Service Hints - Carrier BW4 Installation, Start-Up, And Operating Instructions Manual

Avoid inconvenience and service calls by checking these points before calling for service.
Possible Cause
Thermostat is not set correctly
Boiler and/or burner may be dirty
Burner may not be firing at proper rate
Burner may be short-cycling
No power to boiler
Controls out of adjustment
Radiators not heating
Circulator pump not running
Poor electrical contact
Possible Cause
Oil burner fan wheel may be dirty
Draft regulator may be stuck
Possible Cause
Air in system
Possible Cause
Dirt on seat
Waterlogged expansion tank
HAVE YOUR SERVICE TECHNICIAN CHECK ANY PROBLEM YOU ARE UNABLE TO CORRECT.
All parts are listed in the following Parts Lists. Parts may be ordered through nearest supplier
When ordering parts, first obtain the Model No. from the name plate on boiler, then determine the Part No. (not the Key No.) and the
Description of each part from the following appropriate illustration and list. Parts for which no Part No. is given are standard items which
can be procured locally.
Be sure to give all this information: The Part No., The Part Description, The Boiler Model No.
240 F (116 C)
HI LIMIT
SETTING
10 F (5.6 C)
DIFF
25 F (13.9 C)
DIFF
LOW LIMIT
AND
10 F (5.6 C)
CIRCULATOR
DIFF
SETTING
110 F (43 C)
Fig. 22—Relationship of Set Points and Differential

SERVICE HINTS

IF SYSTEM IS NOT HEATING OR NOT GIVING ENOUGH HEAT. . .
What To Do
Reset thermostat above room temperature.
Clean all flue passages and vent pipe. Have burner cleaned and readjusted.
Check nozzle size it there is any doubt. Have burner adjusted.
Short-cycling (too frequent off and on) of burner causes sooting. If boiler and/or burner becomes dirty at
frequent intervals, correct the "dirt condition," then also correct the control setting (or other cause of short-
cycling).
Check thermostat heat anticipator and correct setting, if necessary, per instruction sheet packed with thermo-
stat.
Check overcurrent protection. Check to be sure power supply circuit is on.
Reset according to instructions packed with controls.
Open radiator vents to vent excess air. Check flow control valve (if used). It may be in closed position.
Check relay operation.
Check all control terminals and wire joints.
IF BURNER IS NOISY. . .
What To Do
Clean fan wheel with a stiff brush and cleaning solvent. Readjust oil burner.
Check to see if vane swings freely. Clean if vane is stuck.
IF RADIATORS ARE NOISY. . .
What To Do
Open radiator vents to vent air. Check expansion tank.
RELIEF VALVE LEAKING. . .
What To Do
Open valve manually. Allow water to run and clear valve seat.
Drain tank. See instructions.
PARTS LIST
SWITCH BREAKS ON
RISE, TURNS BURNER
OFF. CIRCULATOR
OPERATES ON CALL
FOR HEAT.
SWITCH MAKES ON
FALL. BURNER
OPERATES ON
CALL FOR HEAT.
SWITCH MAKES R-W,
BREAKS R-B ON RISE
(25 F [13.9 C]
DIFFERENTIAL).
SWITCH MAKES R-W,
BREAKS R-B ON RISE
(10 F [5.6 C]
DIFFERENTIAL).
SWITCH MAKES R-B
ON FALL, BREAKS
R-W. BURNER ON,
CIRCULATOR OFF.
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