Operation - Honeywell RA890F Quick Manual

MOUNT RA890F
Disconnect power supply.
Remove relay cover (see Fig. 6) and position the RA890F
over the Q270A Subbase. Start all ten mounting screws and
tighten uniformly. These screws complete electrical circuits
(terminal 1 excepted) and hold the RA890F to the subbase.
As shipped from the factory, the RA890F is suitable for
use with interrupted or intermittent systems.
Fig. 6—RA890F and Q270A Subbase.
CAPTIVE
Q270A
MOUNTING
SUBBASE
SCREWS (10)
TERMINAL
BLOCKS
FLAME
CURRENT
TEST JACK
ARC GAP
PROTECTOR
PILOT LINK JUMPER WIRE
(0N BASE ALONGSIDE TEST JACK)
NORMAL OPERATION SUMMARY
Normal control operation is summarized below. Refer to
Fig. 5 for the internal schematic of the control.
1. Call for heat—Load relay pulls in after a slight delay
(flame relay must be out), ignition starts, pilot valve or burner
motor is powered. Safety switch heats.
2. Flame proved—Flame relay pulls in, safety switch
heater is de-energized, main valve is powered, ignition is cut
off (when used for interrupted ignition).
3. Call for heat satisfied—Load relay drops out, fuel
valves close, burner motor stops, and flame relay drops out.
LOAD RELAY (1K)
FLAME RELAY (2K)
SAFETY SWITCH
RESET
PUSHBUTTON
COVER
OPTIONAL
ALARM
CONTACT (3)
THUMBSCREW
M8766
FOR STANDING PILOT SYSTEMS ONLY
For use with standing pilot systems. Clip the pilot link
(wire loop in Fig. 7) as follows:
1. Turn off power.
2. Clip pilot link with side cutters. Do not twist off
because damage to circuit board can result. Remove any
pieces of the wire.
3. Be sure there is electrical clearance between the two
ends of the link, and from link ends to the test jack or relay
frame. Then restore power.
Fig. 7—Location of arc gap protector on
RA890F.
TEST
JACK
ARC GAP
PROTECTOR
NOTE: The pull-in of the load relay is delayed by a ther-
mistor with a nominal delay time of 3 to 5 seconds. The
thermistor is affected by ambient temperature, and the
delay time may be as short as 2 seconds when the
temperature is high and as long as 30 seconds when the
temperature is low. As the thermistor warms up, the 1K
relay might hum slightly before it pulls in. This is normal.
7
RA890F
INSTALLATION • OPERATION
PILOT LINK
M8767

Operation

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