Bradford-White Corp BWCV Water Heater User Manual


 
Internet Version for Reference Only
Bradford White
Page 34
Copper Brute II
Page 35
10. Inspect the inside of the copper tubes for scale
buildup. Scale can build up on the inner surface
of the heat exchanger tubes, which can restrict
water ow. If the tubes show signs of scaling,
clean the internal surface. Bradford White offers
a tube cleaning kit part number R0010000.
11. Reassemble in the reverse order, and check
appliance operation after start-up.
NOTE: The Warranty does not cover damage
caused by lack of required maintenance, lack of
water ow, or improper operating practices.
SECTION 8.
Trouble Shooting
8.1 Resolving Lockouts
There are many causes of lockouts. The three
most common causes are: (1) inadequate gas supply,
(2) poor combustion, (3) ignitor failure.
1. Inadequate gas supply: Before proceeding, ensure
that the gas supply has not been shutoff or the LP
tank (LP heaters) is not empty. Then, restart the
heater and observe the operational cycle. After
a 15-second fan pre-purge, the ignitor will heat
up for 20 seconds, and then the unit will light.
If it does not, check the gas supply pressure to
the appliance, after resetting the appliance and
attempting another start-up. The gas pressure to
the appliance must be above 5" W.C. (1.2kPa)
throughout the entire start-up cycle. If it is not,
correct the supply problem (check gas valves or
supply piping). If the supply pressure is adequate,
consult the factory for assistance.
2. Poor Combustion: Poor combustion should
be suspected if there is a strong ue gas odor.
The odor may result from an improper gas/air
ratio (high or low O
2
or CO
2
). Copper Brute II
appliances operate best with 45% excess air (8%
CO
2
on natural gas, 9.2% CO
2
on LP). Check the
CO
2
of the appliance and adjust if necessary.
3. Ignitor failure: If the heater goes through a
normal start cycle but combustion does not
occur, ignitor failure should be suspected. Check
the ignitor by unplugging the ignitor plug and
measuring the ignitor resistance. It should be
50-80 ohms. If the resistance is not 50-80 ohms,
replace the ignitor. If the resistance is correct,
reset the heater and check for 120 VAC at the
ignitor plug during the start cycle. If there is no
voltage, replace the faulty ignitor wire harness or
the ignition control.
8.2 Delayed Ignition — Possible Causes
A defective burner can cause a delayed ignition.
If the gas supply pressure is proper and the gas
valves are functioning properly, then burners should
be inspected. There should be no distortion or
perforations in the burners outside of the active burner
port area. Replace if indicated.
8.3 Short Cycling
Short cycling will generally occur only in
combination space heating and water heating
applications when the water heater is operating in the
space-heating mode. Because the Copper Brute II is a
stage-red water heater and its input will reduce when
there is a reduction in heating load, short cycling is
greatly reduced. If the heating load drops below the
minimum input of the water heater for an extended
period, the water heater will have a tendency to short
cycle. If short cycling is frequently experienced,
regardless of the control’s attempt to limit it, the
heating load should be redistributed to control it. See
Section 6.2 regarding controller setup.
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
ow through the water heater. The cause should be
determined and corrected.
8.4 High Gas Consumption
Appliances operating with an improper air/fuel
ratio are very inefcient and consequently, have
very high gas consumption. Because efciency 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 efciency. 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. However, by briey snifng the ue
gases it is possible to determine if the CO
2
or O
2
is
within the proper range. No signicant ue gas odor
should be detected when combustion is proper. A
strong piercing smell indicates poor combustion and
generally a lean mixture - low CO
2
or high O
2
. The
CO
2
should be 8% at high re. To check the CO2, rst
verify that the supply gas pressure is within 5" to 13"
w.c. (1.2 to 3.2 kPa) With the heater running with all
stages ring, set the air box pressure to 1.5" w.c. (0.37
kPa) (as a starting point), by adjusting the air shutter(s)
at the bottom of the fan(s). Check the CO2, and adjust
the air shutters if further adjustment to the CO2 is
needed. Models 1250 to 2000 have two blowers and
two air chambers (boxes). The pressure of each air box
must be equal when the nal adjustment is made.
8.5 Troubleshooting the Temperature
Control
A trouble shooting chart for the temperature
control is shown on the following page.