System Operation; Defrost System - Ducane 13HPD-018-230 Instructions Manual

Table 3. Normal Operating Pressure − Liquid +10 and Vapor +5 PSIG*
Minor variations in these pressures may be expected due to differences in installations. Significant differences could mean
that the system is not properly charged or that a problem exists with some component in the system.
Model 13HPD−018
Temp. 5F (5C)**
Liquid / Vapor
65 (18) 141 / 81
75 (24) 163 / 82
85 (29) 191 / 84
95 (35) 222 / 85
105 (41) 256 / 87
115 (45) 296 / 89
50(10) 192 / 64
40 (4) 180 / 53
30 (−1) 172 / 43
20 (−7) 164 / 34
*These are most−popular−match−up pressures. Indoor match up, indoor air quality, and indoor load cause pressures to vary.
**Temperature of the air entering the outside coil.

System Operation

The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is in the ON position, the indoor blower operates
continuously.
LIQUID LINE BI−FLOW FILTER DRIER
The pre−installed liquid line bi−flow filter drier as illustrated
in figure 1 is approved for use with HCFC−22 only. Do not
replace liquid line filter drier with component designed for
use with HFC−410A.
EMERGENCY HEAT FUNCTION (ROOM
THERMOSTAT)
An emergency heat function is designed into some room
thermostats. When the room thermostat is placed in the
emergency heat position, the outdoor unit is disabled and
only the backup heat source is used to provide heat.
Typically the thermostat will have an LED or will indicate on
the display the system is in the emergency heat mode to
remind the homeowner that he is operating in the
emergency heat mode.
Emergency heat is usually used during an outdoor
shutdown, but it should also be used following a power
outage if power has been off for over an hour and the
outdoor temperature is below 50°F (10°C). System should
be left in the emergency heat mode at least six hours to
allow the crankcase heater sufficient time to prevent
compressor slugging.
IMPORTANT
13HPD−024 13HPD−030
Liquid / Vapor Liquid / Vapor
148 / 80 146 / 78
176 / 82 171 / 79
206 / 83 201 / 80
240 / 84 233 / 81
277 / 86 271 / 81
322 / 87 313 / 83
185 / 60 198 / 58
176 / 50 188 / 47
165 / 49 175 / 35
162 / 31 163 / 26
13HPD−036 13HPD−042
Liquid / Vapor Liquid / Vapor
Cooling
154 / 78 139 / 67
180 / 80 163 / 74
216 / 81 191 / 81
246 / 81 220 / 84
284 / 82 256 / 85
328 / 85 294 / 87
Heating
196 / 58 204 / 59
185 / 47 195 / 49
176 / 37 184 / 39
170 / 30 178 / 32
HIGH PRESSURE SWITCH (S4) (−018 MODEL ONLY)
S4 is standard on the 13HPD−018 model and an option on
all other models. S4 is a manual re−set switch located on
the liquid line. When liquid line pressure rises above the
factory setting of 410 + 10 psi, the switch opens and shuts
off the compressor.
MANUAL RESET
BUTTON
Figure 19. High Pressure Switch (S4) Manual Reset

Defrost System

The 13HPD defrost system includes two major
components, a defrost control (CMC1) and defrost
thermostat switch (S6).
Page 21
13HPD−048 13HPD−060
Liquid / Vapor Liquid / Vapor
146 / 75 145 / 72
171 / 77 171 / 75
198 / 78 199 / 77
229 / 79 230 / 78
268 / 81 266 / 79
308 / 81 304 / 81
197 / 39 212 / 57
189 / 31 200 / 47
181 / 25 187 / 38
175 / 18 174 / 34
13HPD SERIES