Nordair Niche DH2 150, Инструкция по установке, наладке и обслуживанию, Страница: 24 / 26

Note Replacement of components
should only be carried out by a
competent person.
Isolate electrical and gas supplies
before replacement of parts. Check for
gas soundness after replacing gas
carrying components. Access for
replacement of the main burner
assembly, ignition electrode, flame
electrode, fan, motor, drive belts, is via
the access doors in the fan section.
Inadvertent substitution or replacement
of similar components, particularly
those with plug-in bases, could cause
a hazard.
Main burner assembly
Disconnect main gas supply union and
pilot gas supply, HT cable and flame
rod connections. Unbolt burner straps
from the burner supports and remove
assembly from heater. If necessary,
replace damaged sections as required,
re-join flanges using Hermetite,
Plasticoll X10G joining compound.
Replace burner assembly in reverse
order to removal. Check operation and
combustion as detailed in the
Commissioning Instructions.
Ignition electrode
Isolate electrical supply, remove HT
cable, unscrew ignition electrode from
burner body, ensure electrode has
3mm spark gap, replace with new and
reconnect HT cable, and protective
boot.
Ignition transformer
Isolate electricity supply, unbolt ignition
transformer. Disconnect cable from
terminal block and remove and replace
ignition transformer. Reconnect
cables.
Flame electrode
Isolate electrical supply, remove cable
from flame electrode, unscrew old rod
and replace with a new one, bending
the probe through 45
˚
so that the probe
runs parallel to the burner plates. It
will be necessary to straighten the old
probe prior to unscrewing from the
burner.
Ambi-Tec controller
Isolate electrical supply at heater.
Remove Ambi-Tec front cover,
discount wires from terminal rail
ensuring cable/terminal numbers are
recorded. Remove 5WA multicode
cable from the base and unscrew base
plate from wall. Refit new Ambi-Tec
controller, ensuring all wiring
connections are correct. The Ambi-Tec
controller will require reprogramming
and this should be carried out by a
Nordair Niche Engineer.
Modulating gas valve control unit
Isolate electric supply, unbolt motor
clamp from valve spindle and remove
motor from motor mounting bracket,
replace and re-connect. Care should
be taken not to move the valve
spindle, as this will alter the low fire
setting and will require
re-commissioning.
Gas train components
Isolate gas and electricity supply,
disconnect electrical connections to
valves and modulating valve motor unit.
Unscrew unions on gas train, replace
components where necessary using
approved thread sealing compound,
re-fit and tighten unions. Gas train
should be leak tested and
recommissioned.
Drive belts
Access is via the twin access doors in
the fan section. Loosen motor
adjusting screw, replace belts and
re-tension.
Active duct sensor
Isolate electrical supply, remove cover
from sensor, unscrew terminals,
remove cable, remove fixing screw and
withdraw. Refit new duct sensor and
refit in reverse order. Potentiometer
will require resetting, this should be
carried out by a Nordair Engineer.
Room sensor
Isolate electrical supply, unclip room
sensor, unscrew terminal, and remove
cable. Refit new room sensor and refit
in reverse order.
Air differential pressure switch
Isolate main electrical supply, remove
cover of pressure switch, terminal box.
Disconnect electrical wires, remove
sensing tubes and unbolt pressure
switch from mounting bracket, replace
the switch, re-connect the sensing
tubes, re-connect the electrical supply.
Recommission the differential pressure
switch by setting to the pressure switch
to 75% of the measured differential
pressure between pressure points P8
and 9.
Control panel components
Burner programmer
Unscrew body from terminal base and
replace.
Relays
Unplug body and replace.
Motor MPCB
Remove and replace, replace amp trip
setting.
Control MCB
Remove and replace.
Overheat thermostat
Isolate electrical supply, remove the
cover, disconnect wiring, unscrew from
duct/casing and withdraw. Fit
replacement thermostat reconnect
wiring and reset to 85
˚
C for the DV
range and 75
˚
C for the DH range, then
replace cover.
Replacement instructions