LAARS 9600 CB - Installation, Operation and Maintenance Instructions - Manual (Page 12)

Page 12
LAARS Heating Systems
1.19 Operating Checklist
(also see page 19)
a. Be sure that system has been filled properly (see
above) and is leak tight.
b. Open gas cock(s) and open manual gas shutoff
valve by turning to “on” position (see Figure 15).
c. Turn on main switch, set thermostat to call for
heat.
d. Blower should come on (blower will come on
immediately if system has no zone valves).
e. NOTE: Burner may not ignite on first attempt
because of air contained in gas lines. In this case
blower will stop after 4 minutes. Should this
happen, turn off main switch. Wait five minutes
and turn on switch again.
f. After placing the boiler in operation, the burner
safety shutoff device must be tested. To test,
disconnect ignitor plug at ignitor. Attempt to
start appliance. After the burner control has
completed three complete cycles the gas valve
must not open again and the VALVE / FLAME
light on the burner control must flash. Failure to
operate in this manner must be corrected by a
qualified service contractor or gas company.
Caution
Should any pronounced odor of gas be detected or if
the gas burner does not appear to be functioning in a
normal manner, close main shut off valve and contact
your heating contractor, gas company or factory
representative.
g. Check burner input (natural gas). Unit should be
in operation for 5 minutes before checking input
and all other appliances served by the gas meter
should be shut off. Determine the time required
for meter to deliver one cubic foot (CF) and
compare to Table 4.
*Most propane installations do not have a gas meter.
If CO2 or O2 is adjusted, input will be correct.
h. If the input rate is in this range proceed to 9.
Due to the effects of altitude and other minor
variations, it is possible the input will not fall
within this range and the gas orifice should be
replaced.
Changing Gas Orifice:
A CB tune-up kit is available from your supplier.
It contains a larger (marked +) and smaller
orifice (marked -). If the firing rate is low,
install the larger (+) diameter orifice. Shut off
electricity and gas to the unit. Loosen the gas
orifice union (Figure 16) and move the lower
half of the union far enough to the side to
remove the orifice. Change orifice. Reassemble,
turn on gas and power and recheck the burner
input.
i. It is recommended that the unit be checked with
a standard CO2 or oxygen tester. Insert tester
probe into the test port provided at the front of
the boiler in the exhaust vent pipe. Readings
should be:
CO
2
- 8% to 8.75% (natural gas)
O
2
- 6.9% to 5.5%
CO
2
- 9.25% to 9.75% (propane gas)
NOTE: This is a sealed combustion unit with
the air orifice and gas valve factory set. They must not be
altered or adjusted. If the firing rate cannot be obtained
with the orifices supplied or if CO2 or O2 readings do not
fall within the above ranges, contact the factory.
j. Using the temperature and pressure gauge, check
the unit outlet temperature after three to four
minutes of operation. Minimum operating
temperature is 160° F.
*If the unit will not stay on this long, open all zone
valves.
k. Shutdown Instructions:
Turn off all Electrical power to the unit at reset
switch.
Turn gas cock dial to “off” position.
1.20 Anti-Freeze and Corrosion Protection
Proper precautions for freeze protection are
recommended for boiler installations in areas where
the danger of freezing exists.
Power outage, interruption of gas supply, failure
of system components, activation of safety devices,
etc., may prevent a boiler from firing. Any time a
boiler is subjected to freezing conditions, and the
boiler is not able to fire, and/or the water is not
able to circulate, there is a risk of freezing in the
boiler or in the pipes in the system. When water
freezes, it expands. This can result in bursting of pipes
in the system, or damage to the boiler, which could
result in leaking or flooding conditions.
Table 4. Input Rate.
Input/Rate
Elapsed Time/CF
Model Number
(BTU/HR)
(Sec) (Based on
1000 BTU/CF Gas)
CB 150
150,000/147,000
23.5 to 24.5
to 153,000
CB 175
175,000/171,500
20.2 to 21.0
to 178,500
CB 200
199,900/195,900
17.7 to 18.4
to 203,900
CB 250
250,000/245,000
14.1 to 14.7
to 255,000