Electrical wiring (milli-volt), Caution – Monessen Hearth DSSNVMB User Manual
Page 13
12
46D0550
46D0550
13
ELECTRICAL WIRING (MILLI-VOLT)
The milli-volt valve is a self-powered combination gas control THAT DOES NOT REQUIRE 110 VAC TO OPERATE.
Label all wires prior to
disconnection when
servicing controls. Wiring
errors can cause improper
and dangerous operation.
Verify proper operation
after servicing.
CAUTION
On/Off
Switch
On/Off
Switch
ODS
Pilot
Wall
Switch
Optional Wall
Switch, Wall Thermostat,
Thermostat Sensor or
Remote
ODS Pilot
Millivolt
Valve
Spade Terminal
3
1
2
CONNECTION
1 = TP
2 = TP, TH
3 = TH
Figure 7 - Wiring Diagram
CONNECTING OPTIONAL WALL SWITCH OR THERMOSTAT
1. Use 18 awg, two-wire cable, 15 feet maximum length.
2. At one end of the cable, connect both wires to the wall switch or thermostat. At the other end, connect one wire to
TP/TH and one wire to TH, or connect the wall switch/thermostat to the two male (0.25") terminals on the left side of
the unit. The color of the wires does not matter.
CONNECT
CHECK TO METER THERMOSTAT METER
TEST TEST LEADS TO CONTACTS READING
TERMINALS SHOULD BE
A COMPLETE 2 & 3 CLOSED MINIMUM
SYSTEM 175mv
B THERMOPILE 1 & 2 OPEN 500mv
OUTPUT OR MORE
A. COMPLETE MILLIVOLT SYSTEM CHECK
("A" Reading - Thermostat contacts CLOSED - Control Knob “ON” - Main Burners should turn ON)
a. If the reading is more than 175 millivolts and the automatic valve still does not come on - replace the valve.
b. If the closed circuit reading ("A" reading) is less than 175 millivolts, determine cause for low reading - proceed as
follows:
B. THERMOPILE OUTPUT READING CHECK
(“B” Reading - Thermostat contacts OPEN - Main burner OFF)
Check gas pressure to the unit. If gas pressure is within minimum and maximum on data plate, then replace pilot. 500 millivolts
minimum. If the minimum millivolt reading is not obtainable, replace pilot.
CHECKING SYSTEM OPERATION
The millivolt system and individual compo-
nents may be checked with a millivolt meter
having a 0-1000mv range. Conduct each
check shown in chart by connecting meter
test leads to terminals as indicated.
Switch