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lp-445-r4 Rev. 006 Rel. 027 Date 7.21.20
35
WIRING CONNEC TION DIAGRAM
500, 700 and 850
POWER
SWITCH
SUPPLY
RETURN
X4-13
X8-1
X4-12
X8-2
X4-7
X4-17
MAN RESET
HIGH WATER
TEMP
AUTO RESET
HIGH WATER
TEMP
HIGH GAS
PRESSURE
X8-5
X8-7
X4-4
X4-18
X4-20
LOW WATER
LEVEL
CONDENSATE
FULL
LOW GAS
PRESSURE
OUTDOOR
**** DHW TANK
10
11
12
13
14
15
0-10 VOLT
+
-
FLUE
ECO
X4-5
X4-6
X4-16
X4-15
16
17
TT TERMINALS
J3-3
J3-4
J3-5
J4-3
J4-4
RS485 BUS
RS485 BUS
X4-8
X4-9
MOTOR
BLOWER
24VAC <12VA
GAS VALVE
X5-4
X5-3
RELAY
X4-9
X4-8
DETAIL "A"
BLOWER
MOTOR
X-2
RIBBON CABLE
ORANGE
SPARK CABLE TO SPARK ELECTRODE
TEXT DISPLAY
X4-11
120 VAC
LINE
F1
CR1
J4-4
CONDENSATE
RECEPTICAL
FLOW SWITCH
FLOW SWITCH FOR VWH APPLICATION ( OPTIONAL FOR STANDARD BOILER APPLICATION )
LOW WATER LEVEL APPLICATION FOR STANDARD BOILER ONLY ( NOT FOR VWH )
*
*
*
**
*
X6-5
FLAME RECTIFICATION
PROBE
BVPS
FUSE
THERMAL
X5-4
926
CONTROL
X4-5
X4-6
X4-16
X4-15
X5-3
X8-10
X8-4
X4-19
X8-9
VALVE
FLAPPER
J5-6
J5-7
X4-1
J5-9
J5-8
X8-6
J5-10
X8-3
X4-10
J5-3
J5-4
X8-8
J5-2
X4-2
X4-14
J5-1
J6-4
X5-7
X5-8
J6-6
J6-5
X5-5
F2
4
5
2
NEUT
GND
F3
120V
J7-1
J7-3
J6-1
X6-1
J8-3
J8-4
J8-1
G
H
6
1
3
DHW
PUMP
BOILER
PUMP
N
8
7
9
CR1
CR1
ALARM
***
***
MAX 3 AMPS/120 VAC. USE CONTACTOR IN PLACE OF PUMP FOR GREATER DRAW.
***
120V
GAS VALVE
X4-3
J5-5
J6-3
X6-4
J6-2
X6-2
B
A
JUMPER IN 'B' POSITION
FOR ALL MODCON UNITS
TEMP LIMIT
SWITCH
OPTIONAL
UL353
LWCO
FOR DOUBLE STACK UNITS - SUPPLY MANIFOLD SYSTEM SENSOR BOTTOM BOILER
****
REAR
FRONT
SEE DETAIL "A" FOR 120V GAS
VALVE WIRING APPLICATION
Figure 27 - Internal Connection Diagram
Part 8 - Gas Connections
Failure to follow all precautions could result in fire, explosion, severe
injury, or death.
It is very important that you are connected to the type of gas noted
on the rating plate. “LP” for liquefied petroleum, propane gas, or
“NG” for natural or city gas. Do not do a gas conversion without
an approved gas conversion kit. Prior to turning the gas on, all gas
connections must be approved by the local gas supplier or utility, in
addition to the governing authority.
A gas conversion kit comes with 500 model boilers ONLY. Field
conversions ARE NOT ALLOWED on 700/850 models. A properly
calibrated combustion analyzer must be used to verify proper
combustion. Failure to follow the above instructions could result in
property damage, serious injury, or death.
The gas supply shall have a minimum of no less than 3.5” water column,
a maximum inlet pressure of no greater than 14” water column (350
mm), and ½ pound pressure (3.5 kPa). The entire piping system, gas
meter, and regulator must be sized properly to prevent excessive
pressure drop (greater than 0.5” WC) as stated in the National Fuel
Gas Code. This information is listed on the rating plate.
UL recognized fuel gas detectors are recommended in all enclosed
propane and natural gas applications where there is a potential for
an explosive mixture of fuel gas to accumulate. The installation of
these detectors should be made in accordance with the detector
manufacturer’s recommendations, and/or local laws. Failure to
install fuel gas detectors in these applications could result in fire,
explosion, property damage, severe personal injury, or death.