Number One
Airconditioning
I\Mer
Installation Instructions
Division of
Carrier Corporatio
e
Carrier Parkway • Syracuse NY 13221
Accessory Optimizer Control
Usage — Install the Optimizer Control (Fig. 1) with
Model 38CQ, HQ or RQ split system heat pump
that has been added to standard oil or gas furnace.
This Optimizer system provides cooling as required
and heating season operation that maximizes system
usage and benefits.
Optimizer usage is also beneficial in some heat
pump/electric furnace systems such as those with
Model 40ES. These Optimizer systems operate the
same as gas or oil furnace/heat pump systems.
CAUTION: If saowfaB is over 20 in.
(508 mm), the minimum setpoint of the Opti
mizer Control is 35 F (L6 C),
OPTIMIZER SYSTEM
INSTALLATION REQUIREMENTS
^Indoor Airflow Capacity of furnace fan and duct
system, as is, or with modification, must be approxi
mately 400 to 500 cfm per 12,000 Btuh (189 to 236 1/ s
per 3.5 kW) of heat pump cooling capacity (equiv
alent to 33 to 42 cfm per 1,000 Btuh [15.6 to 19.8 1/s
per .3 kW]). Determine existing system cfm capa
bility (without indoor coil installed) by standard
temperature rise or pressure drop methods. Calcu
late permissible cooling capacity.
Example:
System cfm capability = 1176 cfm (555 1/s)
Maximum heat pump cooling capacity permis
sible at 1176 cfm (555 1/s) with minimum require
ment of 400 cfm (189 1/s)/12,000 Btuh (3.5 kW):
1176
X 12,000 Btuh = 35,280 Btuh
400
55
X 3.5 kW = 10.2 kW
189
With indoor coil installed, a larger furnace motor
or blower assembly may be required. After installing
coil, recheck cfm, and modify blower assembly or
duct system as required.
RECOMMENDED INDOOR COIL LOCATION
is on supply air side of gas or oil furnace, supply or
return air side of Electric Furnace (40ES). See
Fig. 2 and Coi/ Installation Instructions.
SYSTEM INDOOR THERMOSTAT — Use
thermostat-subbase package 38CQ900-111 for
manual cooling/heating changeover; 38CQ900-081
for automatic cooling/heating changeover. Re
quired thermostat has manually operated emer
gency heat switch which locks out heat pump and
activates furnace.
SYSTEM TRANSFORMER (24-v) CAPACITY
required for most Optimizer systems is 60 va.
Replace gas or electric furnace transformer as re
quired with 60-va transformer. Carrier Part No.
HT01AW230.
If oil furnace has a 40-va (or less) transformer, and
accessory humidifier or air cleaner is wired in system,
add another transformer to system to acquire 60-va
total transformer capacity. Connect additional
transformer in parallel and in phase with existing
transformer as follows:
1. Connect 115-volt primary leads on 20-va trans
former to same points as primary leads on exist
ing transformer.
2. Attach one 24-volt secondary lead from 20-va
transformer to furnace terminal C or common
side of existing transformer.
3. Apply 115-volt power. Measure voltage between
unconnected 24-v lead, on 20-va transformer,
and terminal R on furnace. If voltage is zero,
connect 24-v lead to terminal R. (Transformers
are in phase.) If 50 volts (approximately) is
measured, reverse 115-v primary lead connection
on one transformer. Recheck voltage — if zero,
connect 24-v lead to terminal R.
FURNACE FAN RELAY is required. Add to fur
nace when not so equipped. Furnaces shown in
Control Circuit Connections, Fig. 3, have fan relay.
Carrier Corporation 1980
Form 38CQ-17SIM
OPTIMIZER COIMTROU^a^LLATIOISI
A 5-ft (1.5 m) capillary tube connects the outdoor
temperature sensing bulb to Optimizer body. Locate
bulb outdoors behind the shade shield. Mount
Optimizer indoors for easy accessibility, Fig. 2.
LINE-1 LINE-2
I
I r~
L2^LI
1
I I
________
I
_______
THERMOSTAT TERMINALS
38CQ900-Ill
(MAN CHANGEOVER)
38CQ900-08I
(AUTO CHANGEOVER)
]
I I
IA "SEC-2
OPTIMIZER SYSTEM-38 SERIES HEAT
PUMP/58SE OR 58GS GAS FURNACE;
COOLING, HEATING, EMERGENCY
HEAT
58H SERIES
OIL FURNACE
PRIMARY RELAY
TERMINALS
HEAT PUMP
TERMINAL BOARD
Fig. 2 — Typical Optimizer Installation
System Wiring Data (24 v)
1. Connect Optimizer system control wiring, Fig. 3.
2. Furnace transformer supplies 24-v power for
system.
3. Required indoor fan relay is energized thru ter
minal G, Fig. 3.
4. Electric furnace terminals R and C must be
powered by transformer 24-v secondary; if not,
change wiring.
5. For example of complete Optimizer system
diagram, refer to heat pump wiring book.
Optimizer Control Settings
^1. Set Optimizer temperature dial to transfer heat
ing function to furnace at a temperature equal
to the calculated balance point plus the control
differential setting (factory set at 10 F [-12.2 C]).
Balance point is usually 30 F (-1.1 C) to 35 F
(1.6 C). Calculation sheets are available from
Carrier. Minimum setting is 20 F (-6.7 C).
2. Factory differential setting is 10 F (-12.2 C).
In areas of less than 20 in. (508 mm) annual snow
fall, setting can be readjusted to 5 F (-15 C).
Remove Optimizer cover for access to differ
ential adjustment wheel.
SUPPLEMENTAL
TRANSFORMER
IF REQUIRED
OPTIMIZER SYSTEM-38 SERIES HEAT PUMP/58H OIL
FURNACE; COOLING. HEATING, EMERGENCY HEAT
CAUTION: The transformer's primary wires must be connected to the black
and white relay wires as shown, since going to LI and L2 would bypass//m/i
switches and make furnace operation unsafe
THERMOSTAT TERMINALS
38CQ900-III
(MAN. CHANGEOVER)
38CQ900-08I
(AUTO. CHANGEOVER)
OPTIMIZER SYSTEM-38 SERIES HEAT PUMP/40ES ELEC
TRIC FURNACE; COOLING, HEATING, EMERGENCY HEAT
Contacts 1 & 3 = Coil
Contacts 2 & 4 = Normally Open
Contacts 5 & 6 = Normally Closed
NOTES; 1 Place outdoor thermostat across W2 and W3 to limit first stage
2 Use Carrier part no HK61KK324 relay or any pilot duty lockout
LR — Lockout Relay
"Strip" heat Use jumper wire if outdoor thermostat (ODT) is
not used.
relay (24 v) double-pole, single-throw with one normally open
and one normally closed set of contacts
40 ES
ELECTRIC
FURNACE
TERMINALS
LEGEND
HEAT PUMP
TERMINAL BOARD
^ Fig. 3 — Control Circuit Connections
® Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab
5a 5a
Form 38CQ-17SIM Supersedes 38CQ-14SI
Printed in U S A
5-80
PC 101
Catalog No 533-839
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