Powers 420U Series Under-the-Counter Thermostatic Tempering Valves User Manual

Page 3

OPERATION (continued from p. 1)

If the temperature of the mixture is higher than the
temperature setting, the thermostatic motor actuates
the valve assembly toward the hot water seat. Hot
water flow decreases and cold water flow increases.
Thus the mixture temperature is brought down to the
desired temperature. The reverse occurs when the
mixture temperature is lower than the temperature
setting.

A change in water temperature or pressure of either
hot or cold water supply will cause the thermostatic
motor to reposition the valve assembly to maintain
the desired delivery temperature.

420 Hydroguard supplies tempered water to
self-closing and/or solenoid valves, Powers rec-
ommends use of a shock absorber (Powers Part
No. 460-353) on the discharge line. This protects
the 420 Hydroguard thermostatic motor from
damage.

3. Locate the valve as close as possible to outlet

fixture to avoid waste of energy and water
except in applications where the valve is used as
a primary mixing valve to supply an entire build-
ing.

4. Correct valve sizing affects valve and system

performance; under- or over-sizing of the mixing
valve(s) can cause poor operation and possibly
injury. Refer to Sizing Information on page 6.

Adherence to these guidelines and recommenda-
tions promotes safe product use and ensures prop-
er valve performance.

1. Thermostatic water mixing valves are control

devices which must be cleaned and maintained
on a regular basis. Powers specifies periodic
maintenance at least once a year or immediate-
ly after any changes are made to the plumbing
system. Although annual cleaning is recom-
mended, frequency of cleaning depends on
quality of local water conditions. Refer to
Preventive Maintenance on page 4 for recom-
mended cleaning procedure.

2. Quick closing valves may cause damage to the

mixing valve by creating shock waves. When the

SAFETY & PERFORMANCE GUIDELINES

Note: All Powers products are subject to the Terms &
Conditions of Sale and Warranty Information, found in the
current Powers CPL Price List.