whereas they can serve as either primary or secondary on hot water boilers

it is highly recommended to install the valve with the coil facing upward to prevent sediment buildup in the armature tube

and large commercial boiler systems

Can I use this blower wheel for other Aaon models

This is a standard 24 VAC control valve

McDonnell & Miller 157S Controller R-410A whereas they can serve asThe McDonnell & Miller 157S is a heavy duty combination low water cut off and pump controller engineered for commercial and industrial steam and hot water boilers. This specific OEM part #173502 features the 157S series head mechanism (part #173003) equipped with a snap acting SPDT switch. Designed for high pressure applications up to 150 psi (10. 5 kg cm), this controller ensures precise liquid level management, acting as a critical failsafe by