Dometic 39626.506, 39626.501, 39726.506, 39726.501 User Manual

INSTALLATION INSTRUCTIONS

RECORD THIS INFORMATION FOR FUTURE REFERENCE BEFORE INSTALLING THE UNIT:

Model Number Serial Number Date Purchased Place of Purchase

SELF-CONTAINED

AIR CONDITIONER & HEA T PUMP

FOR

USA

SERVICE OFFICE Dometic Corporation 2320 Industrial Parkway Elkhart, IN 46516 574-294-2511

CANADA

Dometic Corporation 46 Zatonski, Unit 3 Brantford, ON N3T 5L8 CANADA 519-720-9578

For Service Center Assistance Call:

800-544-4881

RECREATIONAL VEHICLES

ROT ARY COMPRESSOR

SYSTEM MODELS

Air Conditioners

39626.501 & 39626.506 Heat Pumps

39726.501 & 39726.506

THIS UNIT IS DESIGNED FOR OEM INSTALLATION

ALL INITIAL INSTALLATIONS MUST BE APPROVED BY THE SALES DEPT.

AVERTISSEMENT

WARNING

This manual must be read and understood before installation, adjustment, service, or maintenance is performed. This unit must be installed by a qualified service technician. Modification of this product can be extremely hazardous and could result in personal injury or property damage

Lire et comprendre ce manuel avant de procéder à l'installation, à des réglages, de l'entretien ou des réparations. L'installation de cet appareil doit être effectuée par un réparateur qualifié. T oute modification de cet appareil peut être extrêmement dangereuse et entraîner des blessures ou dommages matériels.

APPLICATION MANUAL

INSTALLATION INSTRUCTIONS

REVISION:

AND

SYSTEM

MODELS

39626.501

39626.506

Important: Instructions must stay with unit.

Owner read carefully

39726.501

39726.506

INSTALLATION INSTRUCTIONS

TABLE OF CONTENTS:

1.0 SAFETY INSTRUCTIONS ...........................................................................PAGE 3

2.0 APPLICATION MANUAL ............................................................................. PAGE 4

2.1 AIR DISTRIBUTION...........................................................................PAGE 4

2.2 HOW ROOM AIR IS RELATED TO OUTLET PERFORMANCE .....PAGE 7

2.3 SPECIFICATION AND REQUIREMENTS.........................................PAGE 7

2.4 HIGH-POT REQUIREMENTS............................................................PAGE 8

2.5 MOUNTING IN COACH......................................................................PAGE 9

2.6 WIRING DIAGRAM 39726.501 & 39726.506 ..................................... PAGE 10

2.7 SPECIFICATIONS-HEAT PUMP ....................................................... PAGE 10

2.8 WIRING DIAGRAM 39626.501 & 39626.506 ..................................... PAGE 11

2.9 SPECIFICATIONS - AIR CONDITIONER ......................................... PAGE 11

3.0 INSTALLATION MANUAL ........................................................................... PAGE 12

3.1 GENERAL INSTRUCTIONS.............................................................. PAGE 12

3.2 PROCEDURE ....................................................................................PAGE 12

3.3 ELECTRICAL WIRING ......................................................................PAGE 14

3.4 CONTROL SYSTEM WIRING............................................................PAGE 14

3.5 SYSTEM CONFIGURATION AND CHECK OUT ..............................PAGE 16

INSTALLATION INSTRUCTIONS

1.0 SAFETY INSTRUCTIONS

This manual has safety information and instructions to help users eliminate or reduce the risk of accidents and injuries.

RECOGNIZE SAFETY INFORMATION

This is the safety-alert symbol. When you see this symbol in this manual, be alert to the potential for personal injury .

Follow recommended precautions and safe operating instructions.

UNDERSTAND, SIGNAL WORDS

A signal word , WARNING OR CAUTION is used with the safety-alert symbol. They give the level of risk for potential injury .

WARNING

ous situation which, if not avoided, could result in death or serious injury .

CAUTION

ous situation which, if not avoided may result in minor or moderate injury .

CAUTION

symbol indicates, a potentially hazardous situation which, if not avoided may result in property damage.

indicates a potentially hazard-

used without the safety alert

Read and follow all safety information and instructions.

INSTALLATION INSTRUCTIONS

2.0.0 APPLICATION MANUAL

2.1 AIR DISTRIBUTION

2.1.1 GENERAL INFORMATION

The purpose of an air conditioning system is to provide environmental conditions in a space to keep its occupants comfortable.

The basic elements of a simple forced circulation air system consists of a cooling unit, a centrifugal blower, a temperature sensing device controlling operation of the compressor and blower, suitable air filters, and a duct system.

Air is filtered, cooled, and distributed to various areas of the vehicle. Duct work should deliver this conditioned air as directly, quietly, and economically as possible. If the distribution is not properly sized and balanced, flow of air will not be as calculated and the system will not function properly or efficiently.

2.1.2 THE BASIC AIR CONDITIONING CYCLE

The components which are basic to air conditioning systems are illustrated by Figure 2.1. Air is treated at the conditioning unit, transferred to the conditioned space through the supply duct system and returned to the conditioning unit through the return system. The duct systems are also referred to as the distribution system.

2.1.3 FUNCTION OF A DUCT SYSTEM

A duct is a tube, or pipe, that carries air between two points. Strictly speaking, in air conditioning terms, a duct system is the arrangement of ducts between air conditioning equipment and rooms to be cooled, not including such items as filters, cooling coils, etc. However, we shall include in our use of the term “duct system”, every item in the air-passage network that offers resistance to air flow. From the standpoint of the blower it makes no difference whether a resistance is caused by filters or by the use of a small duct; effect will be the same. Resistance tends to restrict flow of air through the entire system.

of the greatest heat loss and/or heat gain. The effects of the gain or loss can then be offset by the supply air. It is important that the selection of the diffusers and grills for the supply and return systems receive careful attention to enable them to accomplish their purpose.

Consideration must be given to all aspects of the supply air distribution patterns: throw, spread, drop, etc. Also, the outlet and return grille velocities must be held within reasonable limits. Any noise generated at the grille is equal to or greater in importance than duct noise.

A window air conditioner (Figure 2.2) is essentially a device with a minimum duct system, since the only items that offer resistance to air flow are built into the cabinet.

2.1.4 FACTORS AFFECTING RESISTANCE TO AIR FLOW

Common observations of daily events tell us something about factors affecting resistance to air flow. We know, for example, that more pressure is required to force a given rate of air flow through a small duct than through a large duct. We also know that streamlining of ducts means less resistance to air flow, and that sharp angled turns must be avoided.

As air passes through ducts, cooling coils, grilles, diffusers, and dampers, the static pressure is reduced by friction and turbulence losses. Good duct design minimizes the need to balance the duct system by sizing the ducts such that the designed pressure drop allows the desired airflow rate to be delivered to each room. An improperly sized duct system will require extensive balancing. Balancing is a procedure by which the air flow allotment is adjusted to supply the correct quantity of conditioned air to each room.

COOL AIR DISCHARGE

INTO ROOM

HEATED AIR FROM

CONDENSER DISCHARGED

OUTDOORS

A forced air system is only as good as its air delivery system. Comfort levels are affected by the quantity and velocity of air movement within the space and the proper mixing of the supply air with the room air. Supply air should be furnished in a manner that will direct the air to the sources

CONDITIONED

SPACE

SUPPLY DUCT

SYSTEM

Block diagram of comfort air conditioning cycle.

Arrows indicate direction of air flow.

FIG. 2.1

RETURN DUCT

SYSTEM

CONDITIONING

UNIT

ROOM

WARM ROOM AIR TO BE COOLED

The Window Air Conditioner represents a minimum duct system, since air to and from the cooler is handled without external ducts.

EVAP

AND FAN

COMPRESSOR,

CONDENSER

AND FAN

FIG. 2.2

OUTDOORS

OUTDOOR AIR TO CONDENSER

INSTALLATION INSTRUCTIONS

2.1.5 AIR FLOW AND FRICTION

Air flows in a duct system from a region of high pressure to a region of lower pressure. The blower creates the pressure differential which causes the air flow through the duct system. The point of highest pressure in the system is at the outlet of the blower. The point of lowest pressure in the system is at the return opening of the blower. The air pressure constantly decreases as the air flows through the system. The pressure ultimately diminishes to zero as it passes through the register and is diffused into the conditioned space. As air moves through a duct, a pressure drop occurs due to the friction between the air and the walls of the duct. Another factor in pressure drop is the turbulence within the air stream itself. Air moving within a duct does not flow in a placid stream. Rather it moves in a churning and mixing path, or “turbulent flow.” The cumulative effect of rubbing friction and turbulence friction is friction loss. Air turbulence in a duct system becomes substantial whenever there is a change in the direction of air flow.

2.1.6 ECONOMICS OF DUCT DESIGN

In order to match to the system air delivery capacity, elbows for turning the air must be kept as large as allowed by the unit construction. Duct depth for Dometic air conditioners

may vary with each model series. Confirm the system to be installed and refer to Figure 3.4, for specific duct configurations required. High loss elbows must have their

resistance lowered by the use of splitters or turning vanes. Refer to Figure 2.3 through 2.7.

Another factor in duct losses is air leakage. Although leakage is not considered in duct design it should be an installation consideration. Cold air leaking into the surrounding cavity will cause condensation to form under high humidity conditions. Sealing all joints will assure moisture free cavities and maximum distribution of air to the outlets.

In most cases of high resistance encountered in duct systems, one or more of the following points have been overlooked by the installer:

A. Small Diameter

Pressure losses increase as diameter of a duct is reduced. Good design practice is that which enables the installer to put in the smallest size duct that will do the job of delivering required airflow rate with pressure available. No single size of duct will prove to be ideal for all jobs.

B. Length of Duct

Pressure loss increases as duct length is increased. This is almost obvious; a duct which is 6 ft. long has twice the pressure loss of one that is 3 ft. long, provided that both ducts are the same size and both are carrying the same airflow rate.

C. Changes in Direction (Figure 2.7)

Pressure losses increase when direction of air flow is changed. When air is forced to make a 90° turn in a duct system, pressure loss is much greater than for a straight run of the same length. (Refer to FIG. 2.7)

Item 1. This sharp-angled bend causes a large pressure loss. A simple way of visualizing such pressure loss is to imagine that these diagrams represent highways on which you are driving a car. As you approach a bend you are forced to slow the car speed to 15 mph. In so doing, a considerable part of energy of the fast-moving car has had to be absorbed by the brakes. The analogy holds for air particles flowing around a sharp bend. Item 2. This sharp-angled bend on the inside corner causes great pressure loss. The rounded corner on the outside does not help as much as might be anticipated. Item 3. This is a common form of 90° bend that has relatively low resistance. Item 4. If minimum resistance is desired, this extreme example of a smooth, streamlined fitting can be used, although space requirements will be prohibitive in many installations. Item 5. Occasionally, a beam or rafter prevents the use of a smooth bend and a right angle bend is necessary. In such cases the use of turning vanes (splitters) will be effective in reducing resistance. Item 6. Another way to reduce resistance is to change item (3) to a modified version of item (4) by inserting splitters in the sharper bend.

D. Sudden Contraction

When air is suddenly contracted from a large duct to a small duct, a pressure loss occurs See Figure 2.8.

E. Sudden Expansions

The pressure loss resulting from the sudden expansion of air from a small duct to a large duct, are much larger than losses due to sudden contraction. As with sudden contraction, much can be done by making air expansion gradual, rather than abrupt. See Figure 2.9.

To summarize Section 2.1.6, the following items contribute to higher pressure losses in a duct system:

1. Smaller diameter ducts

2. Longer duct lengths

3. Changes in direction of air flow

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