Weil-McLain WM97+ - Page 31

CWH companion water heater — Product Manual
Troubleshooting (continued)
1 Undersized water heater?
• There are many methods of sizing various applications, i.e. ASHRAE sizing tables or ASPE domestic water
heating design manual.
• Confirm the water demand required for the application.
• Confirm the flow rates of the fixtures.
• For example, was the tank sized for shower heads at 2.0 gpm, while the actual heads are 5.0 gpm?
• Use a bucket and a stopwatch to determine fixture flow rates.
• Evaluate the hot water usage pattern for a day.
• Is the peak demand unusually high for the application?
• Has the demand for domestic hot water changed since the system was installed?
• A bathroom remodeling project — new shower fixtures or a whirlpool tub would substantially change
the domestic water demand.
• New appliance added, such as a dishwasher or clothes washer?
2 Boiler system improperly sized?
• Can the boiler provide the required output to meet the domestic water load?
• Have a qualified service technician determine the domestic water heating load.
• Compare to the capacities listed at the end of this manual to ensure the WM97+ boiler and CWH
water heater are correctly sized.
3 Check component parts.
• Is the WM97+ control set properly and operating correctly?
• Review WM97+ Boiler manual and this manual to check control settings.
• If water heater control is set to “SCHEDULE,” check whether the problem is occurring during times
when the operating mode is set to Economy.
• Try changing operating mode to “High-performance.”
• During a call for heat by the water heater, does the CWH circulator begin pumping, does the boiler fire?
Check all components in the system to ensure they are properly functioning.
4 Check boiler operating temperatures.
• If possible, increase the boiler operating temperature to 180°F or 190°F or increase tank storage tempera-
ture. Read the boiler manual and this manual for adjustment instructions and WARNINGS.
• Maintain a minimal temperature in the boiler during non-heating seasons.
• A boiler typically has a higher standby loss than the indirect water heater.
• After a long standby period, the colder boiler may absorb the stored energy within the water heater
during the initial call for heat.
Insufficient hot water
Part number 635-500-156/0113
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