Monessen Hearth DEB30 User Manual

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HIGH
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THE
RMOS
TAT
SE
TTING
A.  COMPLETE MILLI-VOLT SYSTEM CHECK 
   
(“A” Reading - Thermostat contacts CLOSED - Control Knob “ON” - Main burner should turn ON)
 
a.  If the reading is more than 175 milli-volts and the automatic valve still does not come on, replace the control.
 
b.  If the closed circuit reading (“A” reading) is less than 175 milli-volts, determine cause for low reading, proceed to 
Section B below. 
B.  Thermopile Output Reading Check 
(“B” Reading - Thermostat contacts OPEN - Main burner OFF)
 
1.  Check gas pressure to the unit. If gas pressure is within minimum and maximum on data plate, then check pilot 
voltage, 500 milli-volts minimum. If the minimum milli-volt reading is not obtainable, replace pilot.
 
 
 
CONNECT
 CHECK 
TO 
METER 
THERMOSTAT 
METER
 TEST 
TEST 
LEADS 
TO 
CONTACTS 
READING
  
 
TERMINALS 
 
SHOULD 
BE
 A 
COMPLETE  TP/TH 
and 
TH 
CLOSED 
MINIMUM 
  
SYSTEM 
 
 
175
 B 
THERMOPILE  TP 
and 
TP/TH 
OPEN 
MINIMUM
  
OUTPUT 
 
 
 
500
CHECKING SYSTEM OPERATION
The milli-volt system and individual com-
ponents may be checked with a milli-volt 
meter having a 0-1000 mV range. Conduct 
each check shown in chart below by con-
nection meter test leads to terminals as 
indicated.
ELECTRICAL WIRING (MILLI-VOLT)
OPERATION OF THERMOSTAT SENSOR
1. Follow millivolt lighting instructions on lighting plate attached to unit or in homeowner’s manual. 
2. With control knob in the “ON” position make sure the ON/OFF switch is in the “OFF” position. See Figure 24. 
3. The unit is now being controlled by the thermostat sensor. The sensor will now cycle the burners on and off. You can adjust 
how often the unit cycles by turning the control knob on the sensor. 
Figure 24 - Control Knob in “ON” Position and ON/OFF Switch in “OFF” Position 
Control 
Knob
T-Stat 
Sensor 
ON/OFF 
Switch