McDonnell & Miller 101A Water Feeder

For service professionals managing residential or light commercial low-pressure steam systems, the McDonnell & Miller 101A (Part Number 169400) remains a staple for automated level control. This 120Vac electric water feeder is specifically engineered for cold water feed applications, eliminating the need for manual monitoring and adding water to the boiler. Designed with a heavy-duty solenoid, this unit handles a 150 PSI maximum water supply pressure and is compatible with boilers operating up to 25 PSI max pressure.

The 101A integrates seamlessly with both mechanical and electronic low water cut-off (LWCO) controls, ensuring the burner circuit remains protected while maintaining the minimum safe water level. A standout feature for the field technician is the quick-change replaceable cartridge valve and integrated strainer, which allows for rapid maintenance in the event of sediment buildup without necessitating a full teardown of the piping. With a power consumption rating of 40 VA and 1/2" NPT threaded connections, this feeder supports systems with capacities up to 2,350,000 BTU/hr, providing a robust solution for maintaining the hydronic balance of your steam heating loop.

Key Benefits for Contractors

• Automated Hydronic Leveling: Significantly reduces nuisance service calls by automating steam boiler water feeding in response to LWCO signals.
• Contractor-Friendly Maintenance: Features a manual feed button for system priming and a field-replaceable CTRD-101 cartridge kit to simplify internal valve repairs.
• High-Capacity Performance: Rated for systems up to 5,000 sq. ft. EDR, providing a flow rate of approximately 2.1 GPM at a 20 PSI differential.
• Solenoid Reliability: High-torque 120V solenoid ensures positive shut-off and consistent operation under varying pressure differentials.

Common Technical Questions

Can the 101A be used with a manual reset low water cut-off?
No, this water feeder should only be used with automatic reset LWCOs. Using it with a manual reset control can lead to overfilling or flooding conditions since the feeder will attempt to add water while the burner circuit remains locked out.

What is the maximum inlet water temperature for this unit?
The McDonnell & Miller 169400 is designed for cold water feed. The maximum allowable temperature for the inlet water is 120°F (49°C). Exceeding this temperature can cause premature failure of the internal seals and solenoid components.

Why is the feeder humming but not adding water to the boiler?
If the solenoid is energized (humming) but no flow is present, the strainer basket or valve cartridge is likely obstructed by scale and sediment. First, attempt to use the manual feed override. If flow remains blocked, the replaceable cartridge and strainer must be cleaned or swapped.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.