Daikin Furnace Installation Manual

The Daikin Furnace is a high-efficiency residential heating system designed for reliable performance and energy savings. This manual covers essential information for the safe and proper installation, setup, operation, and maintenance of your Daikin furnace. Below are key sections covering safety precautions, installation procedures, initial setup, specifications, controls, wiring, startup, maintenance, regulatory compliance, and troubleshooting.

1. Features at a Glance 2. Safety Precautions 3. Pre-Installation Requirements 4. Specifications 5. Installation Procedures 6. Electrical Wiring 7. Venting and Combustion Air 9. Initial Startup & Commissioning 10. Control Settings & Operation 11. Maintenance Schedule 12. Troubleshooting

Features at a Glance

Key components: High-efficiency heat exchanger, multi-speed blower motor, electronic ignition system, integrated control board, flame sensor, pressure switches, vent and intake connections, filter access panel, and diagnostic LED.

Feature	Description
Heat Exchanger	Stainless steel or aluminized steel construction for durability and efficiency
Blower Motor	ECM or multi-speed PSC motor for quiet operation and adjustable airflow
Ignition System	Hot surface or intermittent pilot ignition for reliable startup
Control Board	Microprocessor-based for system monitoring, diagnostics, and communication
Flame Sensor	Ensures flame presence during operation for safety
Pressure Switches	Verify proper venting and air pressure before ignition
Vent/Intake Connections	PVC piping options for direct vent (sidewall or roof)
Filter Access	Easy-access panel for standard 1" or 4" media filters
Diagnostic LED	Flashing code indicator for troubleshooting
Gas Valve	Modulating or two-stage for precise temperature control

Safety Precautions

Read all instructions before installation. Failure to follow safety guidelines can result in fire, explosion, carbon monoxide poisoning, electrical shock, or death.

Turn off electrical power and gas supply before servicing.
Install furnace in accordance with local codes, NEC, NFPA 54/ANSI Z223.1, and manufacturer instructions.
Ensure adequate combustion air and proper venting to prevent CO buildup.
Use only approved materials for gas piping and electrical connections.
Verify furnace input rate matches gas supply and manifold pressure.

WARNING! Installation must be performed by a qualified technician. Improper installation can void warranty and create hazardous conditions.

Pre-Installation Requirements

Before installation, verify site conditions and gather necessary tools and materials.

Location: Install in dry, clean area with sufficient clearance for service (typically 24" front, 6" sides, 6" rear, 6" above).
Combustion Air: Ensure adequate fresh air supply per code; consider direct vent or sealed combustion.
Venting: Plan vent and intake pipe routing (PVC, CPVC, or ABS per model); maintain proper slope and support.
Gas Supply: Confirm gas type (natural or LP); size pipe per length and BTU input.
Electrical: Dedicated 120V circuit; proper grounding; thermostat wiring.
Ductwork: Size return and supply ducts per furnace capacity; seal all joints.

CAUTION! Do not install in corrosive atmospheres or where flammable vapors are present.

Specifications

Model Series: Various (e.g., DG9, DV, DM).
Input BTU/h: 40,000 to 120,000 BTU (natural gas or LP).
Efficiency (AFUE): Up to 98%.
Blower Capacity: Adjustable CFM for cooling and heating modes.
Electrical: 120V, 60Hz, 15A circuit; includes 3-5A fuse on control board.
Gas Connection: 1/2" NPT typical; verify with model.
Vent/Intake Size: 2" or 3" PVC depending on length and BTU.
Dimensions (HxWxD): Varies by model (approx. 48"x21"x26").
Weight: 100-150 lbs.
Operating Temp Range: -30°F to 150°F ambient.

Installation Procedures

Follow step-by-step installation sequence. Use two people for handling.

Position furnace: Place on level, solid base (pad or concrete). Ensure vertical alignment.
Connect ductwork: Attach supply and return plenums; seal with mastic or foil tape.
Install gas piping: Use black iron or CSST; include sediment trap, shutoff valve, and union.
Pressure test: Test gas line at 14" WC for 10 minutes; no drop indicates no leaks.
Vent/Intake piping: Run PVC pipes per manual; maintain 1/4" per foot slope toward furnace.
Secure furnace: Use straps or brackets if required by seismic zone.

Tip: Check local codes for required clearances to combustibles and vent termination distances.

Electrical Wiring

Connect power, thermostat, and optional accessories.

Disconnect power at main panel.
Run 120V supply to furnace junction box; connect L1, L2, ground.
Connect thermostat: R (24V hot), W (heat), G (fan), C (common).
For AC or humidifier: Connect Y (cool) and accessory terminals.
Verify low-voltage polarity; secure all connections.
Install door safety switch; ensure door closes completely.

WARNING! Incorrect wiring can damage control board. Refer to wiring diagram on unit.

Venting and Combustion Air

Proper venting is critical for safe operation. Use only approved materials.

Direct vent (2-pipe): Separate intake and exhaust; terminate per manual (typically 12" above grade, 12" from openings).
Concentric vent: Combined intake/exhaust pipe; follow specific termination clearances.
Pipe supports: Support every 3-4 feet; use appropriate hangers.
Sealing: Use PVC cement on all joints; ensure no leaks.
Combustion air: If using indoor air, provide two permanent openings per NFPA 54.

CAUTION! Do not undersize vent pipes or exceed maximum length. Condensate can freeze in cold climates.

Initial Startup & Commissioning

After installation, perform startup sequence and verify operation.

Open gas shutoff valve; check manifold pressure (3.5" WC natural gas, 10" WC LP).
Set thermostat to heat mode; raise setpoint above room temperature.
Observe ignition sequence: inducer on, pressure switch closes, igniter glows, gas valve opens, flame sensed.
Check flame: Blue, stable; no lifting or yellow tips.
Measure temperature rise: Supply vs. return air (typically 35-65°F). Adjust blower speed if needed.
Verify venting: Use combustion analyzer to check CO and O2 levels.
Test safety controls: Simulate failures (block vent, disconnect flame sensor) to ensure shutdown.

WARNING! Never bypass safety devices. Always complete combustion analysis.

Control Settings & Operation

Access settings via control board dip switches or service pins.

Dip Switch Settings: Blower speeds (heating/cooling), gas type (natural/LP), single-stage vs. two-stage, thermostat type (conventional vs. communicating).

LED Codes: Steady = normal operation. Flashing = fault code (refer to chart on door).

Thermostat: Program schedules for energy savings; set fan to AUTO or ON.

Filter Reminder: Reset after filter change (if equipped).

Maintenance Schedule

Regular maintenance ensures efficiency and longevity.

Monthly: Check filter; replace if dirty.
Annually (before heating season): Professional inspection and cleaning.
Tasks: Clean flame sensor, check heat exchanger for cracks, clean blower wheel, inspect vent system, verify gas pressure and combustion, lubricate inducer motor (if required), check electrical connections, test safety controls.
Condensate Drain: Flush with water/vinegar; ensure trap is full and line clear.

CAUTION! Turn off power and gas before any maintenance.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	No power, door switch, thermostat	Check circuit breaker, door closure, thermostat settings/batteries.
No heat (blower runs)	Gas supply, igniter, flame sensor	Verify gas valve on; check igniter for glow; clean flame sensor.
Short cycling	Dirty filter, high limit, vent blockage	Replace filter; check airflow; inspect vent for obstructions.
Lockout (flashing LED)	Ignition failure, pressure switch	Decode LED flashes; check gas pressure, inducer, pressure switch tubing.
Unusual noises	Loose panels, blower issues	Tighten screws; inspect blower wheel for debris; check motor mounts.
Condensate leak	Clogged drain, broken trap	Clear drain line; ensure trap is properly installed and sealed.

Reset: Power cycle (turn off for 30 seconds) to clear lockout. If problem persists, call technician.

Service: Contact Daikin authorized dealer or 1-855-344-2546; www.daikincomfort.com