Lennox CHA16, Руководство по обслуживанию

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Page 35
10-Time Delay DL5
Time delay DL5 is only used in 50 and 75kW
208/230V electric heat units. The delay is identical
to DL2 and DL4. DL5 allows four stages of heat by
providing a timed interval between the third and
fourth heating elements.
11-Time Delay DL18
Time delay DL18 is only used in 75kW 208/230V
electric heat units. The delay is identical to DL2,
DL4 and DL5. DL18 allows five stages of heat by
providing a timed interval between the fourth and
fifth heating elements. DL18 is energized only after
time delay DL5 closes.
12-High Temperature Limit S15 (Primary)
S15 is the primary high temperature limit. It is located
in the electric heat unit immediately downstream
from the heating elements. S15 is a singlepole
singlethrow normally closed thermostat wired in se
ries with the first stage contactor coil. The thermostat
actuates at temperatures shown in table 12. The tem
perature differential is factory set and is not adjust
able.
S15 SPST AUTO-RESET HIGH TEMPERATURE LIMIT
Open on Rise Close On Fall
All
Unit
175 ° F + 5 ° F 135 ° F + 10 ° F
TABLE 12
7.5 Tons And Under
Voltage
145
°
F + 5
°
F 105
°
F + 6
°
F
10 Thru 12.5 Tons
208/230V
125
°
F + 5
°
F 95
°
F + 6
°
F
15 Tons And Larger
460 & 575V
All
145 ° F + 5 ° F* 105 ° F + 6 ° F *
130
°
F + 5
°
F 90
°
F + 6
°
F
*Early Production
When S15 opens, indicating a problem in the system,
contactor K15 is deenergized. When K15 is deener
gized, first stage and all subsequent stages of heat are
deenergized. Since the indoor blower is controlled by
demand (K9 remains energized), the indoor blower con
tinues operating.
13-High Temperature Limit S63 (Redundant)
S63 is a redundant (primary) temperature limit fac
tory installed in 460 & 575V units. The redundant
limit is operable only when connected to CHP16
units and does not function when connected to
CHA16 units.
14-High Temperature Limit S20 (Secondary)
Each heating element assembly is electrically connected
to two high temperature limits S20 (refer to wiring dia
grams in back of this manual). Each limit is connected in
series with one leg of the threephase element assembly.
The third leg of each assembly is not equipped with a lim
it. Threephase operating characteristics allow one of the
other two limits to protect the third leg.
Each S20 limit is physically located adjacent to the
element it is protecting. S20 is a singlepole single
throw normally closed thermostat. The thermostat ac
tuates at 185
°
F + 8
°
F on a temperature rise and can
not be reset. Once tripped, it must be replaced.
15-Fuse F3
F3 is a current limiting fuse connected in series with
each leg of electric heat (each stage of electric heat
uses three fuses). Fuses used in CHA16 series heat
ing sections are shown in table 13.
kW &
Voltage
TABLE 13
Fuse F3
1st Stage
Fuse F3
2nd Stage
Fuse F3
3rd Stage
Fuse F3
4th Stage
(3 Fuses) (3 Fuses) (3 Fuses) (3 Fuses)
---
---
--- ---
---
---
60 Amp
250V
--- ---
30 Amp
600V
--- ---
60 Amp
250V
60 Amp
250V
---
60 Amp
600V
--- --- ---
60 Amp
250V
60 Amp
250V
60 Amp
250V
---
60 Amp
600V
30 Amp
600V
60 Amp
250V
60 Amp
250V
60 Amp
250V
60 Amp
250V
60 Amp
600V
60 Amp
600V
---
208/230V
460 & 575V
208/230V
460 & 575V
208/230V
460 & 575V
208/230V
460 & 575V
CHA16 ELECTRIC HEAT SECTION FUSE RATINGS
--- --- ---
---
60 Amp
250V
--- ---
208/230V
---
60 Amp
250V
60 Amp
250V
---
60 Amp
600V
--- --- ---
208/230V
460 & 575V
60 Amp
600V
60 Amp
600V
30 Amp
600V
---
460 & 575V
10kW
10kW
15kW
15kW
20kW
20kW
30kW
30kW
45kW
45kW
60kW
60kW
75kW
60 Amp
600V
60 Amp
600V
60 Amp
600V
---
460 & 575V
90kW
--- ---
60 Amp
250V
60 Amp
250V
60 Amp
250V
---
60 Amp
600V
30 Amp
600V
208/230V
460 & 575V
40kW
40kW
60 Amp
600V
30 Amp
600V 460 & 575V
50kW
--- ---
60 Amp
600V
30 Amp
600V 460 & 575V
50kW
60 Amp
600V
30 Amp
600V
460 & 575V
30 Amp
600V
208/230V
75kW
60 Amp
250V
60 Amp
250V
Fuse F3
5th Stage
(3 Fuses)
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---
---
---
---
---
---
---
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60 Amp
250V
60 Amp
250V
60 Amp
250V
---
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