Endurance | Page 33 |
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flowing through the DHW heat exchanger and therefor the DHW will not be heated.
To test the switch, place a temporary jumper across the back of the connector on the PCB (see wiring diagrams for connector location). If the internal pump operates and there is DHW generated then the water flow switch is faulty and must be replaced. Note: Switch orientation is critical for proper switch operation, The identification plate on the switch must face up and the arrow on the plate must point in the direction of flow.
Failure of the mixing valve will allow cold water to be mixed with the hot water from the DHW heat exchanger during a DHW draw regardless of the setting of the mixing valve or the temperature of the water leaving the DHW heat exchanger. The failure can be detected by observing the temperature of the three pipes connected to the mixing valve. If the “mix” temperature is luke warm or cool and the “hot” temperature is hot and the “cold” temperature is cold then the mixing valve is either faulty or incorrectly adjusted and must be replaced or adjusted.
DHW heat exchanger scaling may occur in some areas of the country where there are high concentrations of minerals in the water. These minerals may cause fouling of the DHW heat exchanger over an extended period of time (lime build up). Other minerals, which react more quickly in well
systems (mostly magnesium), cause slime on the inside of the heat exchanger and prevent adequate heat transfer. These minerals must be filtered out by a special incoming water filter or by the addition of an inhibitor to protect the coil and provide acceptable water quality. Minerals may be removed when necessary by flushing the coil with a cleaner such as “Unlime®” or “Sizzle®”.
10E. High Gas Consumption
Boilers 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, boilers operating with low CO2 (especially LP boilers) 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) can not be accomplished. However, by briefly sniffing the flue gases it is possible to determine if the CO2 or O2 is within the proper range. There is no significant flue gas odor when combustion is proper. A strong piercing smell indicates poor combustion and generally a lean mixture (low CO2). Check gas valve calibration (offset adjustment) and adjust if indicated. Do not attempt to correct combustion by reorificing without an O2 or CO2 kit.