Product Overview

BOILER WATER LEVEL CONTROL
Heavy Duty, Cast Iron Chamber
The Series 123 & 125 Boiler Water Level Control is designed for boiler applications,
the Model 123 is primarily used for low water cut-off or feed-water control. The 125
offers the same long lasting service with a direct action mercury switch movement that
provides a close deadband where needed.
FEATURES/BENEFITS
• Special snap action switch mechanism options eliminates frequent operation due to
surging water level
• Transparent cover provides convenient visible operation of the switch
• Flangedchamberforeasycleanoutandreplacementofoatorswitchmechanism
without removing the unit from piping
APPLICATIONS
• Boiler low water cut-off
• Boiler feed-water control
• Condensate tanks
• Deaerators
5-1/2
[139.70]
7
[177.80]
Ø5-3/4
[146.05]
5-3/8
[136.53]
1/2 PIPE PLUG
TYP 2 PLACES
4-3/4
[120.65]
3-9/16
[90.50]
1 NPT
7-1/8
[180.98]
2-7/16
[61.91]
3-9/16
[90.50]
1-1/8
[28.58]
SPECIFICATIONS
Service: Compatible liquids. Cast iron
isnotforusewithlethalorammable
substances either liquid or gaseous.
Wetted Materials: Body: Cast iron;
Float: 304 SS; Trim and packing gland:
Brass; Packing: Carbon; Body gasket:
Carbon.
Temperature Limit: Ambient
temperature: 212°F (100°C);
Process temperature: 365°F (185°C).
Pressure Limit: 150 psig (10.34 bar).
Enclosure Rating: General purpose.
Optional weatherproof.
Switch Type: SPDT snap switch or
mercury switch. Optional DPDT or two
stage.
Electrical Rating: Snap switch: 12 A
@ 120 VAC, 5 A @ 240 VAC, 0.5 A @
125 VDC resistive, 0.25 A @ 250 VDC
resistive; Mercury switch: 4 A @ 120
VAC/DC, 2 A @ 240 VAC/DC.
Electrical Connections: Screw terminal.
Conduit Connection:7/8˝(22.23mm)
holefor1/2˝(12.7mm)conduit.
Process Connections:1˝femaleNPT.
Mounting Orientation: Vertical.
Deadband:Approximately1-1/2˝
(38.1 mm).
Specic Gravity: 0.88 min.
Options: Manual reset.
Weight: 20 lb (9.1 kg).
Agency Approvals: CSA, UL. (Snap
switch is not rated).
DWYERINSTRUMENTS,INC.|dwyer-inst.com318
Level Switches,
Float
LEVEL
FLANGED CHAMBER TYPE LEVEL CONTROL
Operating Pressures to 300 PSIG
The Series 102 & 1102 Flanged Chamber Type Level Control is external cage
type level switches which are self-contained in a side mount body. The 102 series
willoperatetoaminimumspecicgravityof0.60andthe1102serieswilloperatetoa
specicgravityof0.40.Theseseriescontainastainlesssteeloatandofferachoice
ofcastiron,caststeel,orcast316SSoatchamber.
FEATURES/BENEFITS
• Unique design allows the simple removal of four bolts from the inspection plate to
 examinetheoatandchamberforcleaningorwearwithoutdisconnectingthepiping
or electrical circuitry
• Electrical enclosures provide general purpose, weatherproof, explosion-proof
 orexplosion-proof/vaporproofcapabilityaswellascosteffectivecast316SSoat
chamber option
• Electrical circuits using hermetically sealed snap action or mercury contacts are
available in a variety of actions including SPST, SPDT, DPDT and DPST combinations
• The102designfeaturesthree1˝NPTprocessconnectionsforside/sideorside/
 bottompipingallowingthebottom1˝NPTconnectiontobeusedasadrainwhen
using the side/side process connection
APPLICATIONS
• Pressure or vacuum vessels
• Chemical processing plants
• Steam and electric generating stations
• Hydraulic accumulators
• Vapor-liquid separators
• Scrubbers
• Oilreneries
• Storage tanks
Ø5-3/4
[146.05]
6-1/8
[155.58]
A
B
6-3/4
[171.45]
17-1/2
[444.5
]
3/4 NPT CONDUIT
CONNECTION. CAN
BE ROTATED 360˚.
1 NPT
8-1/4
[209.55]
4-7/8
[123.83]
3-1/4
[82.55]
1-5/8
[41.28]
SPECIFICATIONS
Service: Compatible liquids. Cast iron
isnotforusewithlethalorammable
substances either liquid or gaseous.
Wetted Materials: Body: Cast iron.
Optional cast steel or 316 SS; Float and
trim: 303 SS, 304 SS, 316 SS, and 430
SS. Option of all 316 SS; Body gasket:
Carbon.
Temperature Limit: Ambient
Temperature: 212°F (100°C); Process
Temperature: 425°F (218°C).
Pressure Limit: 300 psig (20.7 bar).
Optional rating to 400 psig (27.6 bar).
Enclosure Rating:NEMA4X(IP66).
Optional general purpose or explosion-
proof.
Repeatability:±1/4˝(6.4mm).
Switch Type: SPDT snap switch,
hermetically sealed snap switch, or
mercury switch. Optional DPDT or two
stage.
Electrical Rating: Snap switch: 12 A
@ 120 VAC, 5 A @ 240 VAC, 0.5 A @
125 VDC resistive, 0.25 A @ 250 VDC
resistive; Hermetically sealed snap
switch: 5 A @ 125 VAC, 5 A @ 240 VAC,
5 A @ 30 VDC resistive; Mercury switch:
4 A @ 120 VAC/DC, 2 A @ 240 VAC/DC.
Higher contact ratings available for the
mercury switch.
Electrical Connections: Screw terminal.
Conduit Connection:3/4˝femaleNPT.
Process Connections:1˝femaleNPT.
Mounting Orientation: Vertical.
Set Point Adjustment:±1˝(25.4mm).
Specic Gravity: 0.6 min.
Weight: 35 lb (15.9 kg).
Agency Approvals: UL.
Specic Gravity A B
1.0
0.6
5-1/16 [129 mm]
5-13/16 [148 mm]
3/4 [19 mm]
1 [25.4 mm]
SERIES 123 & 125 | MERCOID
®
BY DWYER
SERIES 102 & 1102 | MERCOID
®
BY DWYER
USA: California Proposition 65
WARNING:CancerandReproductiveHarm-www.P65Warnings.ca.gov
MODEL CHART
Model Switch Type
123-153
123-7000-153
SPDT mercury
SPDT snap
MODEL CHART
Model Switch Type
102-WT-4810-C-60
102-WT-7810-C-60
102-WT-7810HM-C-60
SPDT mercury
SPDT snap
SPDT hermetically sealed snap
Level_2021.indb 318 7/15/20 10:49 AM