Daikin Rooftop Unit MPSH05

Warning: Only trained personnel should perform this procedure.

Reference Figure 44 for location of the speed tap block on the blower

Furnace control access panel removed

See Figure 45 for location of the integrated furnace control board

Reference Figure 44 and Figure 46 for the proper location of the red and black wires on the speed tap block and on the furnace integrated control board to obtain the speed tap you have chosen

Power supply to unit must be disconnected before making field connections

To avoid electrical shock, personal injury or death, be sure to rigorously adhere to field wiring procedures regarding proper lockout and tagout of components

It is recommended that at the beginning of each cooling season a qualified installer or service agency inspect and clean the cooling section of this unit

The following areas should be addressed:

DANGER: Power supply to unit must be disconnected before making field connections. To avoid electrical shock, personal injury or death, be sure to rigorously adhere to field wiring procedures regarding proper lockout and tagout of components.

DANGER: Holes in the exhaust transition or heat exchanger can cause toxic fumes to enter the building. The exhaust transition or heat exchanger must be replaced if they have holes or cracks in them. Failure to do so can cause carbon monoxide poisoning resulting in personal injury or death.

The unit’s furnace should operate for many years without excessive scale build-up in flue passageways. However, it is recommended that a qualified installer, service agency, or the gas supplier annually inspect the flue passageways, the exhaust system and the burners for continued safe operation, paying particular attention to deterioration from corrosion or other sources.

Turn OFF the electrical power to the unit and set the thermostat to the lowest temperature

Shut OFF the gas supply to the unit either at the meter or at manual valve in the supply piping

Remove the furnace controls access panel and the control box cover. Disconnect the gas supply piping from the gas valve

Disconnect the wiring to the induced draft blower motor, gas valve, flame sensor, and flame roll-out control, and ignitor cable. Mark all wires disconnected for proper reconnection

Remove the screws (4) connecting the burner tray to the heat exchanger mounting panel. Remove the burner tray and the manifold assembly from the unit

Warning: This procedure requires trained personnel with PPE!

Supply and manifold pressure taps are located on the gas valve body 1/8\ N.P.T. and on the manifold"

Use a properly calibrated manometer gauge for accurate gas pressure readings

Only small variations in the gas flow should be made by means of the pressure regulator adjustment

Furnaces functioning on LP gas must be set by means of the tank or branch supply regulators

Note: The blower motor and induced draft blower motor are prelubricated by the manufacturer and do not require further attention.

A qualified installer, service agency or the gas supplier must periodically clean the motors to prevent the possibility of overheating due to an accumulation of dust and dirt on the windings or on the motor exterior.

The motor depends upon sufficient air flowing across and through it to prevent overheating.

Is there sufficient air flow across and through the motor?

Sign off on the motor maintenance