ADJUSTMENT AND SERVICE
NOTE:
Parallel Systems include Thermostatic
Water Mixing Valves, which must be regularly
maintained to provide best performance.
Frequency of cleaning depends on quality of local
water conditions and usage. See Maintenance
Guide and Record MGR-1001
Leonard Type TM Thermostatic Water Mixing
Valves are simple in design and may be easily
cleaned, adjusted and repaired. If the installation
is accessible, servicing may be completed without
disconnecting the valves.
WARNING
These mixing valves are equipped with an adjustable high temperature limit stop factory set at approximately
120°F (49°C) with an incoming hot water supply temperature of 150°F (65.5°C). If the hot water supply
temperature of the job is greater than 150°F (65.5°C), the valves when turned to full HOT will deliver water in
excess of 120°F (49°C) and the limit stop
MUST BE RESET BY THE INSTALLER!
TO RESET ADJUSTABLE HIGH TEMPERATURE LIMIT STOP:
TM-1520A SMALL MIXING VALVE
TM-1520A LARGE MIXING VALVE
1. Loosen LTR screw
2. Remove SNAP CAP, SCREW & WASHER, Remove
POINTER.
3. Temporarily place POINTER on the spline rod, turn RIGHT
for warmer temperature, turn LEFT for cooler temperature.
When valve is delivering warmest temperature desired, remove
the pointer.
4. Replace POINTER on the spline rod so that its RIGHT edge is
resting against the STOP SCREW located on the RIGHT SIDE
OF THE COVER.
5. The new maximum temperature has now been set. Test this
temperature by holding a thermometer under the flow of water
to be certain it is as desired.
POINTER
SET SCREW
SNAP
CAP
LTR
C
H
THERMOSTATIC
LEONARD
STOP
SCREW
1. Remove SNAP CAP, SCREW & WASHER & POINTER.
2. Loosen LTR screw, and remove retaining ring and stop.
3. Temporarily place POINTER on the spline rod, adjust to
desired temperature, and remove the pointer.
4. Push stop on rod so that its LEFT edge is resting against the
fine adjustment screw on cover.
5. Turn, fine adjustment screw if necessary, (clockwise for
slightly higher temperature, counter clockwise for slightly
lower temperature).
6. The new maximum temperature has now been set. Test this
temperature by holding a thermometer under the flow of water
to be certain it is as desired.
RETAINING RING
SCREW
ADJUSTMENT
FINE
H
L
WEB
D
T
O
C
STOP
LTR SET SCREW
IMPORTANT! ALL MIXING VALVES MUST BE SET AT THE SAME
OPERATING TEMPERATURE.
SEE PAGES: 9 & 11 FOR COMPLETE PARTS BREAKDOWN
Check for significant variations in outlet flow. Thermostatic valves will NOT provide the desired accuracy
outside of their flow capacity range. Minimum flows must be no less than shown (see Flow Capacities, page 12).
If installed on a recirculated hot water system, make certain the valve is piped according to Leonard’s Required
Piping Methods (see page 4).
REMEMBER! THIS IS A CONTROL DEVICE WHICH MUST BE CLEANED AND MAINTAINED
ON A REGULAR BASIS. (SEE MAINTENANCE GUIDE AND RECORD, MGR-1001).
3
