Lochinvar 000 through 2, 1 warranty Table P, Bypass Operation, Minimum Water Temperatures

TABLE - P

Temperature Rise At Full Rate Fire

Bypass Manually Fully Closed

Btu/hr Input	Temperature Rise
1,500,000	31.5°F (17.5°C)
_______________________	_______________________
1,700,000	35.7°F (19.8°C)
_______________________	_______________________
2,000,000	42.0°F (23.3°C)

NOTE:

The Excel 10 controller makes all internal calculations in °C and converts the displayed temperature to °F. This may limit exact temperature adjustment. Setting of temperature rise to the nearest °F is acceptable when setting maximum flow.

Turn off power to the appliance. Reconnect the power leads to the bypass actuator. Turn power on and place the run/stop switch in the run position and allow the bypass valve to go through the synchronization process before it begins normal operation.

WARNING￿

Moving the bypass handle while appliance is firing can result in abnormally high water temperature that may cause sudden relief valve discharge.

BYPASS OPERATION

1.Main burner ignition is achieved.

2.Integral bypass begins the adjustment process to control inlet water temperature to the primary heat exchanger.

3.The Excel 10-controller senses inlet water temperature to the primary heat exchanger.

4.Inlet water temperature into the primary heat

exchanger is displayed as “Bypass Temperature” in one of the 21 points on the Command Display.

5.The floating-point bypass valve begins to adjust position to maintain an inlet temperature to the primary heat exchanger above the dew point of flue products.

6.Minimum inlet water temperature to prevent condensation of flue products is fixed at 130°F (54.4°C). This control point is programmed into the software in the Excel 10 controller.

7.The Excel 10 provides 24 VAC to operate a high torque motor in the actuator, which adjusts the position of the floating-point bypass valve.

8.The actuator for the bypass valve adjusts in as many as 500 micro-steps to achieve the desired water temperature at the inlet to the primary heat exchanger.

9.With each micro-step of movement in the position of the valve, the Excel 10 checks for a change in water temperature at the inlet to the primary heat exchanger. As long as the inlet water temperature is below 130°F (54.4°C) the bypass is moving toward full open to increase the inlet water temperature. When the inlet water temperature is above 130°F (54.4°C) the bypass is moving toward full closed to sustain the water temperature above the dewpoint of the flue products.

10.Operation of the bypass valve maintains water temperatures above the dew point of flue products at the primary heat exchanger to ensure that condensate formation occurs only on the secondary heat exchanger.

The use of a Floating-Point Bypass Valve means that there is no fixed open or closed position on the valve. If errant hands manually move the bypass adjustment handle, it will take longer to adjust to the proper setting but it will still function properly to main- tain water temperatures.

CAUTION￿

Failure to disconnect power to the actuator before declutching or manually moving the valve handle can cause non-warrantable damage to the actuator.

MINIMUM WATER TEMPERATURES

A minimum return water temperature of 50°F (10°C) has been established for each model based on the Btu/hr output at 100% of rated burner input. The temperature set point for the Excel 10 controller sensing system temperature or stored water temperature must not be set lower than the specified minimum for each model. Maintaining inlet water temperatures to the appliance equal to or higher than the specified minimum temperature setting ensures proper operation of the bypass and allows all condensate formation to occur on the secondary heat exchanger. An appliance allowed to sustain operation at water temperatures lower than the specified minimum temperature may not provide enough heat from the burner to maintain water temperatures in primary heat exchanger above the 130°F (54.4°C) dew point of flue products. Operation of the appliance at a temperature below the specified minimum set point temperature will result in non-warrantable operational problems from the condensate formation on the primary heat exchanger.

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