever you
choose, however, be aware that cold air falls and hot
air rises. It is best to install at least one vent high in
the cab. Be creative. Use existing features to mount
grills or hide ductwork, such as: cabinets, closets,
bunk tray at the foot of the bed, wire chases, etc. The
bunk tray is a good way to use what is existing:
• On the 379, 70" sleeper, remove the bunk tray
at the foot of the bed. Cut a 5" hole in the metal
below, and a 4" hole in the bunk tray in the same
area. Mount one 4" vent into the bunk tray. Run
the 4" duct up through the hole in the metal, and
connect to the grill with a hose clamp. Replace
the bunk tray.
Figure 9 – Duct combiner