Frequently Asked Questions
What boiler control brands does Memphis Control Center stock?
We stock boiler controls from McDonnell & Miller (Series 150S, 157S, 67, 64, 63, 193, 194), Hydrolevel (CG400, HydroStat 3000, VXT series), Hoffman Specialty (steam traps, air vents, boiler accessories), and Warrick-Gems (Series 16, 26, DFC dual-function controls). Over 2,800 products with free same-day shipping from Memphis, TN.
What is a low water cutoff and why does my boiler need one?
A low water cutoff (LWCO) is a required safety device that shuts down a boiler's burner when water drops below a safe operating level, preventing overheating, boiler damage, and potential explosion. ASME, NFPA 85, and most local codes require LWCO devices on commercial and industrial steam and hot water boilers. McDonnell & Miller and Hydrolevel are the most widely specified brands.
What is the difference between the McDonnell & Miller 150S and 157S?
The McDonnell & Miller 150S is a low water cutoff only. The 157S is a combination low water cutoff and pump controller in one unit — it adds pump control functionality so a single device handles both LWCO protection and boiler feedwater pump cycling. The 157S is the most common choice when adding pump control to an existing steam boiler.
What is the difference between a float-type and electronic low water cutoff?
Float-type LWCOs (McDonnell & Miller 150S, 157S, 67) use a mechanical float assembly to sense water level — reliable and time-tested but require periodic float chamber maintenance. Electronic LWCOs (Hydrolevel CG400, HydroStat 3000) use probe-type conductance sensing with no moving parts — offering greater reliability, easier maintenance, and built-in self-diagnostics. Electronic models are increasingly specified for commercial boiler room upgrades.
Do you stock hard-to-find and legacy boiler control parts?
Yes. Memphis Control Center maintains deep inventory on both current and legacy models from all four brands. We stock replacement gaskets, floats, switches, and repair parts for McDonnell & Miller Series 63, 64, 67, 150, and 157 going back decades. Call us at (901) 458-2000 — if a part exists, we can source it.
Do you ship boiler controls same-day?
Yes. In-stock boiler controls ship same-day on orders placed by 2 PM CT with free ground shipping nationwide from Memphis, TN.
