Powers 420U Series Under-the-Counter Thermostatic Tempering Valves User Manual
Page 6
NOTE: When replacing hot water seat, do not
over tighten!
Figure 6.
The hot water seat can be removed with a
7
⁄
8
”
(22mm) socket wrench. (Max. 40 in–lbs. torque.)
NOTE: After completing any maintenance/repairs,
check maximum discharge temperature 115°
(46°C). Reset if necessary.
Pull out the combination seat with a pair of pliers,
pulling on the two opposing lugs. One plier can be
used by alternately pulling on the two opposite
lugs until the seat can be removed by hand. Pull
out the valve assembly and return spring as
shown in Figure 5.
Figure 5.
Figure 4.
Figure 7.
1. Remove the thermostatic motor. Make the follow-
ing test to determine whether the thermostatic
motor is in operating condition.
2. Thermostatic motor bellows should offer firm, not
spongy resistance to a rigid blunt object inserted
inside the bellows. If it does not offer firm resist-
ance, the thermostatic motor is not fully charged
and should be replaced.
3. Place the thermostatic motor sleeve in the motor
as shown in Figure 7. Immerse the thermostatic
motor into 75°F (24°C) water for a few minutes.
The thermostatic motor should cause an approxi-
mate 1/32
″
(0.8mm) travel with the 25° (13°C) tem-
perature difference. In other words, the top of the
sleeve should be approximately 1/32
″
(0.8mm)
higher at 100°F (38°C) than it was at 75°F (24°C). If
this distance is much less, the thermostatic motor
has lost part of its charge and should be replaced.
THERMOSTATIC MOTOR TESTING
A new thermostatic motor can be substituted. Use pli-
ers to separate motor from stem. Locate the pliers
near washer. To avoid damage, be certain not to
squeeze thermostatic motor too firmly. (See figure 4.)
Remove four bonnet screws and pull out bonnet
assembly. The motor and motor sleeve should come
out with the bonnet. If not, they can be easily pulled
out. When reassembling, the open end portion of the
motor sleeve should be projecting out of the motor.
SERVICING
(Before assembling valve, make certain both water supplies to the valve are shut off.)
Depth distance
should be 1/32
″
Bonnet
Screws
Figure 3.
6