Table 18. (IG) Ignition System.

 

 

Wire Color

Voltage

Resistance

Connector

Pin

No.

Nos.

 

 

 

Grey-Grey

90-110 VAC

n/a

D1

1-2

 

Table 19. (FM) Combustion Fan Motor.

 

 

Wire Color

Voltage

Resistance

Connector

Pin

No.

Nos.

 

 

 

Red-Black

6-45 VDC

n/a

L1

1-2

White-Black

5-10 VDC

9.2-9.4k ohms

L1

2-4

Yellow-Black

11-13 VDC

3.5-3.9k ohms

L1

2-3

Set your meter to the hertz scale. Reading across the white and black wires at terminals 2 and 4 you should read between 60 and 420 hertz.

 

Table 20. Thermal Fuse / Overheat Switch.

 

 

Wire Color

Voltage

Resistance

 

Connector

Pin

 

No.

Nos.

 

 

 

 

Red-White

11-13 VDC

Below 1 ohms

 

B1

B13-

 

E1

E9

 

 

 

 

 

 

 

 

 

 

Flame Rod:

Place one lead of your meter to the flame rod and the other to ground. With the unit running, you should read between 5-150 VAC. Set your meter to micro-amp scale and series your meter in line with the flame rod. You should read 1 micro-amp or greater for proper flame circuit. In the event of low flame circuit, remove the flame rod and check for carbon or damage.

Heat Exchanger and Outgoing Water Temperature Thermistors:

Check all Thermistors by inserting meter leads into each end of the thermistor plug. Set your meter to the 20k scale and read resistance. Applying heat to the thermistor bulb should decrease the resistance. Applying ice to the thermistor bulb should increase the resistance. See below for examples of typical temperatures and resistance readings.

Example:

 

59ºF = 11.4-14kΩ

140ºF = 2.2-2.7kΩ

 

 

 

86ºF = 6.4-7.8kΩ

221ºF = 0.6-0.8kΩ

 

 

 

113º = 3.6-4.5kΩ

 

 

 

 

 

Table 21. Outgoing Water Thermistor.

 

 

Wire Color

 

Voltage

 

Resistance

Connector

Pin

 

 

No.

Nos.

 

 

 

 

 

White-White

 

n/a

 

See example

E4

E3-E4

 

 

above

 

 

 

 

 

 

Blue-Blue

 

n/a

 

See example

E3

E6-E5

 

 

above

 

 

 

 

 

 

 

Table 22. Heat Exchanger Temperature Thermistor.

 

Wire Color

 

Voltage

 

Resistance

Connector

Pin

 

 

No.

Nos.

 

 

 

 

 

Pink-Pink

 

n/a

 

See example

E2

5-10

 

 

above

 

 

 

 

 

 

 

 

Table 23. Surge Protector.

 

 

Wire Color

 

Voltage

 

Resistance

Connector

Pin

 

 

No.

Nos.

 

 

 

 

 

Black-White

 

108-132 VAC

 

n/a

C2

1-3

White-White

 

108-132 VAC

 

n/a

C1

1-3

54

Page 54
Image 54
Bradford-White Corp TGHE-160I-N(X), TGHE-1991-N(X) Flame Rod, Heat Exchanger and Outgoing Water Temperature Thermistors