Adjusting Combustion - Laars FT Series Installation And Operation Instructions Manual

The FT Series Floor Standing, Combination Boiler

4.13 Adjusting Combustion

1. Remove the front cover by opening the two clips
on the top of the boiler front cover - tilt forward
and lift the cover off.
2. Turn ON the GAS and WATER supply to the FT.
3. Turn ON the FT.
4. Ensure your FT is set for the correct altitude. The
default setting is for altitudes of 0~1,999 ft above
sea level. If your FT floor is installed at an altitude
of 2,000 ft,or greater the correct altitude setting
should be set according to Section 4.13 of the FT
Install and Operating Manual (Floor) before you
continuing tuning this unit.
5. Check gas inlet pressure at inlet pressure port.
(See previous page).
6. Establish a call for heat. You may need to
disconnect the outdoor reset if you are making
this gas conversion during warm weather.
7. Connect a manometer to the manifold pressure
port. For dual port manometers, use the positive
pressure side. Check for proper manifold gas
pressure. Refer to Table 11, page 38.
8. Setup your combustion analyser and place the
sensor into the combustion test port
9. Per Section 4.14 for Max Fire, change dip switch
6 to ON. The unit will cycle up to MAX fire.
10. WAIT for your combustion analyser to stabilize.
This may take up to 3 minutes depending on
your combustion analyser. Then check the CO 2
measurement for MAX Fire. Refer to Table 10 for
acceptable MAX fire combustion readings Do
NOT attempt to adjust CO 2 at MAX Fire.
ONLY adjust CO 2 in MIN Fire operation.
11. For MIN Fire, change dip switch 6 to OFF and 7 to
Standard Factory Setting is for MAX Fire. 9.0%
CO2 @ 0-2,000 ft altitude (Natural Gas).
CO
2
FTCF (ALL Sizes)
( and all altitudes)
Table 10. CO 2 Values
value
2˝ VENT
MAX FIRE
MIN FIRE
ON. The unit will cycle down to MIN Fire.
Note: When in Low Fire the burner should remain
on. If the flame dies out after a few seconds while in
Low Fire the gas input to the burner is too lean and
will need to be increased slightly by using the offset
adjustment. Turn the offset adjustment 1/8" clockwise
and allow burner to cycle. Only adjust clockwise until
the burner is able to remain lit. Once stable on Low
Fire continue onto Step 12.
12. WAIT for your combustion analyser to stabilize.
Then check the CO 2 measurement for MIN
fire. Refer to Table 10 for acceptable MIN fire
combustion readings
13. Open the Gas Valve Adjustment Port by removing
the cap screw with a # T15 wrench.
14. Then use the # T15 wrench to make a minor
adjustment (1/8 turn) to either increase or
decrease CO2. See 4.12 on page 36.
15. It may be necessary to go back and forth between
HI Fire and LOW Fire several times (and adjusting
only at LOW Fire), before CO2 at both are within
acceptable levels. Be sure to put the adjustment
port cap screw back onto the valve when done.
16 Once the CO2 and manifold pressure
measurements for both MIN and MAX Fire are
acceptable per Table 10, set DIP switches 6
and 7 to the OFF position for Nominal Fire
(normal operation).
17. Remove your combustion analyser from the Test
Port and be sure to thread the Test Port plug back
into position.
18. Re-connect outdoor reset if it was disconnected,
put the boiler cover back on and secure the clips
that hold the cover in place.
WARNING
Installer is required to verify combustion settings as
part of the installation process.
Natural Gas (NG)
3˝ VENT
8.5 - 10.5%
8 - 10%
Propane Gas (LP)
2˝ VENT 3˝ VENT
9.5 - 11%
9 - 10.5 %
Page 37