First Co 12MB-HW Installation, Operation & Maintenance Instructions Manual Download Page 3

VMB-HW Fan Coil can be installed for upflow and horizontal-left applications as factory shipped.  Units can be installed for

horizontal-right applications with field modifications.

CAUTION: 

 Extreme caution must be taken that no internal damage will result if screws or holes are drilled

into the cabinet.  Failure to follow this CAUTION could result in product or property damage and minor

personal injury.

-- Upflow Installation

Unit must be mounted on a field supplied return plenum that is open or ducted with return air.  Only use return-air opening

provided in the bottom of the unit.  All return air must pass through the bottom of the unit and A-coil. 

 

(See Figure 2.)

-- Horizontal Installations

Be sure installation complies with all applicable building codes that may require installation of a secondary condensate pan.

The VMB-HW Fan Coil unit is factory assembled for horizontal left side down application without any modification re-

quired.

1.  Arrange support for unit by setting it in or above secondary condensate pan.

2.  When suspending unit from ceiling with metal support straps extreme care should be taken that no internal damage

will result if screws are drilled into the cabinet.

CAUTION:  

The unit should be leveled in such a way that there is slope toward the condensate drain nipple

to assure positive drainage.  Failure to follow this CAUTION could result in  product or property damage.

-- Horizontal Right Conversion

To convert unit for horizontal right side down installations:

1.  Remove blower and coil panels.

2.  Remove angle bracket holding top of horizontal drain pan.

3.  Remove horizontal drain pan and A-coil assembly.

4.  Flip horizontal drain pan over to right side and reinstall horizontal drain pan and A-coil into cabinet.

5.  Secure forward edge of horizontal drain pan with angle bracket.

6.  Replace blower and coil panels.

7.  Unit should be leveled in such a way that there is slope toward the condensate drain nipple to assure positive

drainage.

Figure 2 - Typical Unit Configuration

FIELD SUPPLIED

RETURN PLENUM

FIELD SUPPLIED

SUPPLY DUCT

POWER ENTRY OPTIONS

(LOW VOLTAGE ENTRY 

OPPOSITE SIDE)

VERTICAL POSITION

CONDENSATE DRAIN

FILTER ACCESS

PANEL

HORIZONTAL POSITION

LEFT SIDE DOWN

CONDENSATE DRAIN

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Summary of Contents for 12MB-HW

Page 1: ...al for personal injury Understand the signal words DANGER WARNING CAUTION and NOTE These words are used with the safety alert symbol DANGER identifies the most serious hazards which will result in sev...

Page 2: ...or brazing to the unit it is recommended to have a fire extinguisher readily available When soldering close to valve packages or other components heat shields or wet rags are required to prevent damag...

Page 3: ...condensate pan 2 When suspending unit from ceiling with metal support straps extreme care should be taken that no internal damage will result if screws are drilled into the cabinet CAUTION The unit sh...

Page 4: ...ing label for proper field high and low voltage wiring Make all electrical connec tions in accordance with NEC and any local codes or ordinances that may apply Use copper wire only The unit must have...

Page 5: ...r piping prior to connection to water coils to remove debris Use wet cotton rags to cool valve bodies when soldering Open all valves midway for hand valves manually open on motorized valves prior to s...

Page 6: ...inal 1 1 8 OD The hot water supply to the fan coil will be on the right when facing the fan coil upright and from the front All piping between the water heater and fan coil unit should be copper and s...

Page 7: ...roper drainage CAUTION Shallow running traps are inadequate and DO NOT allow proper condensate drainage See figure 6 Failure to follow this CAUTION could result in product and property damage NOTE If...

Page 8: ...requires servicing or water damage will occur Install traps in the condensate lines as close to the coil as possible Make sure that the outlet of each trap is below its connection to the condensate pa...

Page 9: ...to modify its operation to a pre programmed table of airflows See Table 1 Airflows are based on the system size or mode of operation and those airflows are modified in response to other inputs such as...

Page 10: ...Mild Humid Climates the motor is programmed with ramp time and speed to achieve dehumidification on cooling start up thus allowing more moisture to collect and drain from the coil The off cycle delay...

Page 11: ...et point and humidity is above humidity set point if dehumidistat is installed thermostat closes circuit R to G and R to Y1 and dehumidistat opens R to HUM The fan coil delivers airflow which is appro...

Page 12: ...ltage is present check the transformer 2 Check all plugs and receptacles for any deformation which could cause loose connections Be sure plugs are fully seated 3 Verify that approximately 120VAC is pr...

Page 13: ...rom the motor These signals will start the motor Dehumidify 24VAC is present with a call for no dehumidication Pin on 16 Pin Connector Signal on pin with Screw Terminal Jumpered to R 1 Common 2 W W1 H...

Page 14: ...oard is bad D Verify MotorWinding Section Before proceeding with module replacement check the following to ensure motor winding section is functional With control module removed and unplugged from the...

Page 15: ...an as required 5 Inspect electrical connections for tightness and controls for proper operating each heating and cooling season Service as required WARNING As with any mechanical equipment personal in...

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