LAARS Pennant PNCV (Sizes 200, 300, 400) - Install and Operating Manual - Manual (Page 37)

LAARS Heating Systems
Page 36 Pennant 200, 300, 400 Page 37
If short cycling occurs in a water heater
application, it is probably caused by undersized
piping between the water heater and the storage tank
or by some other factor that restricts proper water
flow through the water heater. The cause should be
determined and corrected.
8.5 High Gas Consumption
Appliances operating with an improper air/fuel
ratio are very inefficient and consequently, have
very high gas consumption. Because efficiency is
high when the CO
2
is high (or O
2
is low), appliances
operating with low CO
2
or high O
2
(especially LP
appliances) consume more gas. Adjust the CO
2
or O
2
for optimum efficiency. If no combustion analyzing
equipment (CO
2
or O
2
) is available then a proper
adjustment of the air/fuel ratio (CO
2
or O
2
) cannot be
accomplished. The CO
2
should be 8% at high fire for
natural gas and 9.2% at high fire for LP. To check the
CO
2
, first verify that the supply gas pressure is within
5 to 13 in. w.c. (1.2 to 3.2 kPa). With the Pennant
running with all stages firing, set the air box pressure
to 1.8 in. w.c. (0.42 kPa) (as a starting point), by
adjusting the air shutter(s) at the intake of the fan(s).
Check the CO
2
, and adjust the air shutters if further
adjustment to the CO
2
is needed.
8.6 Troubleshooting Pennant Controls
The field wiring board along with the diagnostic
LEDs can be used to troubleshoot the Pennant
controls. Terminals on the field wiring board are
provided as test points and allow troubleshooting of
most Pennant control functions from a single location.
The terminals are identified in the Ladder Wiring
Schematic (Figure 14).
Certain control elements may be connected in the
field to the field wiring board. In addition to the ladder
wiring schematic, refer to the Connection Diagram
(Figure 13) to verify that field connections have been
made correctly.
The Pennant temperature control and ignition
control both have fault indicators. The temperature
control fault codes are shown in Table 12. The ignition
control fault codes are shown in Table 13.
Fault Code Description
NoA No acknowledged call-for-heat
signal received (K1 energizes and
the contacts close, but 24V is not
shown on the downstream side of
the K1 contact) (This code is normal
when operating in "Remote" mode.)
I-F Ignitor fault signal received from
ignition control
AFF Air flow fault
FLE Flame error – flame detected with
no call for heat
Loc Ignition lockout signal received from
ignition control
Ito Ignition time-out
P1H RT1 sensor shorted or high out-of-
range temperature signal received
P1L RT1 sensor open or low out-of-
range temperature signal received
P2H RT2 sensor shorted or high out-of-
range temperature signal received
P2L RT2 sensor open or high out-of-
range temperature signal received
Table 12. Fault Codes.
LED State Indication
Steady On Control Fault
1 Flash
Air Flow Fault
2 Flashes Flame Attempt With No Call For Heat
3 Flashes Ignition Lockout
4 Flashes Burner On
Table 13. Ignition Control LED Description
SECTION 9.
Replacement Parts
Only genuine Laars replacement parts should be used.
9.1 General Information
To order or purchase parts for the Laars Pennant,
contact your nearest Laars dealer or distributor. If
they cannot supply you with what you need, contact
Customer Service (see back cover for address,
telephone and fax numbers).
9.2 Parts List