Little or No Heat is Produced by the Heating Unit

Usage:

Little or No Heat is Produced by the Heating Unit

CONFIDENTIAL TIBU3792-00

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TECHNICAL INFORMATION BULLETIN	February 12, 2003
MINI HYDRAULIC EXCAVATORS	304CR (NAD); 305CR (DSA)
	Component Code(s) 1812

SUBJECT: LITTLE OR NO HEAT IS PRODUCED BY THE HEATING UNIT

PROBLEM:

Poor cab heater performance may be caused by a kink in the heater hose. This kink is due to a tight radius in the routing of the water hose.

SOLUTION:

If your machine is experiencing this type of problem with the heater, check for a kinked heater hose.

Use the following procedure to determine if your machines heater hose is kinked. The procedure to fix the kinked heater hose is also outlined.

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Required Parts
Qty	Part Number	Description
1	4P-7581	Clip
1	096-0061	Strap
1	7X-2536	M8 Bolt
1	8T-4224	Washer

Illustration 1. Front of the seat.
(1) Screws
(2) Front Cover

Remove front cover (2) from the seat support by removing the 6 screws (1). This will expose the heating unit.

Illustration 2. Seat support with front cover removed.
(3) Bolts
(4) Case Cover

Remove case cover (4) of the heating unit by removing the 6 bolts (3). This will expose the heater hose that is possibly kinked.

Illustration 3. Photograph of a kinked heater hose.
(5) Kinked heater hose
(6) Weld Boss (Not visible)
(7) Heater Case

Attach the 4P-7581 Clip to weld boss (6) on heater case (7) by using the 7X-2536 Bolt and the 8T-4224 Washer.

Illustration 4. This side view is showing the heater hoses under the seat.
(5) Heater hose
(8) 096-0061 Strap
(9) 4P-7581 Clip

Attach heater hose (5) to the 096-0061 Strap with the 4P-7581 Clip.

Note: It is not necessary for you to change the hose while the machine is in the field.

Note: The standard heating hose has enough length to allow for the alternative routing that is outlined in this publication.

Reassemble case cover (4) that was removed in step 2.
Reassemble front cover (2) that was removed in step 1.

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Little or No Heat is Produced by the Heating Unit Caterpillar