W7100G DISCHARGE WATER TEMPERATURE CONTROL
63-4046—1 8
Table 3. Reset Modification Resistor Selection Chart
NOTE: Resistors shown are standard values for 1/8W, 1%,
metal film resistors.
SETTINGS AND ADJUSTMENTS
Setpoint Knob
HVAC Applications
Typical setpoints for HVAC applications range from 50 to 55°F
(10 to 13°C). These setpoints can change due to many
factors, including desired space temperature, required/desired
humidity conditions, etc.
Industrial Process Applications
Consult process unit manufacturer for recommended settings.
Reset Knob
HVAC Applications
Reset recommended for 5 to 10°F (3 to 6°C), depending on
desired maximum space temperature and space humidity
requirements. Higher discharge water temperature can result
in higher space temperature and humidity depending on
outside air temperature and humidity, or internal latent and
sensible heat load.
Industrial Process Applications
Reset is not recommended for these applications. However,
check with process manufacturer for other recommendations.
Control Band Knob
Set for desired control band. Increasing the control band
slows down the W7100 response, and increases the
temperature deviation. Lowering the control band speeds up
the W7100 response, while decreasing the temperature
deviation from setpoint.
The control band setpoint should be as narrow as possible
without causing hunting or rapid cycling. If instability, hunting,
or rapid cycling occurs, widen the control band setpoint.
Fast Response Input
The W7100G has the capability of changing the timings
between stages, the stage minimum ON timings and the stage
minimum OFF timings.To do this, you must select which
timing is desired (either 30 or 60 seconds):
— If you desire a 30 second delay, jumper terminals 9 and 10.
— If you desire a 60 second delay, leave terminals 9 and 10
open (unjumpered).
Number Of Stages
Select the proper resistor (see Table 2) that represents the
total number of controlled stages. Place this resistor across
terminals 7and 8 on the W7100G.
T-High (no
reset)
T-Low (full reset)
75 70 65 60 55 50
100 Rp 14.7K 7.68K 5.36K 4.22K 3.48K 3.01K
Rs 196 324 432 511 576 634
95 Rp — 14.7K 7.68K 5.36K 4.22K 3.57K
Rs — 187 316 412 499 562
90 Rp — 0 14.7K 7.68K 5.49K 4.22K
Rs — 0 178 309 412 499
85 Rp — — — 14.7K 7.87K 5.49K
Rs — — — 169 301 402
80 Rp — — — — 15.0K 7.87K
Rs————158294
75 Rp — — — — — 15.0K
Rs—————147
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