Cambridge Air Solutions M Series, Техническое руководство

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Cambridge Air Solutions. 92 M-Series Technical Manual
EXHAUST FAN CONTACT (EFC)
The exhaust fan contact is an auxiliary dry contact that
is mechanically interlocked to operation of the heater’s
motor starter and is provided with terminals located in
heater’s electrical enclosure. The dry contact is typically
wired into an exhaust fan control circuit to activate the
exhaust fan as a slave to the make-up air heater.
FLAME SAFEGUARD RELAY (FSR)
The flame safeguard relay supplies
24 Volts AC to the igniter for 4
seconds prior to the gas valve
being energized. If the burner
does not light (flame is not
established within 7 seconds), this
control will lock out. If flame signal
is lost during burner operation, the control will allow one
retry for ignition.
FLAME ROD (FR)
The flame rod senses the
presence of flame, and signals the
flame safeguard relay. The
presence of flame is detected by
the flame rectification of the AC
signal that is supplied to the
flame rod, thus creating the DC response. The resulting
current flow produced can be measured with a DC
microammeter. The reading should be steady and
between 2.0 and 6.0 microamps (
m
A).
FUSE BLOCK
The fuse block provides line fusing for
branch circuit protection. It is wired in
conjunction with the non-fused
disconnect switch.
HIGH and LOW GAS PRESSURE SWITCH
(HGP, LGP)
The high gas pressure switch is a manual reset
safety device to lock out the burner operation
should large gas pressure fluctuations
occur. The high gas pressure switch
should be set at 25% above manifold gas
pressure. The adjustment screw is located
under the top plate.
HIGH PRESSURE REGULATOR (HPR)
The high pressure regulator is required
when the gas supply pressure exceeds
the nameplate rating for the heater.
The high pressure regulator assembly
is also furnished with a high gas
pressure manual shut-off valve and a tap
for measuring the upstream gas pressure. The high pressure
regulator is a positive lock-up type regulator which must
be vented to the outdoors. It is sized according to the gas
supply pressure and the capacity requirements of the heater.
HIGH TEMPERATURE LIMIT (HL)
The high temperature limit opens when
the discharge air temperature exceeds
150˚F. This limit must be manually reset.
INCLINED MANOMETER
An inclined manometer with a range of
-0.1 to 1.0 inch WC is provided on each
heater with manual profile damper
adjustment to indicate the pressure drop
across the burner profile plate. The
pressure drop should be set without the
burner operating (blower only) at 0.68
inch WC for natural gas applications
and 0.90 inch WC for LP applications. If the heater is
supplied with a filter section or filters in the rainhood,
increase the manometer reading to 0.72 inch WC for natural
gas and to 0.94 inch WC for LP gas heaters.
DIFFERENTIAL PRESSURE SWITCH/GAUGE
A differential pressure switch/gauge is
available as part of the Automatic
Profile Adjust system to control the
pressure drop across the burner profile
plate. The differential pressure switch
drives a Profile Damper Adjust Motor
to maintain approximately 0.68 inch
WC for natural gas applications, or approximately 0.90
inch WC for LP applications.