Daikin DBC Series, Installation Instructions Manual

10

4.  Route thermostat wires from sub-base terminals 

to the unit. Control wiring should enter through the 

condenser panel opening or through curb indicated in 

“Electrical Entrance” figure. Connect thermostat and 

any accessory wiring to low voltage terminal block 

TB1 in the main control box.

NOTE:  Field-supplied conduit may need to be 

installed depending on unit/curb configuration. 

Use #18 AWG solid conductor wire whenever 

connecting thermostat wires to terminals on 

sub-base. DO NOT use larger than #18 AWG wire. A 

transition to #18 AWG wire may be required before 

entering thermostat sub-base.

NOTE: Refer to unit wiring diagrams for 

thermostat or remote sensor connections.

CIRCULATING AIR AND FILTERS

Ductwork

The supply duct from the unit through a wall may be 

installed without clearance. However, minimum unit 

clearances must be maintained (see “Clearances" section).  

The supply duct should be provided with an access panel 

large enough to inspect the air chamber downstream of 

the heat exchanger.  A cover should be tightly attached to 

prevent air leaks.

Ductwork dimensions are shown in the roof curb 

installation manual.

If desired, supply and return duct connections to the unit 

may be made with flexible connections to reduce possible 

unit operating sound transmission.

CONDENSATE DRAIN CONNECTION

Condensate Drain Connection

A 3/4" female NPT drain connection is supplied on the 

end of the unit and bottom of the drain pan for condensate 

piping.  An external trap must be installed for proper 

condensate drainage. Hand tighten drain fitting to the drain 

connection.

STANDARD

SIDE DRAIN

DRAIN PLUG

(FACTORY-INSTALLED)

Drain Pan (Side View) 

NOTE: 

Trap should be deep enough to offset maximum

unit static difference.  A minimum 4” trap is recommended.

Drain Plug

Roof Curb

See NOTE

Base Rail

Open Vent

2” Min

drain connection 

Install condensate drain trap as shown. Use 3/4" drain line 

and fittings or larger. Do not operate without trap. 

Horizontal Drain 

Drainage of condensate directly onto the roof may be 

acceptable; refer to local code. It is recommended that a 

small drip pad of either stone, mortar, wood or metal be 

provided to prevent any possible damage to the roof. 

Vertical Drain

To use the bottom drain connection, remove the drain plug 

from the bottom connection and install it in the horizontal 

connection.

Cleaning

Due to the fact that drain pans in any air conditioning 

unit will have some moisture in them, algae and fungus 

will grow due to airborne bacteria and spores. Periodic 

cleaning is necessary to prevent this build-up from plugging 

the drain. A non-chlorine cleaning agent must be used. 

STARTUP, ADJUSTMENTS, AND CHECKS

WARNING

HIGH VOLTAGE!

To avoid personal injury or death due 

to electrical shock, bond the frame 

of this unit to the building electrical 

ground by use of the grounding 

terminal provided or other 

acceptable means. Disconnect all 

power before servicing or installing 

this unit.