Mcdonnell & miller for residential, commercial and industrial low or high pressure boiler applications. For boilers of any steaming capacity. Monel bellows provides corrosion resistance. Float chamber with integral water column provided snap action for high temperature service – 1 single pole, single throw switch for pump control – 1 single pole, double throw switch for low water cut-off and alarm actuation. Optional features – manual reset – integral conductance probes for additional levels and greater operating differential-model 157s-rbp-md – 1in or 1-1/4in npt equalizing tapings – 1/2in or 3/4in npt tapings for gauge glass/tri-cock installations. Bspt threads. Maximum pressure 150 psi 10. 5 kg/cm2. .