Laars NeoTherm NTH Installation And Operation Instructions Manual - page 30
LAARS Heating Systems
Page 30
label and turn on gas and electrical power to
appliance.
4.
NeoTherm will enter the start sequence. Blower
and pump will energize for pre-purge, then the
ignition sequence starts. After all safety devices
are verified, the gas valve opens. If ignition
doesn’t occur, turn off the NeoTherm, check that
there is proper gas supply. Wait 5 minutes and
start the unit again.
5.
Turn NeoTherm on.
6.
After placing the appliance in operation, the
Burner Safety Shutoff Device must be tested
:
(a)
Close gas shutoff valve with burner operating.
(b)
Flame will go out and blower will continue to
run for the post purge cycle. One or three
additional attempts to light will follow
including pre-purge, ignitor on, valve/flame on
and post purge. Ignition will not occur as the
gas is off. The ignition control will lockout.
(c)
Open gas shutoff valve. Reset the boiler
control by pressing the
RESET
button on the
control or on the display. Restart the
appliance. The ignition sequence will start
again and the burner will start. The appliance
will return to its previous mode of operation.
Caution
Should any odor of gas be detected, or if the gas
burner does not appear to be functioning in a normal
manner, CLOSE MAIN SHUTOFF VALVE. Do not
shut off switch. Contact your heating contractor, gas
company, or factory representative.
6.2.2 Boiler Setup and Adjustment
1.
Connect a manometer capable of reading -.005"wc
to the gas valve locations shown in
Figure 25
. The
positive side of the manometer should be
connected to the location labeled “air pressure
tap.” The negative side of the manometer should
be connected to the location labeled "gas pressure
tap." This differential pressure should be slightly
negative (see
Table 13
).
2.
Measure the CO
2
/O
2
in the flue products at high
fire. The NeoTherm can be forced to high fire to
allow for easier setup. Refer to Section 5.2.3 for
instructions on how to access the forced rate menu.
The CO
2
readings should be between the values
shown in
Table 13
. If the CO
2
is not within the range
shown, adjustments may be made. To adjust the high
fire CO
2
, locate the high fire adjuster screw according
to the appropriate figure. Slowly make adjustments in
Figure 25A. NeoTherm Gas Valves (285, 399 and 500).
80–285
399
500
GAS TYPE
CO
2
HIGH FIRE
LOW FIRE OFFSET
Natural Gas
8.9 – 9.1%
0.5 to 0.75% less than high fire
Propane Gas
9.9 – 10.1%
1.0 to 1.5% less than high fire
Table 13. CO
2
Range.