750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual
6-11
6.14 — Atomizing Air Proving Switch
6.14 — Atomizing Air Proving Switch
The air pressure against the diaphragm actuates the switch which, when
closed, completes a circuit to prove the presence of atomizing air. Since the
pressure of the atomizing air is at its minimum value when there is no fuel
present at the nozzle, adjustment of the switch should be done while the unit
is running but not firing. The control should be set slightly below the mini-
mum pressure, but not too close to that point to cause nuisance shutdowns.
The control adjustment may be made during the pre-purge period of opera-
tion by stopping the programmer during the pre-purge period through the
use of the Test switch. Refer to the control instruction bulletin for details.
FIGURE 6-11.
Atomizing Air Proving Switch
The adjustment screw of the atomizing air proving switch can then be adjusted until it breaks the circuit. Here, the
programmer will lockout and must be manually reset before it can be restarted. Turn the adjusting screw up a half
turn or so to remake the circuit.
After making the adjustment, recycle the control to be sure that normal operation is obtained. The Test switch
must be set to the “Run” position.
6.15 — Gas Pilot Flame Adjustment
The size of the gas pilot flame is regulated by adjusting the gas flow through the pilot gas regulator and the adjust-
ing cock. The flame must be sufficient to ignite the main flame and to be seen by the flame detector. But an
extremely large flame is not required. An overly rich flame can cause sooting or carbon buildup on the flame detec-
tor. Too small a flame can cause ignition problems.
Although it is possible to visibly adjust the size of the pilot flame, it is preferable to obtain a micro amp or voltage
reading of the flame signal.
The correct voltage or micro amp readings can be found in the information supplied with the flame safeguard sys-
tem or the Hawk ICS manual 750-197.
NOTE:
On an oil fired boiler, the atomizing air proving switch (AAPS) must also be closed. This is an automatic
operation.
NOTE:
On a combination fuel fired burner, firing gas, the fuel selector switch could be set at “gas” to eliminate the
atomizing air proving switch from the circuitry.
Summary of Contents for 4WI
Page 46: ...Burner Operation and Control 2 22 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Page 62: ...Waterside Care and Requirements 3 16 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Page 70: ...Sequence of Operation 4 8 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Page 114: ...Adjustment Procedures 6 28 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
