Compact, Low Cost, Hermetically Sealed Snap Switch Option

Heavy duty and low cost is the perfect description for the 391 Series level control. Stainless steel switching mechanism uses gravity return action instead of springs for long life. Weatherproof enclosure is standard. Welded steel chamber is good for 650 psig (45 bar) at 600°F (315°C).

Product Applications

Refineries
Chemical plants
Power generating stations
Water treatment plants
Mixing systems
Scrubbers
Accumulators
Condensate recovery
Industrial tanks and vessels

More Information

Model Chart

EXAMPLE	391	WT	7810	C1	70		391-WT-7810-C1-70 Liquid Level Control with welded carbon steel chamber, watertight – NEMA 4X enclosure, SPDT snap action switch rated 12 amp 120 VAC, 5 amp 240 VAC, fixed deadband and automatic reset, operating pressure 600 psig (41 bar) at 100ºF (38ºC), 500 psi (34 bar) at 600ºF (315ºC), side/bottom process connections 1” NPT, minimum specific gravity 0.70.
CONNECTION	391						One Horizontal and One Vertical 1” NPT or Socket Weld
	393						One Vertical and One Horizontal Flanged Connection
	394						Two Vertical Flanged Connections
ENCLOSURE		G					General purpose, NEMA 1
		WT					Weatherproof, NEMA 3R, 4, 4X
		E					Explosion-proof, NEMA 7, 9, Class I Groups B, C, D, Class II Groups E, F, G
		EV					Explosion-proof, vapor proof, NEMA 7, 9, Class I Groups B, C, D, Class II Groups E, F, G
CIRCUITS (for electrical circuits, See charts A & B below)			48XX				Single stage, mercury switch, see chart A.
			48XX				Two stage, mercury switch, see chart A.
			78XX				Single stage, snap switch, see chart B.
			78XX				Two stage, snap switch, see chart B.
			78XXHM				Hermetically sealed snap switch, see chart B.
			98XX				Single stage, high capacity DC snap switch, see chart B.
			98XX				Two stage, high capacity DC snap switch, see chart B.
			10XX				Single stage, high temperature snap switch, see chart B.
			10XX				Two stage, high temperature snap switch, see chart B.
CHAMBER MATERIAL							Refer to chart C below for pressure/temperature ratings
CHAMBER MATERIAL				C1			Carbon steel body
MINIMUM SPECIFIC GRAVITY					70		0.70 specific gravity (391 only)
					80		0.80 specific gravity (391 only)
					95		0.95 specific gravity (391 only)
					170		0.70 specific gravity & 150# flange (393, 394 only)
					180		0.80 specific gravity & 150# flange (393, 394 only)
					195		0.95 specific gravity & 150# flange (393, 394 only)
					370		0.70 specific gravity & 300# flange (393, 394 only)
					380		0.80 specific gravity & 300# flange (393, 394 only)
					395		0.95 specific gravity & 300# flange (393, 394 only)
					670		0.70 specific gravity & 600# flange (393, 394 only)
					680		0.80 specific gravity & 600# flange (393, 394 only)
					695		0.95 specific gravity & 600# flange (393, 394 only)
OPTIONS						H2	1” socket weld hub instead of 1” NPT
						STW	SS tag wired
						01	Breather only (E-Housing only)
						02	Drain only (E-Housing only)
						12	Breather and drain (E-Housing only)
						23720	Fungus proofing special 23720

CHARTS A & B - ELECTRICAL CIRCUITS AND RATINGS

SWITCH TYPE	SWITCH ACTION	ELECTRICAL RATINGS IN AMPS						ORDERING CODE
		AC			DC			SINGLE STAGE	TWO STAGE
		120V	240V	440V	30V	125V	250V	SINGLE STAGE	LOWER	UPPER
CHART A Mercury Contacts	SP-ST open on level FALL	10	5	3†		10	5	-4821	-4821	-21	UL
	SP-ST open on level RISE	10	5	3†		10	5	-4820	-4820	-20	UL
	SP-DT one switch	4	2	1†		4	2	-4810	-4810	-10	UL
	SP-DT two switches E.I.*	10	5	3†		10	5	-4815	-4815	-15	UL
	DP-ST two switches E.I.* open on level FALL	10	5	3†		10	5	-4813	-4813	-13	UL
	DP-ST two switches E.I.* open on level RISE	10	5	3†		10	5	-4814	-4814	-14	UL
	DP-DT two SP-DT switches	4	2	1†		4	2	-4806	-4806	-06	UL
CHART B snap action contacts	SP-DT one switch	12	5	3†		0.5**	0.25**	-7810	-7810	-10	UL
	DP-DT Two SP-DT switches	12	5	3†		0.5**	0.25**	-7806	-7806	-06	UL
	SP-DT one hermetically sealed switch	5	5		5**			-7810HM	-7810HM	-10HM
	DP-DT two hermetically sealed SP-DT switches	5	5		5**			-7806HM	-7806HM	-06HM
	DP-DT two SP-DT switches	10	3			10‡	3‡	-9806	-9806	-06
	SP-DT one switch	10	3			10‡	3‡	-9810	-9810	-10
	DP-DT two SP-DT switches	2	2			0.4**	0.25**	-1006	-1006	-06
	SP-DT one switch	2	2			0.4**	0.25**	-1010	-1010	-10

Specifications

Service:Compatible liquids.
Wetted Materials:Body: carbon steel; Float and Trim: 303 SS, 304 SS, 316 SS, and 430 SS.
Temperature Limits:Process: 600°F (315.6°C). Heat fins should be used for process temperatures above 500°F (260°C) with mercury switches, 400°F (204°C) with snap switches, and 350°F (176.7°C) with hermetically sealed snap switches.
Pressure Limits:800 psig (55 bar) at 100°F (37.7°C), 650 psig (45 bar) at 600°F (315.6°C). Higher ratings available.
Enclosure Rating:NEMA 4X. Optional general purpose or explosion-proof.
Switch Type:SPDT snap switch, hermetically sealed snap switch or mercury switch. Optional DPDT.
Electrical Rating:Snap Switch: 12A @ 120 VAC, 5A @ 240 VAC, 0.5A @ 125 VDC resistive, 0.25A @ 250 VDC resistive. Hermetically Sealed Snap Switch: 5A @ 125 VAC, 5A @ 240 VAC, 5A @ 30 VDC resistive. Mercury Switch: 4A @ 120 VAC/DC, 2A @ 240 VAC/DC. Higher contact ratings available for the mercury switch.
Electrical Connections:Screw terminal.
Conduit Connection:3/4" female NPT.
Connections:1" female NPT. Optional 1" socket weld hub or flange connections.
Mounting Orientation:Vertical.
Weight:10 lb (4.5 kg).
Agency Approvals:UL, none on HM switch.
Specific Gravity:0.8 minimum. Optional 0.7 minimum.

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Series 391/393/394 Side Mounted-Chamber Type Level Control

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