Midco RE32 - Manual (Page 4)

-4-
V ELECTRICAL
Installation wiring and grounding of the burner must conform to
local codes, or, in their absence in the United States to
National Electric Code, ANSI/NFPA No. 70-1 latest edition; in
Canada, to Canadian Electrical Code Part 1, CSA Standard
C22.1.
■ Use 14 gage copper wire for line voltage wiring. Be sure to
hook up to permanently live circuit. Provide a fused on-off dis-
connect switch carrying a minimum 3 amp fuse.
■ The frame of the burner should be well grounded. A terminal
is provided on the strip for positive grounding.
■ Confirm that the polarity is correct -- hot wire to strip terminal
1, neutral 2 -- and that the neutral line is not subject to induced
low voltage (check 2 to earth ground) from other equipment, as
that can cause the flame safeguard to malfunction.
■ Each installation must include suitable limit control(s).
Existing oil burner combination operating and limit controls are
normally NOT SUITABLE for gas burner use.
■ Set the thermostat heat anticipator for the total current draw
handled by the thermostat. The current draw of the Economite
24V operating circuit is 0.9 amps.
CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper
and dangerous operation. Verify proper operation after
servicing
.
10
130
200
275
300
300
TYPE OF
GAS
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
PROPANE
VI PIPING
CAUTION: The available gas pressure should be within
the limits shown in the SPECIFICATIONS section.
Excessive pressure will damage Combination Valve and
Regulator. If the supply pressure exceeds the 14.0" W.C.
maximum, a suitable intermediate main regulator rated for
main and pilot loads must be installed ahead of the Main
Manual Shut-Off Valve shown in Figure 7.
■ The burner gas supply piping should branch off from the
main line as close to the gas meter as possible. Do not connect
to the bottom of a horizontal section. Use new black pipe and
malleable fittings free of cutting and threading burrs or defects.
■ Provide a sediment trap, union and 1/8" pressure tap in
piping close to burner as shown in Figure 7.
■ Use pipe joint compound approved for use with Liquid
Petroleum Gases.
■ Piping must comply with local codes.
■ To obtain the maximum firing rate of 300 MBH, the gas
supply piping must be sized to provide a minimum of 4.0" W.C.
pressure to the inlet of the combination valve when the burner
and all other gas utilization equipment are on. For a firing rate
of 225 MBH or less, 3.5" W.C. inlet pressure is sufficient.
■ When selecting the burner supply pipe size per Table 2, the
permissible pressure drop must be based on the pressure
available at the inlet to the supply pipe branch line when all
other gas utilization equipment is on.
NOTE: If there is more than 1.0" W.C. differential in the inlet
pressure to the burner compared to when all other gas
utilization equipment is off, refer to Section IX, last paragraph.
CAUTION: Because it is difficult to accurately control
pressure during supply pipe leak test, it is recommended
that the Combination Valve be disconnected. Exposing the
Combination Valve to a pressure over 1/2 (14" W.C.) PSIG
will damage the valve and void all warranties.
DANGER: Explosion hazard. Do not use oxygen for
pressure testing. An explosion could occur during initial
start-up.
■ If the burner piping must be rearranged because of space
limitations, be sure to carry out the general arrangement shown
in Figure 7. Install the combination valve in any position except
up-side down.
■ When the burner is installed in the vestibule of jacketed
equipment, it is recommended that the combination valve be
left adjacent to the burner within the vestibule. Install the Main
Manual Shut-Off Valve in the piping outside the jacket of the
equipment.
TABLE 2: Supply Pipe Capacities in MBH
Capacities shown are for a total pressure drop of 0.3" W.C. For
higher permissible pressure drops, consult your fuel supplier.
Source: Gas Engineers Handbook-1974
CAUTION: Do not add any power consuming devices in
the low voltage circuit as it could overload the transformer.
Do not use Motor Relay to operate any external devices as
the extra load could damage the relay contacts.
NOTE: If any of the original wiring as supplied with the
conversion burner must be replaced, it must be replaced with
type TFF wire or its equivalent.
FIGURE 6 Wiring Diagram
PIPE
SIZE
1 Ъ 2
3 Ъ 4
1
1 1 Ъ 4
20
90
145
190
300
300
40
60
100
130
200
245
300
300
60
50
80
105
165
195
300
300
100
60
80
125
150
235
300
300
APPROX. CAPACITY-MBH
LENGTH OF PIPE
MV
PV
MV
PV
MV PV
GND
BURNER
24V
GND
24V
SENSE
MOTOR WITH INTERNAL
INTERLOCK SWITCH
COMBINATION
VALVE
SCHEMATIC
CONNECTION DIAGRAM
2
4
1
3
MOTOR RELAY
T T 1 2
GND
Y
BK
BL(Y)
W(BK)
TRANSFORMER
NEUTRAL
120/1/60
HOT
THERMOSTAT OR 24V OPERATING
CONTROL. IF NOT USED, JUMPER T-T SERIES CONNECT ALL 120V OPERATING
AND/OR LIMIT CONTROLS
FUSED DISCONNECT
BL
TERMINAL
STRIP
2 1
NEUTRAL
MOTOR
BK(W) BK
M I 4 2
HOT
120 V CONTROLS 120/1/60
W(BK) BK
Y BL(Y)
T(LEFT) T(RIGHT)
24V
THERMOSTAT OR 24V CONTROL
IF NOT USED, JUMPER T-T
M
1 3
MOTOR RELAY
SPST N.O. BL Y
R(Y)
INTERLOCK SWITCH
R(Y)
GROUND
BAR
BK
LEGEND
Y 24V
GND
24V
SENSE
SPARK
BK
SPARK ROD
SPARK ELECTRODE
SENSOR ROD
BL
BR
Y BK
BK
R(Y) R(Y)
W(BK)
(NOT USED)
SPARK
BK
WIRING AND
COMPONENTS:
TERMINALS:
Y
MV/PV
GND
S8600 ELECTRONIC CONTROL
MV
PV
MV
PV
Y
BL
BR
MV/PV MV/PV SENSE ROD
BR
Y
BL
Y
BL
BY MIDCO
BY INSTALLER
TERMINAL STRIP
COMPONENT
ELECTRONIC CONTROL
SPLICE
SPLICE
SPLICE