Bradford-White Corp BWCV warranty SECTION Trouble Shooting, Resolving Lockouts, Short Cycling

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Page 34 Bradford White

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 flow. 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 flow, 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 flue gas odor. The odor may result from an improper gas/air ratio (high or low O2 or CO2). Copper Brute II appliances operate best with 45% excess air (8% CO2 on natural gas, 9.2% CO2 on LP). Check the CO2 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.

8.2Delayed 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.

8.3Short 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-fired 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 flow through the water heater. The cause should be determined and corrected.

8.4High 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 CO2 is high (or O2 is low), appliances operating with low CO2 or high O2 (especially LP appliances) consume more gas. Adjust the CO2 or O2 for optimum efficiency. If no combustion analyzing equipment (CO2 or O2) is available then a proper adjustment of the air/fuel ratio (CO2 or O2) cannot be accomplished. However, by briefly sniffing the flue gases it is possible to determine if the CO2 or O2 is within the proper range. No significant flue gas odor should be detected when combustion is proper. A strong piercing smell indicates poor combustion and generally a lean mixture - low CO2 or high O2 . The CO2 should be 8% at high fire. To check the CO2, first 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 firing, 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 final adjustment is made.

8.5Troubleshooting the Temperature Control

A trouble shooting chart for the temperature control is shown on the following page.