General Maintenance - Modine HDS Manuel D'installation

SERVICE / MAINTENANCE / TROUBLESHOOTING
WARNING
When servicing or repairing this equipment, use only factory-
approved service replacement parts. A complete replacement
parts list may be obtained by contacting the factory. Refer
to the rating plate on the appliance for complete appliance
model number, serial number, and company address. Any
substitution of parts or controls not approved by the factory
will be at the owner's risk.
CAUTION
1. Service or repair of this equipment must be performed by
a qualified service agency.
2. Do not attempt to reuse any mechanical or electrical
controllers which have been wet. Replace defective controller.
To check most of the possible remedies in the troubleshooting
guide listed in Table 20.1, refer to the applicable sections of the
manual.

General Maintenance

The unit and venting system must be checked once a year by
a qualified service technician.
All installation and service of these units must be
performed by a qualified installation and service agency.
Before any service, BE SURE TO TURN OFF GAS AT THE
MANUAL SHUT-OFF VALVE AHEAD OF THE COMBINATION
GAS CONTROL AND TURN OFF ALL ELECTRIC POWER TO
THE HEATER.
Table 20.1 - Troubleshooting
TROUBLE
Unit does nothing
LED light off or
flashing
Unit starts but does
not ignite
Unit goes through cycle
but the burners go out
in less then 10 seconds
Air circulating fan
inoperable
20
POSSIBLE CAUSE
1. Power supply is off
2. No 24V power to thermostat
3. Thermostat malfunction
4. LED flashes
5. Blown fuse on control board
6. Defective control
1. Blown fuse on control board
2. Multiple causes
1. Main gas is off
2. Air in gas line
3. Main or manifold gas pressure
4. Check gas valve switch
1. Reversed main power polarity
2. Unit not grounded
3. Flame not sensed
1. Loose connections
2. Defective control board
3. Defective fan motor
1. Service air moving components annually.
a. Check fan for fit on motor shaft and for damage to blades.
2. Keep unit free from dust, dirt, grease, and foreign matter,
paying particular attention to:
a. Combustion air inlets.
b. Burners and burner orifices. Turn off gas ahead of the
combination gas control and shut off electric power to
the heater. Remove the access panel, open the union
on the gas line, and disconnect the igniter and sensor
wires. Remove the screws that attach the burner tray to
the header plate and remove the burner tray and manifold
assembly from the heater. Carefully clean the burners
with a wire brush or other suitable means. Replace any
damaged or deteriorating burners or orifices. Install the
burner assembly back on to the header making certain
that all screws, pipes and electrical connections are tight.
CAUTION: Be careful when handling the igniter and flame
sensor.
3. Inspect the flame sensor and igniter for deterioration and/or
cracks.
4. Verify that the burners are touching each other at the
carryover points. This will ensure flame carryover from burner
to burner.
a. Clean exterior of heat exchanger tubes.
b. Fan blade.
5. Check wiring for possible loose connections.
6. Controls – The gas valves and piping should be checked
annually for general cleanliness and tightness. The gas
controls should be checked to insure that the unit is
operating properly. See control instruction sheets furnished
separately with the unit heater.
7. Power exhaust assembly/motors – The power exhaust
motor bearings have been lubricated for long life and do not
require additional lubrication. In dirty atmosphere, it may be
desirable to clean the motors and blower housing and blow
out the cooling air passages of the motor with compressed air.
8. Perform periodic cleaning of inlet and vent terminal screens.
POSSIBLE REMEDY
1. Turn on main power
2 a. Check control transformer
b. If failed transformer - check thermostat wire gage and length
3 a. Verify wire connections to R&W terminals only
b. Check / replace thermostat
4. Check LED flash code
5. Replace fuse
6. Replace control
1. Replace fuse
2. Control board LED flash codes vary with control type. A decal is
installed in the unit giving a brief description of the applicable codes
for your heater. For more detail, see the control board data sheet
included with the unit.
1. Open manual gas valve
2. Purge gas line
3. Set gas pressures per manual instructions
4. Set gas valve switch to "ON" position
1. Black wire - HOT, White wire - NEUTRAL, Green wire - GROUND
2. Ground unit and verify quality of ground connection
3. Check flame sense probe and connection
1. Check all connections
2. Check control board data sheet and function
3. Check fan motor
6-584.11