Checking Mixing Valve
1. Check swing of handle. Move handle to maximum HOT
position counterclockwise. Short end should be pointed
to HOT. If not, pull handle off and re-set.
2. CHECKING COLD WATER SHUT-OFF. Shut off
hot supply keeping cold supply open. Now move
mixing valve handle 1/4 turn counterclockwise. A
full volume of cold water should pass through valve.
Now move mixing valve handle as far as it will go
counterclockwise. The volume of cold water should be
reduced to a very small flow.
Failure of this to occur would indicate:
a. Piston #12 is stuck in one position. Unit has to be
cleaned.
b. Valve spring #15 has lost its strength and must be
replaced.
c. Cold water is in excess of 80°F.
3. CHECKING HOT WATER SHUT-OFF. Open both the
hot and cold supplies to mixing valve. Place handle at
hottest position (turned all the way counterclockwise).
Water should flow through valve at 115°F. If not,
adjust valve as explained under “TEMPERATURE
ADJUSTMENT.”
Now shut off the cold water supply to the mixing valve.
A properly operating mixer will shut off the hot water
almost instantly with hot water temperature supplying
the mixing valve at least 15 degrees higher than
maximum setting.
Failure to do so would indicate:
a. Dirt between the hot seat in liner and piston
prevents it from closing. Unit has to be cleaned.
b. The piston could be stuck so that it cannot move
because of scale or some other deposit in water.
Unit has to be cleaned.
c. The thermostat has lost its power and has to be
replaced with a new one.
d. On 3/4” valve only if hot pressure is over 50.p.s.i.,
valve may have a slight drip.
4. If a mixing valve will not shut off completely when
handle is turned all the way clockwise check:
a. Cold seat #9, may be worn or dirty - clean or
replace.
b. Seat of liner #16 could be eroded or cut - replace
piston & liner.
If the handle is hard to turn, remove spindle #4 and polish
with steel wool and lubricate with water insoluble grease or
Vaseline. Check O-Ring for imbedded foreign matter.
Inspection and Cleaning Valve
Shut off hot and cold water supply to mixing valve. Set
mixing valve handle on maximum hot position. Remove
body screws #22. Turn mixing valve handle toward cold
position until it forces cover off valve body. The thermostat
can now be examined.
Mixing valve
Valve is carefully assembled and tested at the factory
and set to deliver water at any temperature between full
cold and 115°F. Failure of the cold water supply will cause
the hot water seat to close. The label on the valve cover
is marked “HOT - COLD,” so that the handle can be set
accordingly.
When unit is not being used turn the handle toward COLD
position fully to shut off all flow.
Stop and Check Valves
At each inlet of the mixing valve is a screwdriver operated
union angle stop and check valve with built-in removable
sediment strainer. Both the cold and hot water angle stop
and check valves must be open at all times for proper
functioning of the valve.
The stop and check valves serve three purposes:
1. Their built-in removable strainers prevent dirt from
entering mixing valve.
2. They prevent the hot or cold water from by-passing
through the mixing valve.
3. They provide convenient means to shut the supplies to
the mixer for cleaning or repairs.
Stop and checks are required whenever downstream shut
off devices are used.
Temperature Adjustment
The temperature of the hot water supplying the mixing
valve should be at least 15 degrees higher than maximum
required valve setting. Valves are normally set at factory
for 115°F maximum outlet temperature with 140°F inlet. If
readjustment is required, proceed as follows:
1. Remove handle screw.
2. With narrow blade screwdriver, turn adjusting screw
#3 clockwise to reduce maximum outlet temperature
and counterclockwise to increase maximum outlet
temperature. This must be done with valve handle in the
hot position, turned counter-clockwise. Screw should
not be turned more than 1/2 turn at a time without
testing water temperature.
3. When temperature is correct, replace handle screw.
Adjusting screw #3 may not be turned counter-clockwise
more than 1-1/2 turns.
CAUTION: It is not recommended to set maximum
outlet temperature above the applicable plumbing code.
Piping Instructions
Before installing the mixer, blow out all pipe lines to be sure
that no dirt, such as pipe chips, wicking or lead, can enter
the mixing valve. Valve inlets are marked hot and cold.
Piping must go to proper inlets.
Maintenance
The Lawler thermostatic mixer should be checked
periodically for proper operation and cleaning. See
“INSPECTION AND CLEANING VALVE.” To test mixing
valve for proper setting and operation—proceed as follows:
