Honeywell L, M, R7140G IGNITION SPARK RESPONSE TEST (ALL ULTRAVIOLET DETECTORS)

R7140G,L,M BURNER CONTROL MODULES

66-1153—03 32

If hot refractory saturation occurs, the condition must be

corrected. Add an orifice plate in front of the cell to restrict the

viewing area, lengthen the sight pipe or decrease the pipe

size (diameter). Continue adjustments until hot refractory

saturation is eliminated.

Hot Refractory Hold-in Test

(Rectifying Photocell, Infrared

Detectors, Ultraviolet Detectors)

This condition can delay response to flame failure and also

can prevent a system restart if hot refractory is detected.

Infrared (lead sulfide) detectors can respond to infrared rays

emitted by a hot refractory, even when the refractory has

visibly ceased to glow. Infrared radiation from a hot refractory

is steady, but radiation from a flame has a flickering

characteristic. The infrared detection system responds only to

flickering infrared radiation; it can reject a steady signal from

hot refractory. The refractory steady signal can be made to

fluctuate if it is reflected, bent or blocked by smoke or fuel mist

within the combustion chamber. Be careful when applying an

infrared system to verify its response to flame only.

The ultraviolet detector can respond to hot refractory above

2300°F (1371°C).

1. Operate the burner until the refractory reaches its

maximum temperature (Infrared Only). If the installation

has a multi-fuel burner, burn the heavier fuel that is most

likely to reflect, bend or obscure the hot refractory

steady infrared radiation.

2. When the maximum refractory temperature is reached,

close all manual fuel shutoff valves, or open the

electrical circuits of all automatic fuel valves.

3. Visually observe when the burner flame or FLAME LED

goes out. If this takes more than three seconds, the

infrared detector is sensing hot refractory.

4. Immediately terminate the firing cycle. Lower the

setpoint to the operating controller, or set the Fuel

Selector Switch to OFF. Do not open the master switch.

NOTE: Some burners continue to purge oil lines

between the valves and nozzles even though the

fuel valves are closed. Terminating the firing

cycle (instead of opening the master switch)

allows purging the combustion chamber. This

reduces a buildup of fuel vapors in the

combustion chamber caused by oil line purging.

5. If the detector is sensing hot refractory, correct the

condition by one or more of the following procedures:

a. Add an orifice plate in front of the cell to restrict the

viewing area of the detector.

b. Resight the detector at a cooler, more distant part of

the combustion chamber. Make sure the detector

properly sights the flame.

c. Try lengthening the sight pipe or decreasing the pipe

size (diameter).

For details, refer to the detector Instructions and the

equipment Operating Manual. Continue adjustments until hot

refractory hold-in is eliminated.

IGNITION SPARK RESPONSE TEST (ALL ULTRAVIOLET DETECTORS)

Test to make certain that the ignition spark is not actuating the

FLAME LED:

1. Close the pilot and main burner manual fuel shut-off

valve(s).

2. Start the burner and use the Run/Test Switch (if

available) to stop the sequence in the PILOT IGN

period. Ignition spark should occur, but the flame signal

should not be more than 0.5 Vdc.

If the flame signal is higher than 0.5 Vdc and the FLAME

LED does come on, consult the equipment operating

manual and resight the detector farther out from the

spark, or away from possible reflection. It may be neces-

sary to construct a barrier to block the ignition spark

from the detector view. Continue adjustments until the

flame signal due to ignition spark is less than 0.5 Vdc.

NOTE: The Honeywell Q624A and Q652B Solid State

Spark Generators prevent detection of ignition

spark when properly applied with C7027, C7035,

C7044 or C7061 Ultraviolet Flame Detectors. The

Q624A and Q652B are only for use with gas

pilots.

Response To Other Ultraviolet

Sources

Some sources of artificial light (such as incandescent or

fluorescent bulbs, mercury sodium vapor lamps and daylight)

produce small amounts of ultraviolet radiation. Under certain

conditions, an ultraviolet detector responds to these sources as

if it is sensing a flame. To check for proper detector operation,

check the Flame Failure Response Time (FFRT) and conduct

Safety Shutdown Tests under all operating conditions.

Flame Signal With Hot Combustion

Chamber (All Installations)

With all initial start-up tests and burner adjustments com-

pleted, operate the burner until the combustion chamber

is at the maximum expected temperature.

Observe the equipment manufacturer warm-up

instructions.

Recycle the burner under these hot conditions and

measure the flame signal. Check the pilot alone, the main

burner flame alone, and both together (unless monitoring

only the pilot flame when using an intermittent pilot, or

only the main burner flame when using DSI). Check the

signal at both High and Low Firing Rate positions and

while modulating, if applicable.

Check the FFRT of the flame amplifier and relay module.

Lower the setpoint of the operating controller and observe

the time it takes for the burner flame to go out. This

should be within the maximum FFRT.

If the flame signal is too low or unsteady, check the flame

detector temperature. Relocate the detector if the temper-

ature is too high.

If necessary, realign the sighting to obtain the proper sig-

nal and response time.