HEATER INSTALLATION INSTRUCTIONS FOR MODEL CD25K KIT, P/N CD940-25K12 AND CD940-25K24, MODEL CD35K KIT, P/N CD940-35K12 AND CD940-35K24, MODEL CD45K KIT, P/N CD940-45K12 AND CD940-45K24
Piper PA-23 Aztec · Wiring Diagram
Overview
This document provides detailed installation instructions for combustion heater kits designed for Piper PA-23 Apache and Aztec aircraft. It outlines the necessary steps for removing existing heaters and installing new C&D Associates combustion heaters, including wiring connections and safety precautions. The instructions are intended for aircraft maintenance personnel and ensure compliance with FAA regulations. Key information includes wiring diagrams, installation procedures, and notes on airworthiness limitations and operational checks.
- The document is for Piper PA-23 Apache and Aztec models.
- Installation of the new heater requires specific wiring connections to terminal strips.
- Weight change: Old heater (18 lbs) replaced by new heater (25 lbs).
- Compliance with FAA-approved Airworthiness Limitations is required.
- Electrical connections must be verified with volt and ohm meters.
Document
Source
Originally published by janitrol.aero. Sprinkle hosts a reference copy with an added summary, specifications and searchable full text.
Document details
- Type
- Wiring Diagram
- Year
- 2001
- Pages
- 16
- File size
- 384 KB
- Publisher
- janitrol.aero
Common. Rarer than 17% of the aircraft models we track.
Most owners only have the POH. Here's the essential set for the Piper PA-23 Aztec.
- Pilot's Operating Handbook / AFM
- Checklist
- Maintenance Manual
- Parts Catalog (IPC)
- Systems & Wiring
- Service Bulletins
- Type Certificate (TCDS)
Free — save the PA-23 Aztec 250 to your watchlist and track it in one place.
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In this document
Installation Instructions
The installation process begins with the removal of the existing heater as per the Aircraft Service Manual. The new heater must be connected using specific airframe wires identified in the instructions. The document details the connections for various wires to the new heater terminal strip, including grounding and connections for the combustion air blower.
Safety and Compliance Notes
The document emphasizes the importance of following the Combustion Heater PREFLIGHT/OPERATIONAL CHECK AND SHUTDOWN PROCEDURE. It also mentions that compliance with the enclosed Airworthiness Limitations is mandatory and that the current Airworthiness Directive Piper AD 96-13-03 does not apply to the new heater.
Weight and Balance Considerations
The installation of the new heater will result in a weight change, as the new C&D heater weighs 25 pounds compared to the 18 pounds of the old South Wind heater. This change must be accounted for in the aircraft's weight and balance calculations.
Electrical Connection Hints
The document provides hints for electrical connections, including how to identify hot wires and ground connections using a voltmeter and ohmmeter. It also advises on the removal of old thermostats if applicable.
Safety notes
- Full compliance with the enclosed ‘Combustion Heater Airworthiness Limitations’ is required.
- Current combustion heater Airworthiness Directive Piper AD 96-13-03 does not apply to the new heater.
Full document text
302 POST ROAD, BUCHANAN, MI, USA PHONE: 616-695-7469 FAX: 616-695-6004 C&D ASSOCIATES, INC. IN 940 MOD I Rev. D dated 1/15/01 Page 1 of 2 HEATER INSTALLATION INSTRUCTIONS FOR MODEL CD25K KIT, P/N CD940-25K12 AND CD940-25K24, MODEL CD35K KIT, P/N CD940-35K12 AND CD940-35K24, MODEL CD45K KIT, P/N CD940-45K12 AND CD940-45K24 For Piper Aircraft PA-23 Apache 12 and 24-volt models, Aztec S/N 27-1 thru 27-3049, 27-3051 thru 27-3053. 1. Follow the Aircraft Service Manual or other FAA approved source for removal of the existing comb. heater. 2. Install the C&D Associates, Inc., TSO-C20 Approved combustion heater utilizing the existing Aircraft Service Manual or other FAA approved source where applicable. A. When removing electrical connections from the old heater, identify airframe wires H2B, H4A, H5A, H9A and H10A. These wires will be used in the new installation. Tape off H2A and H3B wires. On the new heater terminal strip, connect H5A wire to terminal 1. Connect H8A wire to terminal #5 (ground). Connect H4A and H10A wires to terminal #6. Connect H2B wire to terminal #2. Connect H9A wire to vent blower red wire with knife splice. Refer to typical wiring schematic figure 7 page 24 of Maintenance Manual for Aircraft Combustion Heaters Model CD25K, CD35K, CD45K. B. Remove the old safety valve and fuel filter assembly from the firewall mounting bracket. Fuel injected aircraft: Install the new shut-off solenoid valve in its place and secure with clamp. Carborated aircraft: Install the new fuel pump with the removable end cap down, using the legs of the pump as a template for the new bolt pattern. Connect the fuel lines to the remote shut-off (fuel pump) and to the heater. C. Install exhaust pipe and shroud included with the heater kit. Secure with two stainless steel 10/32 bolts supplied with exhaust pipe. D. Install the combustion air blower above the heater on the existing shelf and connect to the combustion air inlet. Connect the short black wire to airframe ground and positive red wire to heater terminal strip at terminal #1. E. The adjustable duct switch P/N RA-21253 is to be installed aft of the heater in the plenum. Make two 1/16" holes 2-5/8" apart in a convenient location. Half way between the 1/16" holes, drill a 1/2" hole for the thermister and mount the switch using two sheet metal screws. Red wire to terminal #2, blue wire to terminal #3 and yellow wires to thermostat. 3. Follow the ‘Combustion Heater PREFLIGHT/OPERATIONAL CHECK AND SHUTDOWN PROCEDURE’ outlined within the Combustion Heater “Air-worthiness Limitations”, First Edition, Revision none, dated 07-01- 95, included with these instructions. This FAA-approved Airworthiness Limitations must become a permanent part of the Aircraft Operations and Procedures manual. 4. NOTE: Full compliance with the enclosed ‘Combustion Heater Airworthiness Limitations’ is required. 5. NOTE: Current combustion heater Airworthiness Directive Piper AD 96-13-03 does not apply to the new C&D Associates, Inc. combustion heater. 6. NOTE: Utilizing existing aircraft combustion heater operating instructions or other FAA approved combustion heater operating instructions where applicable. 7. NOTE: Removal of the combustion heater and the installation of the C&D Assoc. Products TSO-C20 approved heater will have no affect on electrical load. Optional hour meter is connected to terminal #2. Optional overheat light may be connected to terminal #4 on the heater strip. 302 POST ROAD, BUCHANAN, MI, USA PHONE: 616-695-7469 FAX: 616-695-6004 C&D ASSOCIATES, INC. IN 940 MOD I Page 1 of 2 8. NOTE: For extreme conditions, fuel consumption may be as much as two gallons per hour. See operation hand-book instruction. (Insert into current operating hand-book.) 9. NOTE: Weight and balance change: Remove South Wind heater weighing 18 pounds and install C&D heater weighing 25 pounds. Due to aircraft variables, the following additional instructions may be helpful: 940 KIT - ELECTRICAL CONNECTION HINTS 1. Remove old wires and check with volt meter. Master switch ON, heater OFF. One of the wires to the old heater will be HOT. This wire should be connected to terminal #1 on the new heater. 2. With switches off, use OHM meter to identify ground wire and connect to terminal #5 on the new heater terminal strip. Tape off the remaining old wires as they will not be used. 3. The new combustion air blower red wire should be connected to terminal #1 and black to ground. 4. If aircraft has an old mechanical thermostat, it may be removed along with it's push-pull cable. See instructions of the new electronic adjustable duct switch CD21253 in the installation instructions, item 2D.