Q179A,B GAS PILOT BURNER ASSEMBLIES
Use high tension wire, of a type found acceptable by a
nationally recognized testing agency, for the wiring to the
ignition electrode (Q179A). High tension wires should be rated
electrically equivalent to type GTO-10 and should have
temperature and humidity characteristics adequate for the
application. If the ignition lead is exposed to temperatures
above 125°F (52°C), use Honeywell R1061012 Ignition Cable
rated at 350°F (177°C) or equivalent. For ignition installations
in a contaminated environment, use Honeywell R1239001
High Tension Cable rated at 220°F (104°C) or equivalent.
available, a dc ammeter with a 0 to 25 microampere scale can
be wired in series with the F lead of the flame detector circuit.
A minimum flame current of 2.0 microamperes is considered
acceptable.
The Honeywell BCS 7700 and 7800 SERIES Flame Safeguard
Control flame signals are measured in dc volts. A 20,000 volt/
ohm meter with a 0 to 5 or 10 Vdc scale is recommended for
measuring the flame signal of BCS 7700 controls while a one
megohm/volt meter is recommended for 7800 SERIES
controls. The flame signal voltages are measured as illustrated
in Fig. 5 and 6.
For wiring between the F terminal of the relay and the flame
electrode, use wire with moisture-resistant insulation. Number
14 single-conductor TW wire is adequate; however, those
portions of the leadwire exposed to temperatures over 125°F
(52°C) should also be heat resistant. For both heat and
moisture-resistant applications, use part no. R1298020 Flame
Rod Leadwire rated at 400°F (204°C) continuous duty or
equivalent.
The minimum acceptable flame signal voltage for the BCS
7700 controls is 2.2 Vdc (maximum expected is 4.98 Vdc).
The minimum acceptable flame signal voltage for the 7800
SERIES controls is 1.25 Vdc (maximum expected is 5.0 Vdc).
If the flame signal is less than the minimum acceptable for the
Honeywell Flame Safeguard Control used, adjust the flame
electrode (rod) to increase the flame signal to at least the
minimum acceptable level by loosening the clamp screw and
turning the electrode (rod) slightly to the right or left as
required. After the flame electrode (rod) is adjusted, check the
gap between the ignition electrode and burner tip (Q179A).
The gap must be between 1/16 and 3/32 inch.
Run a ground wire from the pilot burner to the relay to assure a
continuous, unchanging ground.
For detailed wiring diagrams, see the Instructions packed with
the flame safeguard control.
CHECKOUT
Perform the pilot turndown test as described in the Flame
Safeguard Control Instructions to ensure the pilot flame is
adequate to ignite the main burner.
CAUTION
Check to ensure the main valve opens only when
the pilot flame is strong enough to ignite the main
burner. Perform the pilot turn-down test as
described in the Honeywell Flame Safeguard
Control instructions.
W136A VOLT-
OHMMETER
W136A SELECTOR
SWITCH
196146 METER
CONNECTOR
PLUG
The proper pilot burner orifice must be selected for the gas
being used (natural, LP gas) so that the pilot burns with a
medium hard flame. This type of flame provides the maximum
flame signal.
PLUG
FLAME SIGNAL
METER JACK
The flame safeguard control relay will chatter if excess
secondary air velocity or a severe draft condition causes the
pilot flame to make intermittent contact with the flame electrode
(rod) or grounding bracket.
PLUG-IN FLAME
SIGNAL AMPLIFIER
The performance of the pilot assembly can be determined by
measuring the flame signal developed with the pilot operating.
The flame signal (current/voltage) measurement requires the
use of an appropriate volt-ohmmeter.
RED (+)
METER
LEAD
RED CONNECTOR
BLACK CONNECTOR
BLACK (–) METER LEAD
M6532A
Most existing Honeywell Flame Safeguard Controls
Fig. 4. Measuring microamp flame signal.
incorporate a flame current jack in the control plug-in amplifier
or in the control itself. The flame current measurement can be
made with a Honeywell W136A Test Meter, which has a 0 to 25
microampere dc scale (see Fig. 4). With the W136A selector
switch positioned to the 0 to 25 microampere scale, connect
the meter leads to the two ends of the meter connector plug,
positive (red, +) to positive, negative (black, -) to negative. The
Meter Connector Plug part no. 196146 is provided with the
W136A Meter. If a W136A Meter or connector plug is not
Pilot Turndown Test
If the flame rod is used to prove a pilot flame before the main
fuel valve(s) can be opened, perform a pilot turndown test.
Follow the procedures in the Instructions for the appropriate
Flame Safeguard Control, and in the burner manufacturer’s
instructions.
5
60-2032—4
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