mismatched fan speeds or underpowered alternatives

What tool is required for securing this clamp to the shaft

What is the connection size for this model

it is recommended to mount the solenoid with the coil in an upright vertical position

Check for carbon deposits or "soot" on the electrode

Lochinvar & A.O. Smith 100208661 Flow Switch 321894-706 mismatched fan speeds or underpoweredThe Lochinvar & A. O. Smith 100208661 Flow Switch, also identified by part number 781621 or alias FS8 W, is a heavy duty liquid flow switch engineered for precise proof of flow detection in high efficiency commercial boiler systems and water heaters. Designed as a direct HVAC replacement part for the McDonnell & Miller FS8 W, this unit features a durable stainless steel #3 paddle configuration to ensure reliable contact closure once the system pump