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COMBAT
®
CTU UNIT HEATERS INSTALLATION OPERATION AND SERVICE MANUAL
30
SECTION 13: SERVICING
13.1 Servicing Instructions
After commissioning, the heater will require
maintenance to be carried out annually. If the heater
is used in a dirty or dusty area, more frequent
maintenance may be necessary.
Installation, service and annual inspection of
heater must be done by a contractor qualified
in the installation and service of gas-fired heating
equipment.
WARNING
Cut Hazard
Turn off gas and electrical supply before maintenance.
Fan can start automatically at any time.
Failure to follow these instructions can result in severe
injury or product damage.
NOTE 1: After any maintenance or repair work
always test fire the heater in accordance with the
commissioning instructions
on Page 24, Section 11
through Page 27, Section 11.9 to ensure all safety
systems are in working order before leaving the
heater to operate. Minor faults may be traced by
using the troubleshooting charts
on Page 32,
Section 15 through Page 34, Section 15.4.
NOTE 2: Check all gas pipes and pipe joints to
ensure there are no cracks or gas leaks. Any cracks
in the pipes or pipe joints must be repaired.
NOTE 3: Inspect all suspended components and
hardware. Insure that they are in good condition,
properly tightened, and corrosion free.
13.2 Burner Maintenance
1. Open the hinged door and remove the burner
compartment cover.
See Page 36, Section
16.2.
2. Clean any deposits from the main burner which
may have formed in the injectors or venturi of
the burner.
See Page 36, Section 16.2.
3. Remove the ignition electrode and flame probe.
Check condition of ignition electrode and flame
probe. Clean off any deposits which may have
been formed, check condition of ceramic
insulators. Replace as necessary.
13.3 Fan/Motor Assembly Maintenance
The main fan bearings are permanently sealed and
do not need lubrication. Before cleaning, turn off gas
and electrical supply. Remove the fan(s) and use a
small brush or duster to clean the fan blades from
each side. Replace fan(s) when done.
13.3.1 For CTUB & CTUC Centrifugal Fan
Models
CTUB and CTUC models are fitted with thermally
protected three speed fans. The number of fans can
be found
on Page 41, Section 16.9 and the standard
air flow for each model can be found on Page 7,
Section 4.3.
For CTUC models, the fans may be accessed via
the removable panels in the top, bottom and sides of
the inlet spigot compartment as required.
Do not operate at higher speeds than the original
setting on the heater without prior consultation with
Roberts-Gordon.
The "HIGH" speed option is available to give the
normal required air flow against higher static
pressures and is not intended to be operated free
blowing or against low resistance. Use of the fans
under these conditions may cause the fan thermal
overload to operate and the fan thermostat to cycle.
All fans on a heater must be set to operate at the
same speed. For Models 50 - 115, they will be
switched using a fan relay built into the heater.
See
Page 40, Section 16.8.2.
13.4 Heat Exchanger Maintenance
The heat exchanger will remain clean unless a
problem has developed with combustion. Inspect the
heat exchanger. Look for signs of overheating at the
front tubes which may indicate burner over firing or
persistently low air flows.
13.5 Gas Control Valve Maintenance
No regular maintenance is required on these
devices. To change gas control valves,
See Page
35, Step 16.1 and Page 39, Section 16.5.
Do not repair or disassemble on site.
Replace faulty gas valves with genuine
ROBERTS GORDON
®
replacement parts.
13.6 Flue Fan
The flue fan should not require maintenance.
However, if the air pressure switch is causing burner
lockout, then remove the flue fan from the vent box
by unscrewing the screw at the outlet flange and the
flue fan mounting plate (
See Page 38, Section 16.4).
Ensure that the fan is free to run and that the fan
wheel is clean.