RBI FUTERA XLF Series, Installation And Operation Instructions Manual

Page: 27 / 44

F d b b l & h B l M l Finned copper tube gas boilers & water heaters – Boiler Manual
27
F F
Verify low fi re operation
1. Connect a manometer or Magnehelic gauge with the pressure
side to the manifold pressure port and the other to the manifold
reference port. See Figure 18, page 26 for locations.
2. Set Honeywell R7800 control to RUN position. Th e boiler will
operate at low fi re because the low fi re switch is in the low fi re
position.
3. Measure the fl ue gas CO
2
with the boiler running at low fi re. Set
low fi re CO
2
to 8.0% – 8.5% by adjustment on the Dungs valve
using a 3mm Allen wrench.
a. Turn the wrench in small increments (10 degrees at a time).
b. Allow time aft er each adjustment for the boiler to reach steady
state.
4. Aft er sett ing the CO
2
, measure the pressure signal,
Ps
.
a. Press the
Ps (signal)
button and read the pressure. The
pressure at low fi re should be as shown in Figure 13 .
b. If the pressure is outside this range, follow instructions in the
XLF Control IOM to calibrate the fi ring rate. Increase rate if
the pressure signal is low, or decrease rate if the signal is high.
c. Return to step 1 to adjust low fi re CO
2
aft er changing low
fi re fi ring rate.
If using a U-tube manometer turned sideways for low
pressure readings, you MUST turn the manometer
upright before attempting to measure pressures at
other than low fi re. Pressure signal will reach up to 9
inches when the boiler is at high fi re, and can cause
fl uid to be pulled out of the manometer into the boiler.
Should this occur, immediately shut down the boiler
and contact the factory for procedure. Preferably, use
a Magnehelic gauge instead of a U-tube manometer to
measure the pressure to avoid this potential hazard.
Table 13 Pressure signal (Ps) (Nat Gas)
Firing
rate
%
XLF-2500 XLF-3000 XLF-3500 XLF-4000
Signal
Inches w.c.
Signal
Inches w.c.
Signal
Inches w.c.
Signal
Inches w.c.
100% -9.40 -5.50 -5.80 -8.70
20% -0.60 -0.25 -0.40 -0.40
To determine signal in mm w.c., multiply signal pressure by 25.4.
For LP Gas: All units are tested at factory. LP Combustion Values are
located on Combustion Data label.
To ensure proper boiler operation, boilers that use
room air must not be fi red at less than 33 % input.
5. Observe the burner fl ame aft er sett ing low fi re. Make sure the
fl ame is stable, but not too tight on the burner (causing infrared
operation).
DO NOT LEAVE THE BURNER IN AN INFRARED STATE
.
A few random speckles of red are acceptable, but large
concentrations of spots or large areas of red are not.
If large amounts of red concentrations are observed,
verify combustion readings.
Leave the manometer connected to the test manifold.
It will be needed for high fi re operation testing.
Verify high fi re operation
1. Jumper the AA terminals on the HeatNet board and allow the
boiler to rise to maximum (100%) input.
2. Allow the boiler to reach steady state combustion at high fi re.
3. Verify high fi re blower speed as follows:
a. With the manometer (or gauge) connected to the test manifold,
press the
Ps (signal)
butt on and read the pressure.
b. Th e pressure at low fi re should be as shown in Figure 13 .
c. If the pressure is NOT correct, follow step 4.
4. If the high fi re signal pressure is not correct:
a. Remove the jumper on A-A. Th e boiler will return to low fi re.
b. Follow the instructions in the XLF Control IOM to calibrate
the high fi re fi ring rate. (Slide the HeatNet control calibrate
switch to
CAL
. Follow the Control IOM procedure to
navigate to the HeatNet control calibration screen.)
Th e maximum fi ring rate value in the HeatNet control
is factory set at 90%. At this sett ing, at sea level, and
with typical vent length, the
boiler will be at rate
.
DO NOT increase the HeatNet control's maximum
rate sett ing above 90% unless needed for high altitude
installations.
c. If
Ps
is too high, reduce the HeatNet control's maximum
fi ring rate sett ing by 2%. Th en slide the calibration switch to
NORMAL
and exit the HeatNet control's calibration screens.
Replace the jumper on A-A and allow the boiler to return to
high fi re. Return to step 2 to repeat the process. If necessary,
repeat this sequence, reducing the fi ring rate by 2% each time.
d. If
Ps
is too low, increase the fi ring rate sett ing by 2%. Th en
slide the calibration switch to
NORMAL
and exit the
HeatNet control's calibration screens. Replace the jumper
on A-A and allow the boiler to return to high fi re. Return to
step 2 to repeat the process. If necessary, repeat this sequence,
increasing the fi ring rate by 2% each time.
e. Check the pressure signal again. If the signal is now correct,
reconnect the jumper on AA and proceed to step 5.
f. If the pressure signal is still not correct, verify that the air
trim adjustment (see Figure 19, page 26) is in the half-open
(factory setting) position. If it is at factory setting, you
will need to contact technical support at the factory to
troubleshoot the pressure signal issue.
5. If the pressure signal is correct, measure the flue gas CO
2
. It
should be between 9% and 9.5%.
a. If
CO
2
is correct, proceed to step 6.
b. If CO
2
is not within this range, adjust the air trim adjustment
slightly (see Figure 19, page 26) on top of mixing box to
achieve a CO
2
of 9% - 9.5%.
c. If adjusting the air trim adjustment does not correct the
problem, contact technical support at the factory to
troubleshoot the problem.