Rheem RGPE series Installation Instructions Manual page 26

FIGURE 21
WIRING FOR OPTIONAL DEHUMIDIFICATION OPERATION AND HUMIDIFICATION WITH
OPTIONAL HUMIDIFIER (HUMIDIFIER WITH INTERNAL POWER SUPPLY) (FOR USE WITH
NON-COMMUNICATING THERMOSTATS)
FIGURE 22
HUMIDISTAT USED TO CONTROL DEHUMIDIFICATION IN COOLING ONLY (NO HUMIDIFIER)
(FOR USE WITH NON-COMMUNICATING THERMOSTATS)
airflow will be permanently reduced by
approximately 15% giving less than
optimal performance and possibly caus-
ing problems. It is not recommended to
leave this switch in the "ON" position
without a humidistat installed.
Control of dehumidification in cooling
and/or humidification in heating can be
done with a variety of methods depend-
ing on whether there is a communicat-
ing thermostat or a humidistat available
and depending on the type of operation
desired.
With systems configured with communi-
cating thermostats and condensers,
dehumidification is controlled by the
condenser and is not affected by the
position of dipswitch SW2-1 or the volt-
age (or lack of voltage) at the thermo-
stat terminal labeled "HUM STAT".
To determine which wiring diagram and
method to use, select from the following
configurations:
26
A. HUMIDIFICATION CONTROL ONLY
WITH NO DEHUMIDIFICATION
(REQUIRES OPTIONAL HUMIDIFI-
ER).
A1. WITH COMMUNICATING
THERMOSTAT
Humidifier control is included
with the (-)HC-TST412MDMS
(modulating, non-communicat-
ing) and (-)HC-TST550CMMS
(full-color communicating)
model thermostats. However, it
is not included with the (-)HC-
TST501CMMS model commu-
nicating thermostat. The latter
thermostat should not be used
if humidification control is
required. To wire the furnace
for humidification control using
the former thermostat, refer to
the wiring diagram in Figure
19(I). Be sure not to install the
jumper between "R" and "HUM
STAT" on the furnace con-
trol. Installing this jumper
will operate the humidifier
any time there is a heat call.
Without the jumper, the
humidification call from the
thermostat must be active
and a heat call must be pre-
sent with the blower running.
A2. WITH NON-COMMUNICAT-
ING THERMOSTAT
A2-1 CONTINOUS HUMID-
IFIER OPERATION
DURING HEATING.
For continuous humid-
ifier operation during
heating, refer to
Figure 19 (I) and
make sure to install
the jumper between
the thermostat termi-
nals labeled "R" and
"HUM STAT". A sepa-
rate humidistat is not
required for this con-
figuration and the
humidifier will turn on
whenever there is a
call for heat and the
blower is running.
A2-2 CONTROLED
HUMIDIFIER OPERA-
TION USING A
HUMIDISTAT
(REQUIRES OPTION-
AL HUMIDISTAT).
Controlled humidifica-
tion can be accom-
plished using a
humidistat as shown
in Figures 20 (II) or 21
(III). These figures
show installation of a
humidifier with exter-
nal and internal power
supplies respectively.
Dehumidification oper-
ation will be disabled if
the dipswitch SW2-1
is in the "OFF" posi-
tion. If this switch is in
the "ON" position,
dehumidification con-
trol will be active.
B. DEHUMIDIFICATION CONTROL
WITH NO HUMIDIFICATION
B1. For communicating ther-
mostats listed with this fur-
nace, dehumidification is
controlled automatically
when selected at the ther-
mostat and additional wiring
is not necessary. The actual
airflow demand (reduced for
dehumidification) is request-
ed of the furnace by the
condenser.