Dunkirk 90-50 Installation, Operation & Maintenance Manual page 38

Test High limit Control and adjust
While burner is operating, move indicator on high limit control
below actual boiler water temperature. Burner should go off while
circulator continues to operate. Raise limit setting above boiler water
temperature and burner should reignite after pre purge and igniter
warm-up period. Set the high limit control to the design temperature
requirements of the system. Maximum high limit setting is 200°F.
Minimum high limit setting is 100°F.
Test other safety Controls
If the boiler is equipped with a low water cut off, a manual reset high
limit, or additional safety controls, test for operation as outlined by
the control manufacturer. Burner should be operating and should
go off when controls are tested. When safety controls are restored,
burner should reignite.
set Thermostat Heat anticipator (if used) and Verify
Thermostat operation
For a single thermostat connected to the yellow thermostat lead
wires in the furnished field wiring junction box, the heat anticipator
should be set at 0.7 amps. For other wiring configurations, refer to
the instructions provided by the thermostat manufacturer regarding
adjustment of heat anticipator. Cycle boiler with thermostat. Raise
the thermostat to the highest setting and verify boiler goes through
normal start up cycle. Lower thermostat to lowest setting and verify
boiler goes off.
measure The natural gas input rate
Correct input rate is essential for proper and efficient operation of
the burner and boiler.
Determine elevation at installation site.
1.
See page 6 and 7 of this manual to determine the correct input
2.
rate for the local elevation.
Obtain the yearly average heating value of the local gas
3.
supply from the gas utility. At sea level elevation, it should be
approximately 1000 Btu's per standard cubic foot.
Operate boiler for 5 minutes.
4.
Turn off all other gas appliances, extinguishing standing pilots
5.
where applicable.
At gas meter, measure time in seconds required to use one
6.
cubic foot of gas.
Calculate input rate according to the following formula:
7.
3600xheating value from step 3
Btuh inputrate = time from step 6
Measured input rate should be within +/-2% of the input rating
8.
from step 2. If within 2%, go to step 9. If not, adjustment is
required, proceed as follows:
A. Turn boiler off
CHeCk ouT proCedure and adjusTmenT
38
B. Set up U-tube manometer or differential pressure gauge for
measuring manifold pressure, see Figure #17.
C. Manometer or gauge must be able to read at least 0.0 to 3.0
inches water column of pressure, and resolve to at least 0.1
inches water column.
D. Turn boiler on.
E. Manifold pressure has been nominally set at 2.5 inches
w.c. Manifold pressure and input rate must always be
measured with pressure regulator cover screw installed.
Cover screw must be removed for adjustment. Manifold
pressure reading will change (increase) when cover screw is
removed.
F. After adjusting input rate, turn boiler off, remove
manometer or pressure gauge, reinstall ⅛" plug on gas
valve. Turn boiler on.
Restore all gas appliances that may have been shut off (while
9.
measuring boiler input rate) to normal operating conditions.
I. Remove regulator cover screw on top of gas valve, and insert
an appropriate screwdriver into adjustment screw.
II. Turn adjustment screw clockwise to increase input rate, or
counter clockwise to decrease input rate.
III. Replace cover screw, or cover hole temporarily with your
finger to check new manifold pressure setting. Do not set
manifold pressure lower than 2.0 inches w.c. or higher than 3.0
inches w.c. when adjusting input rate.
IV. Measure new input rate (cover screw must be installed).
Repeat steps I.-IV until the input rate is within +/-2% of the
nameplate input rating.
V. If the actual input rate can not be set to within 2% of the
correct input rating by adjusting manifold pressure, a change
in gas orifice size is required. Consult the boiler manufacturer
for information on correct orifice sizing. The specific gravity
(G) and the higher heating value (HHV) of the local natural
gas must be obtained from the local gas utility in order to
determine the proper orifice size.
set Thermostat To desired room Temperature
Observe several operating cycles to verify proper operation.
review all instructions
Review all instructions shipped with this boiler with owner or
maintenance person. Instructions must be affixed on or adjacent to
the boiler.
Complete and sign the installation and check-out
certificate found in this manual.