Installation manual

42
F. TEST HIGH LIMIT CONTROL AND ADJUST
While burner is operating, move indicator on
high limit control below actual boiler water tem-
perature. 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. Maxi-
mum high limit setting is 200
°
F. Minimum high
limit setting is 100°F.
G. 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.
H. SET THERMOSTAT HEAT ANTICIPATOR (IF USED)
AND VERIFY THERMOSTAT OPERATION
For a single thermostat connected to the yel-
low thermostat lead wires in the furnished field
wiring junction box, the heat anticipator should
be set at 0.7 amps. For other wiring configura-
tions, refer to the instructions provided by the
thermostat manufacturer regarding adjustment
of heat anticipator. Cycle boiler with thermo-
stat. 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.
I. MEASURE THE NATURAL GAS INPUT RATE
Correct input rate is essential for proper and
efficient operation of the burner and boiler.
1. Determine elevation at installation site.
2. See page 6 and 7 of this manual to de-
termine the correct input rate for the local
elevation.
3. Obtain the yearly average heating value of
the local gas supply from the gas utility. At
sea level elevation, it should be approxi-
mately 1000 Btu’s per standard cubic foot.
4. Operate boiler for 5 minutes.
5. Turn off all other gas appliances, extinguish-
ing standing pilots where applicable.
6. At gas meter, measure time in seconds re-
quired to use one cubic foot of gas.
7. Calculate input rate according to the follow-
ing formula:
3600xheating value from step 3
Btuh inputrate = time from step 6
8. Measured input rate should be within +/-2%
of the input rating from step 2. If within 2%,
go to step 9. If not, adjustment is required,
proceed as follows:
a. Turn boiler off
b. Set up U-tube manometer or differential
pressure gauge for measuring manifold
pres sure, 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 ad-
justment. Manifold pressure reading will
change (increase) when cover screw is
removed.
CHECK OUT PROCEDURE AND ADJUSTMENT