Defrost cycle timer, Demand defrost control, Optional outdoor thermostat – Reznor Q6SE Unit Installation Manual User Manual

Page 10: Optional electric heater kits, Mostat connections are listed in, Table 2

table 3. Demand Defrost curve Profiles

jUMPER

PoSItIon

MInIMUM tIME

BEtWEEn

DEFRoStS (MIn)

tERMInAtE

tEMPERAtURE

(° F)

30 SEconD

coMPRESSoR

DElAY FUnctIon

YES

table 2. thermostat Wire Gauge

thermostat

Wire Gauge

Recommended t-Stat Wire length

(Unit to t-Stat)

2-Wire

(Heating)

5-Wire

(Heating/cooling)

140

225

110

Refer to the thermostat's instruction sheet for detailed

mounting and installation information.

Defrost cycle timer

The defrost cycle timer controls the time interval of the hot

gas defrost after the defrost sensor closes. It is located

in the lower left corner of the defrost control board on the

low voltage side of the control box. Three interval settings

are available: 30 minutes, 60 minutes, and 90 minutes.

Time setting selection is dependent on the climate where

the unit is being installed.
• Example 1: Dry climate of Southern Arizona - A 90

minute setting is recommended.

• Example 2: Moist climate of Seattle, Washington - A 30

minute setting is recommended.

To set the cycle timer, place the timing pin on the defrost

control board to the desired time interval post.

notE: All

units are shipped from the factory with the default time

setting of 30 minutes.

Demand Defrost control

The demand defrost board controls the defrost cycle

in response to ambient temperature, outdoor coil

temperature and accumulated compressor run time. The

heat pump is allowed to operate in the heating mode

until the combination of outdoor ambient and outdoor

coil temperatures indicate that defrosting is necessary,

based on the programmed defrost curve. There are four

preprogrammed defrost curves on the board.

• A jumper pin is used to switch between the different

curves. The default jumper position is curve 1 and is the

recommended setting for most standard applications.

See

Table 3

for additional defrost curves settings.

• The factory default setting does not include a 30 second

compressor delay function and has a 40° F defrost

terminate temperature. If additional defrost time is

needed, a higher terminate temperature is available

by selecting a different demand curve.

notE: The 30

second compressor delay function is optional and based

on the demand curve selected.

• The standard defrost cycle will terminate after 13 minutes

and 39 seconds or when the coil temperature reaches

its terminate temperature, whichever occurs first.

• The defrost board is equipped with a 5 minute Anti-Short

Cycle Delay (ASCD). The compressor will not turn on

until it reaches the minimum 5 minute off time.

• The control contains a forced - defrost feature, which

places the system into defrost mode every 6 hours and

4 minutes, unless the coil temperature is above the

selected terminate temperature.

• The system can be manually forced into defrost mode at

any time by shorting the

tESt terminals on the demand

defrost board together for more than 9 seconds. The

coil temperature sensor does not need to be cold when

the unit is forced into defrost. After the

tESt input is

removed, the defrost mode will terminate in 13.7 minutes,

if the coil temperature is above the terminate set-point,

or when the

Y input is removed, whichever occurs first.

notE: If a demand curve is selected which has a 30

second compressor time delay in defrost, the delay is

reduced to 10 seconds in TEST mode.

optional outdoor thermostat

An outdoor thermostat can be installed in the field with

2-stage electric heat by removing the orange wire from

the

E terminal on the terminal block and connecting to the

outdoor thermostat. Connect the other side of the outdoor

thermostat to

W2 from the thermostat.

optional Electric Heater Kits

Optional electric heater kits are available in 5 kw through

20 kw heating capacities. Single package heat pumps

are designed to allow optional electric heat to be field

installed as required by the building’s particular heating

load. The options available for each unit are shown in the

heater kit installation instructions. A heating/cooling 24V

thermostat should be used when an electric heater kit is

installed.

notE: A 2-stage heating thermostat is required

if installing a 2-stage heater kit. As previously noted, a

field installed circuit breaker kit is available as a means

of electrical disconnect for the unit. Install the heater kits

as directed by the instructions supplied with the heater

kit. Follow all cautions and warnings as directed.