Adjustment Procedures
6-10
750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual
6.12 — Low Water Cutoff Devices: Steam and Hot Water
No adjustment is required since LWCO controls are preset by the original
manufacturer. However, if the water level is not maintained, inspect the
devices immediately and replace as required.
FIGURE 6-9. Low Water Cutoff
6.13 — Combustion Air Proving Switch
Air pressure against the diaphragm actuates the switch which, when made, com-
pletes a circuit to prove the presence of combustion air. since the pressure of the
combustion air is at its minimum value when the damper is full open, the switch
should be adjusted under that situation. It should be set slightly below the mini-
mum pressure, but not too close to that point to cause nuisance shutdowns.
The run/test switch on the program relay should be set to “Test.” Turn the
burner switch on. The blower will start (provided that all limit circuits are com-
pleted) and the programmer will remain in the low-fire (damper closed) portion
of the pre-purge.
FIGURE 6-10. Combustion Air Proving Switch
To have the modulating damper motor drive to high-fire (damper open), remove the cover from the motor and
remove the wire from terminal W.
Slowly turn down the air switch adjusting screw until it breaks the circuit. Here the programmer will lockout and
must be manually reset before it can be restarted. Add a half turn or so to the adjusting screw to remake its circuit.
Recycle the program relay to be sure that normal operation is obtained. Replace the wire on terminal W and re-
install the cover. Return the test switch to the “Run” position.
To Next Page
Loading...
