Page 36
TABLE 11 
Input Rate Seconds Natuarl Seconds LP/Propane
  138
 34 86
 24 60
6-Heat Exchanger
To Access or Remove Heat Exchanger From Unit:
1 -  
2 -   Remove access panel(s) and unit center mullion.
3 -   Remove gas valve, manifold assembly and burners.
4 -   Remove combustion air inducer. Pay careful 
    
are removed.
  Support heat exchanger (to prevent it from falling 
6 -   Remove screws supporting heat exchanger.
7 -   To install heat exchanger, reverse procedure. Be 
sure to secure all wires and check plumbing and 
burner plate for airtight seal. Screws must be 
7-Flame Sensing
Flame current is an electrical current which passes from 
the ignition control through the sensor electrode during unit 
operation. The current passes from the sensor through the 
-
trode) to complete a safety circuit. The electrodes should 
be located so the tips are at least 1/2” (12.7 mm) inside 
NOTE-Electrodes are not eld adjustable. Any alterations 
to the electrode may create a hazardous condition that 
can cause property or personal injury.
1 -  Disconnect power to unit.
2 -   Remove lead from sensing electrode and install 
       
sensing electrode and the sensing lead.
3 -   Reconnect power and adjust thermostat for heating 
demand.
4 -       
     Drop out signal is .09 or less.
  Disconnect power to unit before disconnecting 
meter. Make sure sensor wire is securely 
reconnected before reconnecting power to unit.
NOTE-If  the  meter  scale  reads  0,  the  leads  are 
reversed.  Disconnect  power  and  reconnect  leads 
for proper polarity.
B-Cooling System Service Checks
LGM units are factory charged and require no further ad-
however, charge should be checked periodically using the 
approach method. The approach method compares actual 
liquid temperature with the outdoor ambient temperature. 
See section IV- CHARGING.
NOTE-When unit is properly charged discharge line pres-
sures should approximate those in tables 6 through 9.
VI-MAINTENANCE
 WARNING
Electric shock hazard. Can cause injury or 
death. Before attempting to perform any 
service or maintenance, turn the electrical 
power to unit OFF at disconnect switch(es). 
Unit may have multiple power supplies.
 IMPORTANT
Label all wires prior to disconnection when servicing 
controls. Wiring errors can cause improper and 
dangerous operation. Verify proper operation after 
servicing.
A-Filters
  
        
Refer to local codes or appropriate jurisdiction for ap-
NOTE-Filters  must  be  U.L.C.  certied  or  equivalent  for 
use in Canada.
B-Lubrication
All motors are lubricated at the factory. No further lubrica-
tion is required.
PULL TO
REMOVE
FILTERS
FIGURE 26