R851B/V Line Voltage Step/Vernier Controller

The R851B/V series line voltage ( up to 240 V a.c.) electronic step controller is designed for cost-effective and precise control of multi-stage applications typically found in electric duct heaters and boilers. Available in four or eight stage models, the R851V can also be used in conjunction with the R810 power switch or R820 SCR power controller, which will result in a fully proportional control of the load. The R851B is specifically designed for electric boiler sequencing. The R850 can also be used on any type of staging applications found in refrigeration or automation applications.

Features:

	Microcomputer-based
	Adjustable inter-stage time delay
	Test-button to bypass time delay
	Choice of last-in first out (LIFO) or first in, first out (FIFO) configuration for even wear
	8 stage model can be slaved to another 8 or 4 stage R850 for 12 or 16 stages maximum
	Accepts industry standard signals: 0-10 V d.c., 4-20 ma d.c., 0-135 ohm