Mars Troubleshooting Guide

UNHEATED MODELS
PROBLEM CAUSE SOLUTION
NO AIR BLOWING OUT OF
DISCHARGE NOZZLE		 - No power being supplied to the unit
from the electrical power source
- Circuit breaker is tripped
- Blown fuses on power supply
- Motor overload is open or tripped
- Motor contactor / relay defective
(if applicable)
- Failed switch		 - Confirm power source / check if in on position
- Reset circuit breaker
- Replace fuses
- Allow the motor to cool down; motor has auto reset internal overload; if unit is panel equiped, press reset
button on overload inside panel, or replace motor overload if overload remains tripped
- Check voltage to coil; check contacts to see if they are pulling in (see voltage reading chart).
- Replace or repair limit switch (see switch OIP)
MOTOR IS RUNNING BUT
FANS ARE NOT SPINNING		 - Loose or broken coupling (belt drive)
- Loose set screws on wheel hubs
- Fan spinning inside fan housing
- Broken fan hub		 - Replace or tighten coupling
- Tighten set screws on motor shaft flats
- Tighten fan on shaft or replace fan
- Replace fan wheels
ELECTRICAL CONTROLS
NOT WORKING WHEN
DOOR IS OPEN		 - Switch is in off position
- Door limit switch is not operating		 - Turn unit's switch to the on position
- Repair or replace door limit switch (see switch OIP)
UNIT WILL NOT TURN OFF - Door limit switch is permanently
closed or energized		 - Position the door switch in a manner that turns off the unit when the door closes, and turns on the unit when
the door opens. Only light pressure required.
LOW AIR FLOW - Discharge air vanes out of adjustment
- Obstuction on intake or discharge
- Power leads out of polarity
- Blower motor rotating below normal
speed
- Fan rubbing against housing
- Blower wheels clogged with dirt		 - Adjust vanes to proper position
(Refer to unit's O&M manual)
- Remove obstuction or move air curtain
- Switch power leads to correct polarity (3 phase models only)
- Apply proper voltage per unit requirement (see unit label) / Adjust adjustable motor speed knob (if
applicable)
- Free fan from housing
- Clean and remove dirt from blower wheels
EXCESSIVE AIR VELOCITY
AT DOOR OPENING		 - Nozzle out of adjustment and not
angled far out enough
- Air temperature too cold
- Air stream pushing air outside of the
building
** SEE AIR IS NOT HITTING THE FLOOR FOR FURTHER CAUSES		 - Adjust nozzle angle to outside
- Add auxilary heat to overcome wind chill
- Adjust discharge angle back into building
AIR NOT HITTING THE
FLOOR		 - Low air velocity
- Obstuction in the direction of air flow
- Negative building pressure		 - Adjust vanes to proper position or check installation height (Refer to O&M manual)
- Remove obstuction or move air curtain (Move out 3/8" for every 1" up from the door)
- Provide a make-up air system to relieve negative building pressure
UNEVEN AIR - Shaft rotating inside fan
- One motor not functioning		 - Replace fan or tighten fan on shaft
- Replace or repair motor
EXCESSIVE NOISE AND OR
VIBRATION		 - Loose or broken coupling (belt drive)
- Loose set screws on wheel hubs
- Fan spinning inside fan housing
- Broken fan hub
- Bearing end caps worn
- Damaged blower wheel
- Bearing end caps worn
- Balancing clips missing		 - Replace or tighten coupling
- Tighten set screws on motor shaft flats
- Tighten fan on shaft or replace fan
- Replace fan wheels
- Replace Bearing end caps
- Replace Blower Wheel
- Replace Bearing end caps
- Replace Blower Wheel
ELECTRICALLY HEATED MODELS
NO HEAT - Thermal overload stuck open or
tripped
- Switch is in "Heat" mode
- Thermostat out of adjustment
- Defective coils		 - Replace thermal overload or reset overload
- Check wiring or replace switch
- Adjust thermostat and check t-stat wiring
- Replace coils / fix air flow issue
LOW HEAT - Low ambient conditions
- Incorrect voltage
- Incorrect t-stat setting
- Poor location of t-stat
- Undersized electric coil
- Improper wiring size supplied to unit
- Improper Resistance or no continuity
across electric coil		 - Confirm temperature rise with submittal backpage
- Apply proper voltage to the unit per unit requirement (see unit label)
- Set t-stat to the proper setting
- Relocate t-stat to proper location away from discharge nozzle to sense the average room temperature
- Replace higher kw electric coil (check power requirements first)
- Check NEC code and replace wiring with proper wiring size
- Replace electric coil
EXTREME HEAT - Incorrect supply voltage
- Electric coils touching each other
- Deficient airflow across coil
- Improper t-stat setting
- Poor location of t-stat
- Airflow adjustment set too low		 - Supply proper voltage
- Spread electric coils apart
- Clear coil of restriction
- Adjust t-stat to proper setting
- Relocate stat to proper location closer to the discharge nozzle
- Adjust the adjustable speed control knob to a higher airflow
STEAM / HOT WATER HEATED UNITS
EXTREME HEAT - Low air flow across coil
- Dirty coil / fins clogged
- Water Flow Rate/ Steam Pressure too
high		 - Speed up fan or check wheel rotation
- Clean / remove dirt from coils
- Reduce steam pressure or water flow rate / pressure
LOW HEAT - Low ambient conditions
- Insufficient steam pressure / water
flow
- Inadequate condensation relief (steam
coil models only)
- Coil leaking		 - Check temperature rise with submittal back page
- Increase steam pressure / water flow to coil as
required
- Increase coil trap diameter
- Repair or replace coil
NO HEAT - Defective solenoid valve
- Inadequate water / steam pressure
- Fan Inoperable
- Door switch inoperable		 - Replace solenoid valve
- Increase steam / water flow
- Check fan operation (see "No Air Blowing Out Of
Discharge Nozzle")
- Check door limit switch function or replace door limit
switch
CONTROL PANEL FOR UNHEATED UNITS / HOT WATER AND STEAM HEATED
UNIT INOPERABLE - No Power being supplied to panel
- Circuit breaker is tripped
- HOA is in the "O" or Off position
- Contactor not energizing
- Contactor not energizing
- Contactor not energizing		 - Apply Power supply
- Flip circuit breaker to on positition
- Turn HOA switch on panel to "H" or ON position
- Turn HOA switch on panel to "A" or AUTO position when utilizing a switch to automatically turn the air curtain on when the door opens.
- Check fuses or replace fuses
- Push red button on Overload/Motor Protector to reset
- Check transformer or replace transformer
OVERLOAD (OL)/MOTOR


PROTECTOR(MP) TRIPPING		 - Amperage setting(s) too low on OL/MP during operation

- All motors are wired to one set of motor terminals and use only one OL/MP for overcurrent protection		 - Set the adjustable amperage dial to slightly above the actual running amperage for the unit. Having lower or higher actual voltage will affect the running amperage
and may fall beyond the standard range for the panel.
- Be ceratin that each motor is wired to separate terminals and do not share a common overload. For example: for a 2 motor unit; terminals 11, 21, 31 are for
motor 1 and terminals 12, 22, 32 are for motor 2.
LOW AIR FLOW - Power leads out of polarity
- Blower motor rotating below normal
speed		 - Switch power leads to correct polarity
- Apply proper voltage per unit requirement
(see unit label) / Adjust adjustable motor speed knob (if applicable)
See Voltage Readings Charts if further diagnosis is required
CONTROL PANEL FOR ELECTRICALLY HEATED MODELS
UNIT INOPERABLE - No Power being supplied to panel
- Circuit breaker is tripped
- On/Off switch is in the Off position
- Contactor not energizing
- Contactor not energizing		 - Apply Power supply
- Flip circuit breaker to on positition
- Flip the switch on panel to ON or up position
- Turn HOA switch on panel to "A" or AUTO position
when utilizing a switch to automatically turn the air
curtain on when the door opens.
- Check fuses or replace fuses
- Check transformer or replace transformer
LOW AIR FLOW - Power leads out of polarity
- Blower motor rotating below normal
speed		 - Switch power leads to correct polarity
(3 phase models only)
- Apply proper voltage per unit requirement
(see unit label) / Adjust adjustable motor speed knob (if applicable)
See Voltage Readings Charts if further diagnosis is required