Name: RCM Flo-Gard II Inline Flow Switches
Brand: RCM Industries
Availability: InStock

Question 1

What is the difference between the GP (general purpose) and IS (intrinsically safe) versions?

Accepted Answer

The GP (general purpose) Flo-Gard II uses standard reed switches rated at 10W, 125 Vac / 175 Vdc for use in non-hazardous environments. The IS version (Option -1S2-IS or -2S2-IS) is CSA/NRTL and ATEX/KEMA certified intrinsically safe for hazardous locations — Class I, Division 1, Groups A, B, C & D and Zone 0. The IS contact rating is reduced to Vmax = 28V, Imax = 110 mA, Pmax = 1.2W. If your installation is in a classified hazardous area, always specify Option IS.

Question 2

Should I choose 1S2 (one switch) or 2S2 (two switches)?

Accepted Answer

Choose 1S2 if you need a single setpoint — typically a low-flow alarm to protect equipment from loss of cooling or lubrication. Choose 2S2 if you need both a low-flow and a high-flow alarm simultaneously on the same meter. Both switches on a 2S2 unit are independently adjustable from 30% to 90% of full scale. Factory defaults are Switch #1 at 30% and Switch #2 at 95% of full scale.

Question 3

Can the Flo-Gard II be used on gas service?

Accepted Answer

Yes. The Flo-Gard II handles both liquids and gases. Liquid flow ranges from 4 GPH (15 l/h) in a ½″ meter up to 3,000 GPM (12,000 l/m) in an 8″ meter. Gas flow ranges from 40 SCFH (1 Nm³/h) in a ½″ meter up to 20,000 SCFM (600 Nm³/h) in an 8″ meter. Specify Option I for compressed gas service.

Question 4

What is the low-flow Option ES?

Accepted Answer

Option ES extends the Flo-Gard II down to very low liquid flow rates. In a ½″ meter, ES ranges start at just 4 GPH (15 l/h, 200 cc/min) and step up through 6, 10, 15, 20, 30, 40, 60, and 100 GPH. Contact Northeast Controls to specify an ES range for your application.

Question 5

What flow range should I select for best switch performance?

Accepted Answer

Select a range where your desired trip point falls at approximately 50% of the maximum flow range. Switches are adjustable from 30% to 90% of full scale, so avoid applications where the trip point would fall outside that window. For very low flows, specify Option ES.

Question 6

What are the electrical ratings for the GP (general purpose) contacts?

Accepted Answer

GP reed switch contacts are rated at 10 watts maximum, 125 Vac maximum, 175 Vdc maximum, 350 mA maximum switching current, 1.5 A maximum carry current. Ratings are based on resistive loads — contact the factory for switching inductive loads.

Question 7

What are the electrical ratings for the IS (intrinsically safe) contacts?

Accepted Answer

IS entity parameters: Vmax = 28V, Imax = 110 mA, Pmax = 1.2W, Ci = 0 µF, Li = 0 µH. The optional LED indicator is rated 0.50W, 24V, 20 mA. Always use with an approved intrinsic safety barrier.

Question 8

What is the maximum pressure and temperature rating?

Accepted Answer

Maximum pressure is 400 psig (28.1 kg/cm²), minimum 10 psig. Standard temperature range is -30°F to 212°F. Optional extended range is -80°F to 350°F. Body materials include Bronze and 316 Stainless Steel.

Question 9

What is the setpoint accuracy and hysteresis?

Accepted Answer

Setability is ±5% of full scale. Repeatability is ±1% of full scale. Hysteresis (difference between trip and reset points) is 7 to 13% of full scale for IS versions and 13% for GP versions. This hysteresis prevents rapid cycling near the setpoint in applications with fluctuating flow.

Question 10

How do I wire the SPDT contacts?

Accepted Answer

Each switch has three terminals: Common (C), Normally Open (N.O.), and Normally Closed (N.C.). For a low-flow alarm (circuit activates when flow drops below setpoint), wire your load between C and N.C. For a high-flow alarm (circuit activates when flow rises above setpoint), wire between C and N.O. For IS versions, terminate the cable shield inside the conduit housing but outside the meter housing, and refer to Control Drawing #6931 (no LED) or #6932 (with LED).

Question 11

What conduit and cable is recommended?

Accepted Answer

Use ½″ watertight conduit or a cable gland. Recommended cable: 20 AWG, 3 or 6 conductors with drain wire, multiconductor shielded communication cable (20 AWG 7/28). Use NEC/CEC-approved, CSA/UL/CE/OSHA-listed fittings. For IS installations, use conduit seals rated for the applicable hazardous area classification.

Question 12

How do I adjust the switch setpoint?

Accepted Answer

Remove the cover (4 × #6-32 flat head screws). Turning the adjustment screw clockwise raises the setpoint; counterclockwise lowers it. Factory settings: Switch #1 = 30% F.S., Switch #2 = 95% F.S. Use the green mark on the adjustment disc as a reference. The adjustment chart: 0 turns = 30%, ½ turn = 60%, 1 turn = 80%, 1½ turns = 90%, 2 turns = 100% of full scale.

Question 13

How do I calibrate the switch in the field?

Accepted Answer

Connect a continuity tester or multimeter to the Common and desired contact (N.O. or N.C.). Establish flow at the desired setpoint. For N.O.: turn screw clockwise to stop (light ON), then counterclockwise until light turns OFF, then continue until it just turns ON again — stop. For N.C.: turn clockwise to stop (light OFF), counterclockwise until light turns ON, then continue until it just turns OFF — stop. Both procedures set the switch to approximately 30% F.S. at the green dot (3:00 position). After calibration, replace cover and tighten all four screws.

Question 14

What are the piping installation requirements?

Accepted Answer

Observe the flow direction arrow on the body. Install in a location that remains full (closed loop system). Provide at least 10 pipe diameters of straight pipe upstream between the meter inlet and any fittings such as elbows, tees, or valves. The unit can be mounted in any orientation.

Question 15

What hazardous location approvals does the Flo-Gard II carry?

Accepted Answer

CSA/NRTL/c: AEx ia IIC — Class I, Division 1, Groups A, B, C, D; Class II, Division 1, Groups E, F, G. KEMA: Ex ia IIC — Zone 0, II 1G T4, 0°C ≤ Ta ≤ 50°C. ATEX: EC Type Examination Certificate. CE marked.

Question 16

Can I modify the unit for use in a hazardous location?

Accepted Answer

No. Modifications not described in the installation instructions are not permitted and may create explosion hazards. Only qualified service personnel aware of the hazards should perform external wiring. The product must be used with an approved intrinsic safety barrier as part of a complete IS system.

Specification	Standard	Optional
Maximum Pressure	400 psig (28.1 kg/cm²)	—
Minimum Pressure	10 psig	—
Maximum Temperature	212°F (100°C)	350°F (177°C)
Minimum Temperature	-30°F (-34°C)	-80°F (-62°C)
Housing	Aluminum	—
Body	Bronze	316 Stainless Steel
Bellows	Bronze	316 Stainless Steel
Seals	Buna-N	Viton, EPR, Teflon
Setability	±5% F.S.	—
Repeatability	±1% F.S.	—
Hysteresis	13% F.S. (GP) / 7–13% F.S. (IS)	—
GP Contact Rating	10W max, 125 Vac / 175 Vdc, 350 mA switching, 1.5 A carry	—
IS Entity Parameters	Vmax=28V, Imax=110mA, Pmax=1.2W, Ci=0µF, Li=0µH	—
LED Rating (Option LED)	0.50W, 24V, 20mA	—
Liquid Flow Range	4 GPH (½″) to 3,000 GPM (8″)	—
Gas Flow Range	40 SCFH (½″) to 20,000 SCFM (8″)	—

Code	Description
A	Viton Seals
B	EPR Seals
B2	Teflon Seals
ES	Low Flow Rate (below 2 GPM)
I	Compressed Gas Service
1S2	1 Single Pole Double Throw Switch
2S2	2 Single Pole Double Throw Switches
-IS	Intrinsic Safe Approval (CSA / ATEX / KEMA)
-LED	Light Emitting Diode Indicator

RCM Flo-Gard II Flow Switches

Standard Features

Typical Applications

Specifications

Model Number System

Option Codes

Hazardous Location Approvals (Option IS)

Setpoint Adjustment Chart

Low Flow Rates — Option ES (½″ Meter)

Flow Switch FAQ

Selection & Application

Specifications & Ratings

Installation & Wiring

Hazardous Locations

Select a Product

GPH	l/h	cc/min
4	15	200
6	20	300
10	40	400
15	60	600
20	80	1,000
30	120	2,000
40	150	3,000
60	240	4,000
100	400	6,000

Screw Turns	% Full Scale
0 (factory)	30%
½	60%
1	80%
1½	90%
2	100%