NTI INSTALLATION MANUALS

Part 16 - Shutdown

Supply/Return Temperature Sensors Tank Sensor DHW Outlet Sensor

A. Shutdown Procedure If the burner is not operating, disconnect the electrical supply. If the burner is operating, lower the set point value to 86 o F(for high temperature system) or 68°F (for low temperature system) and wait for the burner to shut o . Continue to wait for the combustion blower to stop, so all latent combustion gases are purged from the system. This should take a maximum of 40 to 90 seconds. Should the burner fail to light, the control will perform four more ignition trials prior to entering a lockout state. Note that each subsequent ignition trial will not occur immediately. After a failed ignition trial, the blower must run for approximately 5 seconds to purge the system. If the burner lights during any one of these ve ignition trails, normal operation will resume. If the burner does not light after the fth ignition trial, the control will enter a lockout state. This lockout state indicates that a problem exists with the boiler, the controls, or the gas supply. Under such circumstances, a quali ed service technician should be contacted immediately to properly service the boiler and correct the problem. If a technician is not available, press a button on the display to wake it. Then press the RESET button to remove the lockout state so additional trials for ignition can be performed. If the RESET key is not pressed (error code 501 or 503), the boiler will reset automatically after an hour. B. Failure to Operate

Outdoor Sensor

Outside Temperature ( o F)

Resistance (ohms)

Water Temp. ( o F)

Resistance (Ohms)

-22

178605

32

27219

-13

132045

41

22021

-4

98438

50

17926

5

73995

59

14674

14

56079

68

12081

23

42846

77

10000

32

32997

86

8315

41

25609

95

6948

50

20027

104

5834

59

15777

113

4917

68

12517

122

4161

77

10000

131

3535

86

8042

140

3014

95

6510

149

2586

104

5302

158

2228

113

4343

167

1925

176

1669

185

1452

C. Important

194

1268

202

1110

NOTICE

212

974

Table 37 - Sensor Temperature Resistance

It is extremely important that whenever work is performed on the plumbing system that either: • The appliance is powered o , and, • The area that is being worked on is valved o and isolated. Failure to take these measures could result in a dry- ring condition, explosion or re, substantial property damage, severe personal injury, or death.

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