Weil-McLain C-1013 Troubleshooting Manual page 6

- What is the location of the thermostat bulb? A bulb inserted completely at the bottom of
the drywell will initiate a quicker response for a call for heat. This is typically the position
of the bulb required for applications in which there are large draws of domestic water.
- Remove and examine the dip tube located in the cold water inlet. Replace if damaged. A
broken or melted dip tube will cause the cold water to discharge across the top of the tank,
thus short cycling the water heater.
Check the operating temperature of the boiler (Non-Warranty)
- If possible increase the boiler operating temperature to 200ºF.
- 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.
Check location of flow control devices (Non-Warranty)
- Lab tests have shown that during long standby periods the boiler piping can act as a
thermal siphon and draw stored heat from the domestic water. Locate flow control devices
(zone valve, spring check valves...) or heat trap loops in the boiler piping close to the water
heater. Insulate all boiler piping to and from the water heater.
Check for air in the system (Non-Warranty)
- An air bound water heater or boiler will not circulate system water properly, resulting in a
lack of heat transfer.
Clean the boiler system (Non-Warranty)
- A dirty boiler system can cause deposits to form on the outer wall of the inner tank, which
insulates the tank, affecting the heat transfer. Clean the boiler system per the boiler's
manufacturer's instructions.
Action Item:
- Install a strainer in the boiler piping on older installations or for systems prone to
becoming dirty.
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