Maintenance - Mendota DXV-42 Installation & Operating Instructions Manual

1. ANNUAL MAINTENANCE OF MENDOTA UNITS IS REQUIRED. The following procedures must be
performed each year by a Mendota approved service person. NOTE: Any adjustments to burner, pilot or logs
must be done by a qualified Mendota service person.
A. Clean all lint and dust built-up around the control. Inspect
the condition of any wiring under the burner for melting or
damage.
B. Remove logs & coals and clean away any foreign matter
(lint, carbon, etc.) on the burner and logs. Be sure the burner
ports are "open". Clean the pilot and under side of the logs
for any carbon deposits. NOTE: Logs should be visually
checked for carbon "build-up". If carbon deposits are visible
on logs, unit should be turned off and Mendota service
person contacted. Be sure logs are re-installed per
instructions on pg. 20-24.
C. Make sure hot air outlet grills are free from lint and other
obstructions. Never block or obstruct grill openings. Check condition of gaskets, gaskets must be tight, re-
place if necessary.
D. Check that chimney flue and outlet are open and free of blockage.
E. Before re-installing glass, have qualified service person check the operation of the pilot with millivolt meter
and cycle the burner per LIGHTING INSTRUCTIONS (see pg. 25). Pilot must read a minimum of 460 mil-
livolts. Be sure all items in LIGHTING and INSTALLATION "check off " lists are completed (see pg. 25).
2. COMBUSTION SYSTEM MILLIVOLT READING:
Millivolt readings must be taken by a qualified installer at the time of installation and after any interruption in
burner operation. These readings will establish proper thermopile millivolt generation and assure trouble-free
burner operation. Readings must be taken with:
ing.
A. PILOT ONLY OPERATING - Thermostat "OFF" - Minimum Millivolts 460
Using a Millivolt Meter, a millivolt reading should be taken by attaching Meter leads to terminals #1 and #2
on the main gas valve. The Meter must read a minimum of 460 millivolts with the Pilot Light operating,
Thermo-stat turned "OFF" and Main Burner "OFF". To increase or decrease millivolts, (and pilot flame) ad-
just pilot screw on control (see
B. MAIN BURNER OPERATING - Thermostat "ON" - Minimum Millivolts 155
Using a Millivolt Meter a millivolt reading should be taken by attaching Meter leads to terminals #2 and #3
on the millivolt panel on the main gas valve. The Meter must read a minimum of 155 millivolts with the Gas
Cock Dial turned "ON", Thermostat "ON" and Main Burner operating. To increase or decrease millivolts
(and pilot flame) adjust pilot screw on control (see
CHECK TO TEST CONNECT
TEST METER
LEADS TO
TERMINA
LS
COMPLETE
A 2 & 3
SYSTEM
THERMO-
B 1 & 2
PILE
OUTPUT
VALVE
C 1 & 2
SYSTEM
RESISTANCE
THERMOSTAT
D 1 & 3
SYSTEM
RESISTANCE

MAINTENANCE

).
Figure 8
THERMOSTAT METER
CONTACTS READING
SHOULD BE
CLOSED 155 MV OR
MORE
OPEN GREATER
THAN
460 MV
CLOSED LESS THAN
3 OHMS
CLOSED LESS THAN
1.7 OHMS
a.) Pilot ONLY operating.
Figure 8: Millivolt Readings
Figure 8: Millivolt Readings
3
0
b.) Main Burner operat-
).