Is the expansion tank on the boiler side properly sized?
- The additional quantity of boiler water contained in the outer tank must be considered
when sizing the boiler side expansion tank.
- Insufficient allowance for expansion on the boiler side can cause the boiler pressure relief
valve to lift.
Is the expansion tank defective, waterlogged or improperly charged?
(Non-Warranty)
- Check for failed gaskets or bladders, or a faulty Schraeder valve.
- Use a tire gauge to check the charged pressure of the tank.
Action Item:
- Turn the boiler limit up to a higher setting and let the system run at a higher temperature.
This will simulate maximum expansion in the boiler system.
- If the boiler relief valve lifts and/or there is a significant increase in the boiler system
pressure, the expansion tank is flooded or undersized.
Is the boiler pressure relief valve functioning properly? (Non-Warranty)
- Dirt and water deposits can accumulate under the valve seat.
Check the boiler automatic fill valve for defects. (Non-Warranty)
- Is the valve filling to the correct pressure?
Check for possible ‘inner tank leak’ *reason code 054
- If possible, isolate the Plus tank from the boiler system for an extended period of time.
Observe the boiler system pressure during that time.
* This may be a manufacturing defect. Please initiate a warranty claim with Weil-McLain
noting the reason code listed.
Weil-McLain Water Heater Model Boiler Side Capacity Gal.
GOLD Plus 30 5
GOLD/Ultra Plus 40 6
GOLD/Ultra Plus 60 8
GOLD/Ultra Plus 80 8
Comm. PLUS 100 Series 2/Series 3 8/14
Comm. PLUS 110 25
Comm. PLUS 119/120 43
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