750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual
6-5
6.5 — Burner Operating Controls: General
1.
Operating Limit Control:
Senses temperature or pres-
sure and automatically turns the burner on to initiate the
startup sequence when required and turns the burner off to
initiate the shutdown sequence when the demand is satis-
fied. The control must be set to initiate startup only at the
low-fire position.
2.
High Limit Control:
Senses the hot water temperature
or steam pressure. It is used as a safety limit to turn the
burner off in the event the operating limit control fails. The
high limit control should be set sufficiently above the oper-
ating limit control to avoid nuisance shutdowns, because it
has a manual reset feature
FIGURE 6-4.
Steam Operating Controls
3.
Modulating Control:
Senses changes in the hot water temperature or steam pressure and signals the modulat-
ing motor to control the flow of fuel and air to the burner. With either steam or hot water boilers, the modulat-
ing control must be set to ensure the burner is at its minimum low-fire position before the operating limit
control either starts or stops the burner.
When adjusting or setting controls, first be sure all control devices are securely mounted and level. With the tem-
perature sensing control, make sure the sensing bulb is properly bottomed in its well and is secured against move-
ment. Be sure the connecting tubing is not kinked.
The dial settings are generally accurate, although it is not unusual
to have a slight variation between a scale setting and an actual pres-
sure gauge or thermometer reading. Always adjust control settings
to agree with pressure gauge or thermometer readings. Accurate
instrument readings are required. When necessary use auxiliary test
equipment to set controls.
FIGURE 6-5.
Hot Water Controls
Burner controls correctly set to match load demands will provide operational advantages and achieve the following
desirable objectives:
•
The burner will be operating in low-fire position prior to shutdown.
•
The burner will operate at low-fire for a brief period on each start during normal operation.
•
Eliminates frequent burner on-off cycling.
Содержание 4WI
Страница 46: ...Burner Operation and Control 2 22 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Страница 62: ...Waterside Care and Requirements 3 16 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Страница 70: ...Sequence of Operation 4 8 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Страница 114: ...Adjustment Procedures 6 28 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Страница 192: ...Parts 9 38 750 211 revised 2009 Promethean Boilers Model 4WI Manual 9 2 27 General Control Panel 60 106 100 800 HP...
Страница 196: ...Parts 9 42 750 211 revised 2009 Promethean Boilers Model 4WI Manual 9 2 29 Main Gas Train 60 106 100 800 HP...
