Owner`s manual

Hydro-Hot Hydronic Heating System Shop Manual 07/03

Page 47

Section 8: Diesel-Burner Service, Maintenance, and Repair Information

Flame

Sensor

8.4 Flame Sensor

Function: The Flame Sensor is a photoresistive device which supplies

the Diesel-Burner's Control Unit with a DC voltage signal when it detects

a flame (i.e. light source).

NOTES:

A: In order to perform the following procedures it is necessary to

detach and reattach the Diesel-Burner Head. Be sure to review

Section 8.2, Page 42 for detaching and reattaching instructions.

B: Be sure to calibrate your ohmmeter prior to checking the Flame

Sensor for proper resistance values.

Component Test: Locate and detach the Flame Sensor's Green and Blue

wires from the C-Plug Harness wires, reference Figure 15. Connect the

Flame Sensor's Green and Blue wires to an ohmmeter, reference Figure

15. Check resistance by placing a shop rag over the Flame Sensor's glass

surface, to simulate a no flame condition, and then remove the rag (and

expose to a light source) to simulate a flame condition. If the Flame

Sensor is operating properly, the ohmmeter should register high resistance

(i.e. 100K when the glass surface is covered, and less than 300 

when exposed to a light source. If these resistance numbers cannot be

tained, the Flame Sensor must be replaced, reference the Flame

Sensor's "Replacement Procedure" below. Reference Section 10 for spare

parts information.

Cleaning Tips / Maintenance: For light dirt, dust, and/or carbon deposits,

simply wipe off the Flame Sensor with a soft cloth. Should heavy carbon

deposits be present, completely remove the Flame Sensor from the Photo

Disc and clean with brake cleaner, reference Figure 15.

Adjustment Procedure: N/A

Replacement Procedure:

1. Remove the Screw that fastens the Flame Sensor to the Photo Disc

and detach the sensor's Green and Blue wires from the C-Plug

Harness' Green and Violet wires, reference Figure 15.

2. Slide the tab of the new Flame Sensor into the provided slot in the

Photo Disc and secure in place with the screw, reference Figure 15.

Connect the Flame Sensor's Green wire to the Green C-Plug

Harness wire and the Blue wire to the C-Plug Harness' Violet

wire, reference Figure 15.