Burnham Apex APX399 Installation, Operating And Service Instructions page 104

Xi. Service and Maintenance
e. Using pliers, release spring clip securing the
overflow switch to condensate trap body and remove
the switch. Note that the switch has factory applied
silicon adhesive seal, which may have to be carefully
cut all around to facilitate the switch removal.
f. Using pliers, release spring clip securing condensate
trap body to the heat exchanger bottom drain stab.
g. Firstly, pull the trap downwards to release from
the heat exchanger bottom drain stab; secondly,
pull the trap end from left side jacket panel sealing
grommet and remove the trap from boiler.
h. To reinstall the trap, reverse above steps.
i. If the original condensate overflow switch is to
be re-used, follow the appropriate switch removal
steps from Condensate Overflow Switch Removal
and Replacement procedure above.
j. Insure that fresh silicon sealant is applied to
the overflow switch threads, and the switch is
properly oriented relative to the trap body -
the arrow molded into the switch hex side end
must face down for proper switch operation.
See Figure 59 "Condensate Overflow Switch
Orientation" for details. Insure that pressure
switch hose is reconnected to the trap.
Outdoor air Temperature Sensor
Temperature versus resistance
(P/n 102946-01)
(10kOhm nTC Sensor)
Outdoor Temperature
°F
-20
-10
0
10
20
30
40
50
60
70
76
78
80
90
100
110
120
104
(continued)
Ohms of
resistance
°C
-28.9 106926
-23.3 80485
-17.8 61246
-12.2 47092
-6.7 36519
-1.1 28558
4.4 22537
10.0 17926
15.6 14356
21.1 11578
24.4 10210
25.6 9795
26.7 9398
32.2 7672
37.8 6301
43.3 5203
48.9 4317
k. Restore power supply to boiler. Fill up the trap
(see Section V "Condensate Disposal") and
verify the switch operation.
Header Temperature Sensor
Temperature versus resistance
(P/n 101935-01 or 103104-01)
(10kOhm nTC Sensor), Beta of 3950
Temperature
°F °C
32 0
50 10
68 20
77 25
86 30
104 40
122 50
140 60
158 70
176 80
194 90
212 100
248 120
Supply, return and Stack Temperature Sensor
Temperature versus resistance
(12kOhm nTC Sensor), Beta of 3750
Temperature
°F °C
32 0
50 10
68 20
77 25
86 30
104 40
122 50
140 60
158 70
176 80
194 90
212 100
230 110
248 120
Ohms of
resistance
32648
19898
12492
10000
8057
5327
3602
2488
1752
1256
916
697
386
Ohms of
resistance
36100
22790
14770
12000
9810
6653
4610
3250
2340
1710
1270
950
730
560