Question 1

How does a Flo-Gage™ flow meter measure flow rate?

Accepted Answer

Flo-Gage™ threaded and wafer style flow meters measure flow rate by sensing the pressure differential created across a flow nozzle machined directly into the body of the meter. A pair of matched, opposed bellows sense the differential pressure and drive a mechanical linkage to indicate flow rate directly on the dial. When fitted with a blind transmitter or digital display readout, the bellows and mechanical linkage are replaced with a solid-state differential pressure sensor.

Question 2

What is the difference between a mechanical dial meter and a digital/transmitter model?

Accepted Answer

Mechanical dial meters use matched opposed bellows and a mechanical linkage to drive the pointer. Digital or transmitter-equipped models replace the bellows and linkage with a solid-state differential pressure sensor, providing an electronic output signal.

Question 3

How much straight pipe is required upstream of the flow meter?

Accepted Answer

Provide at least 10 pipe diameters of straight pipe upstream between the flow meter inlet and any upstream fitting such as elbows, tees, or valves. No special downstream straight-pipe requirements exist. Note: Flow meters are calibrated using Schedule 40 pipe connections. Tubing and hoses do not have the same I.D. as pipe — transition to pipe at least 10 pipe diameters upstream for rated accuracy.

Question 4

What site conditions should I avoid when installing the meter?

Accepted Answer

Avoid locations subject to water hammer, excessive vibration, or shock loading. For outdoor or splash-exposure installations, use a gasketed case. Protect the meter from freezing liquids.

Question 5

How do I change the dial orientation in the field?

Accepted Answer

1. Observe the flow direction arrows on the meter body. 2. Remove the four screws holding the body to the housing. 3. Do NOT remove the two screws holding the housing to the cell block assembly. 4. Rotate the housing to the desired 90° position. 5. Reinstall the screws carefully without pinching the O-rings. Re-zero the flow meter after any orientation change.

Question 6

How do I change the meter from horizontal to vertical mounting?

Accepted Answer

Standard design: Remove the lens by rotating counter-clockwise. Do NOT remove the pointer. Gently pry the dial forward, rotate it to the desired viewing position, then push the dial back into the locating indents. Alternate design: Remove the retaining ring and crystal, remove the two dial screws, rotate the dial, then reinstall the screws. Note — screws may require shortening to approximately 1/8" (3 mm) to prevent interference with gear movement. Always re-zero the flow meter after adjustment.

Question 7

How do I install a threaded body flow meter?

Accepted Answer

Use a suitable thread sealant and ensure threads are clean and burr-free before installation.

Question 8

How do I install a wafer style flow meter?

Accepted Answer

Install the meter between mating flanges. Important: Center gaskets carefully so they do NOT protrude into the flow stream. Improper gasket placement causes significant measurement error.

Question 9

What are the pressure and temperature limits I must not exceed?

Accepted Answer

Do not exceed the pressure or temperature limits marked on the nameplate. Although each meter is pressure tested to 150% of rated pressure, overpressure may cause injury, meter damage, or leakage. Temperature ratings are based on the mechanical linkage, elastomer seals, and any fitted electronics. Contact the factory for high-temperature applications.

Question 10

Does the flow meter require routine lubrication?

Accepted Answer

No routine lubrication is required. Keep the interior clean and free of dust, moisture, oil, and corrosives. Protect from solvents and corrosive splashing.

Question 11

How do I check and adjust the zero on my flow meter?

Accepted Answer

1. Stop flow completely. 2. Remove the lens. 3. Observe the pointer position — it should align with the zero reference point. If the pointer is within 1/2" of zero, perform a Fine Zero Adjustment. If the pointer is more than 1/2" from zero, perform a Coarse Zero Adjustment. Note: Water hammer or pressure surges are common causes of zero shift.

Question 12

How do I perform a Coarse Zero Adjustment?

Accepted Answer

1. Place a screwdriver in the slotted pointer hub. 2. Rotate the hub approximately 1/4 turn clockwise relative to the pointer. 3. Verify the pointer preload. 4. Adjust the cam nut until the pointer aligns with the zero reference point. Important: The stop nut must stop center shaft movement before the bellows contact the cell cap. Failure to observe this may damage the bellows, cause leakage, or cause meter error.

Question 13

How do I perform a Fine Zero Adjustment?

Accepted Answer

Do NOT use the fine zero adjustment if the meter contains a 4-wire transmitter or reed switches — use the coarse adjustment instead. 1. Rotate the pointer hub relative to the pointer. 2. Align the pointer with the zero reference point. 3. Tap the housing gently to overcome friction. 4. Verify the pointer returns smoothly to zero.

Question 14

How do I verify and adjust flow calibration in the field?

Accepted Answer

1. Verify zero adjustment first. 2. Cycle flow from zero to full scale 3–4 times — the pointer should return smoothly to zero each time. Calibration adjustment: At approximately 90% full-scale flow, move the cam follower UP to decrease indication or DOWN to increase indication. Accuracy: The meter should indicate within ±3% of full scale. NIST traceable certifications and factory recalibration are available.

Question 15

How do I clean the pressure ports?

Accepted Answer

1. Remove the housing from the body. 2. Remove the pulsation snubbers. 3. Clean the body passages and snubbers. 4. Reassemble carefully. If complete cleaning is not possible in the field, return the unit to the factory.

Question 16

How do I adjust the reed switch setpoint?

Accepted Answer

1. Verify zero adjustment first. 2. Connect a continuity tester to the N.O. (normally open) contact. 3. Loosen the switch clamp. 4. Establish the desired flow setpoint. 5. Slide the switch while monitoring the contact. Adjustment direction: Slide RIGHT for a higher setpoint, LEFT for a lower setpoint. Tiny adjustments may be required.

Question 17

How do I check the pointer preload?

Accepted Answer

Rotate the pointer counter-clockwise (CCW) toward full scale. Proper preload: The pointer stops at full scale. If the pointer exceeds full scale, adjust using the cam nut.

Question 18

My meter pointer is fluctuating — what should I check?

Accepted Answer

Pointer fluctuation is usually caused by turbulence from nearby valves or fittings. Solutions: • Increase the straight pipe length upstream (minimum 10 pipe diameters). • Install heavy-duty pulsation snubbers.

Question 19

My meter zero has shifted — what causes this and how do I fix it?

Accepted Answer

Zero shift is usually caused by excessive water hammer. Fix: Modify piping or operating procedures to reduce shock loading. Then re-zero the meter using the Coarse or Fine Zero Adjustment procedure.

Question 20

My meter response is sluggish — what are the possible causes?

Accepted Answer

Sluggish meter response is typically caused by: • Inadequate spring preload • Plugged pressure passages Solution: Clean the pressure ports and verify the pointer preload.

Question 21

My meter is reading inaccurately — what should I check first?

Accepted Answer

1. Verify zero adjustment with flow stopped. 2. Check that at least 10 pipe diameters of straight pipe exist upstream. 3. Confirm the meter is calibrated for the actual fluid (check specific gravity for liquids, or pressure/temperature for gases). 4. Check for plugged pressure ports or pulsation snubbers. 5. Verify gaskets are not protruding into the flow stream (wafer style). If inaccuracy persists, contact Northeast Controls for factory recalibration.

Question 22

What signal does the digital display require?

Accepted Answer

The digital display (Option R built-in, or DR-1 remote) requires a 4–20 mA DC signal from transmitter options W2 or W3.

Question 23

What are the terminal designations for the remote DR-1 display?

Accepted Answer

Terminal 1 — Return (−) Terminal 2 — Supply (+) Terminal 3 — Totalizer Reset Terminal 4 — Reset Common Terminal 5 — Pulse Output (−) Terminal 6 — Pulse Output (+) Install a jumper to enable front panel lockout. After battery replacement, momentarily jumper with loop power applied to initialize.

Question 24

What are the pulse output specifications for the digital display?

Accepted Answer

Output type: Open collector Maximum frequency: 25 Hz Pulse width: 15 ms To set a desired voltage peak, use the formula:   R2 = Desired Vpeak × 10,000 / Vpower supply   R1 = 10,000 − R2 Example: Desired Vpeak = 5V, Supply = 24Vdc → R2 = 2,000 Ω, R1 = 8,000 Ω Caution: Observe proper polarity. Damage may result from reverse polarity or voltages over 30V.

Question 25

What does adjusting the SPAN POT do?

Accepted Answer

Adjusting the SPAN POT changes the meter calibration. Use caution — only adjust if recalibration is required.

Question 26

How do I clear the totalizer on the digital display?

Accepted Answer

Press the CLEAR button twice to reset the total. Note: The accumulated total cannot be reset and has a maximum of 99,999,999,999.

Question 27

What does the "LOW BATTERY" warning mean and what should I do?

Accepted Answer

When the battery becomes low, "LOW BATTERY" flashes on the display. Replace the battery shortly after the warning appears. Use only manufacturer-approved batteries.

Question 28

What programming functions are available on the digital display?

Accepted Answer

Enter Code (ent code) — displayed only if panel lock is ON; enter correct code to advance, incorrect code returns to run mode. Clear Total (clr tot) — press E to clear, press M to skip. 3 or 4 Digit Display — select 3.5 or 4.5 digit display. Decimal Location (dec loc) — sets decimal for rate display, rate high, and rate low. Totalizer Decimal (tdec) — sets decimal for totalizer (e.g. 1234567.8).

Question 29

Which reed switch options are covered by the intrinsically safe manual?

Accepted Answer

The Series 7000 & 8000 IS manual covers four option codes:   • -1S2-IS-LED — Single SPDT reed switch with LED indicator   • -1S2-IS — Single SPDT reed switch (no LED)   • -2S2-IS-LED — Dual SPDT reed switches with LED indicators   • -2S2-IS — Dual SPDT reed switches (no LED) Certifications: CSA (Canada), KEMA/ATEX (Europe). Applicable standards: EN 60079-0:2009, EN 60079-11:2007, EN 60079-26:2007. Hazardous location rating: ATEX II 1 G Ex ia IIC T4 Zone 0 | Class I Groups A, B, C, D | Class II Groups E, F, G.

Question 30

What are the entity parameters for the IS reed switches?

Accepted Answer

Vmax: 28 V Imax: 110 mA Pmax: 1.2 W Ci: 0 µF Li: 0 µH

Question 31

What are the general purpose contact ratings for the IS reed switches?

Accepted Answer

Contact Power: 10 W max Voltage (AC): 125 Vac max Voltage (DC): 175 Vdc max Switching Current: 0.35 A max Carry Current: 1.5 A max Hysteresis: 13% FS LED Ratings: 24 Vdc, 20 mA, 0.50 W metal film resistor

Question 32

What cable is recommended for IS reed switch wiring?

Accepted Answer

Use NEC/CEC approved cable. Recommended: 20 AWG, 3 or 6 conductor shielded communication cable (20 AWG 7/28). Use CSA certified watertight conduit or cable gland. Recommended: Liquid-tight strain relief connector. Terminate shield inside the outer housing, outside the inner shield housing.

Question 33

How do I wire the -1S2-IS-LED or -2S2-IS-LED options (with LED)?

Accepted Answer

A 24 Vdc power supply is required (Option PS-24). Switch #1 wiring:   Terminal 1 — +24 Vdc power   Terminal 2 — NC (Normally Closed) — connect 24 Vdc (−) for Low Normally Closed   Terminal 3 — NO (Normally Open) — connect 24 Vdc (−) for Low Normally Open Switch #2 wiring (-2S2-IS-LED):   Terminal 4 — NC — connect 24 Vdc (−) for High Normally Open   Terminal 5 — NO — connect 24 Vdc (−) for High Normally Closed

Question 34

How do I wire the -1S2-IS or -2S2-IS options (without LED)?

Accepted Answer

Switch #1 wiring:   Terminal 1 — NC (Normally Closed)   Terminal 2 — COM (Common)   Terminal 3 — NO (Normally Open) Switch #2 wiring (-2S2-IS):   Terminal 4 — NC (Normally Closed)   Terminal 5 — COM (Common)   Terminal 6 — NO (Normally Open)

Question 35

How do I set the reed switch setpoint on IS models with LEDs?

Accepted Answer

1. Verify mechanical zero. 2. Remove the back cover plate. 3. Loosen the adjustment clamp screws. 4. Use the LEDs to verify switch continuity. 5. Move the lever to the desired setpoint. 6. Slide the reed switch until the LED changes state. 7. Verify switching occurs at the desired flow. 8. Tighten clamp screws carefully. 9. Replace the back cover. Setpoint adjustment direction (viewed from rear): Slide RIGHT for upscale (higher setpoint), LEFT for downscale (lower setpoint). Adjustable range: 30% to 90% of full scale. CAUTION: Do NOT flex the lever forward or backward — this will distort setpoint calibration.

Question 36

How do I set the reed switch setpoint on IS models without LEDs?

Accepted Answer

1. Verify mechanical zero. 2. Remove the back cover plate. 3. Loosen the clamp screws. 4. Connect a buzzer or continuity tester to the switch terminals. 5. Move the lever to the desired setpoint. 6. Slide the switch until the buzzer changes state. 7. Verify operation at the desired flow. 8. Tighten clamp screws carefully. 9. Replace the cover plate. CAUTION: Do NOT flex the lever forward or backward — this will distort setpoint calibration.

Question 37

What does "intrinsically safe" mean and what are the installation requirements?

Accepted Answer

Intrinsically safe means the circuits cannot generate sparks or thermal ignition sources when properly installed. IMPORTANT: Intrinsically safe does NOT mean explosion proof. Improper installation can result in fire, explosion, or serious injury. Installation references: NEC Article 504, ANSI/ISA RP12.6. Install per approved control drawings and manufacturer instructions. An IS system consists of: IS equipment in the hazardous area + an intrinsic safety barrier in the non-hazardous area + control equipment in the control room. Only qualified personnel should install or wire this equipment. Avoid impact hazards to the enclosure in Zone 0 installations.

Question 38

What safety warnings apply to IS reed switch installations?

Accepted Answer

WARNING: Failure to follow installation instructions may result in serious injury or death. WARNING: Potential spark hazard — impacts to the enclosure must be avoided in Zone 0 hazardous areas. Install per the M1 Installation, Operation & Maintenance Manual. Protect from: freezing, water hammer, pressure surges, and vibration. Do not exceed the pressure or temperature limits marked on the nameplate.

Question 39

What are the transmitter options W, X, Y, and Z?

Accepted Answer

Option W — 4–20 mA DC output Option X — Set point switching (HI and LO limit switches) Option Y — 0–1000 Hz frequency output Option Z — Combines W, X, and Y (all three outputs) All options require an external isolated 24 Vdc power supply (minimum 100 mA rated capacity). IMPORTANT: The power supply MUST be isolated — power supply ground and input signal grounds must NOT be common. Using a non-isolated supply may damage the power supply and transmitter board. IMPORTANT: Do NOT connect Terminal 7 and Terminal 9 together — damage will result.

Question 40

What is the terminal strip layout for Options W, X, Y, Z?

Accepted Answer

Terminal 1–2 — HI switch (Option X/Z) Terminal 3–4 — LO switch (Option X/Z) Terminal 5–6 — Frequency output (Option Y/Z) Terminal 7–8 — 24 Vdc input (7 = negative, 8 = positive) Terminal 9–10 — 4–20 mA output (9 = negative, 10 = positive) Wiring must be 4-wire: one pair supplies 24 Vdc to terminals 7 and 8; one pair carries the 4–20 mA signal. IMPORTANT: Do NOT connect Terminal 6 and Terminal 7 together — damage will result.

Question 41

What is the difference between W2 and W3 transmitters?

Accepted Answer

W2 — 4–20 mA output with mechanical analog indicator (local dial display retained). W3 — 4–20 mA output only; no local analog indication (blind transmitter). Both use a piezoresistive wet/wet differential pressure sensor. Both are 2-wire loop powered: 15–28 Vdc, 25 mA minimum.

Question 42

What is the 4–20 mA output calibration formula?

Accepted Answer

Formula: I = 16Q² + 4.00 Where:   I = output current in mA   Q = decimal fraction of full scale flow (e.g. 0.50 for 50% FS) Reference values:   20% FS → 4.64 mA   30% FS → 5.44 mA  (VR1 calibration point: 8.8 mA ±0.2 mA)   50% FS → 8.00 mA   75% FS → 13.00 mA   95% FS → 19.24 mA  (VR3 span calibration point: 19.2 mA ±0.2 mA)   100% FS → 20.00 mA

Question 43

What are the adjustment pot locations and functions?

Accepted Answer

VR1 — Zero (linearity) VR2 — Offset / 4 mA set point VR3 — Span VR4 — HI switch set point VR5 — LO switch set point VR6 — Frequency span Access pots by removing the rear cover plate, bezel ring, and dial crystal. Complete all mechanical adjustments before applying power. WARNING: Do NOT apply power until all connections are made.

Question 44

How do I field-calibrate the 4–20 mA output (full procedure)?

Accepted Answer

Required equipment: Digital multimeter (Fluke 9600A or equivalent), non-metallic screwdriver. Setup:   1. Remove rear cover plate, bezel ring, and dial crystal.   2. Complete all mechanical zero adjustments first.   3. Connect +24 Vdc to Terminal 8, −24 Vdc to Terminal 7.   4. Connect multimeter to Terminals 10 (+) and 9 (−). Calibration steps:   Step 1: Adjust VR1 fully counter-clockwise.   Step 2: Adjust VR2 until output reads 4.00 mA (zero/no-flow).   Step 3: Set pointer to 30% FS. Adjust VR1 to 8.8 mA ±0.2 mA.   Step 4: Set pointer to 95% FS. Adjust VR3 to 19.2 mA ±0.2 mA.   Step 5: Repeat zero and span adjustments until both are within specification. ALL grounds must be isolated: 24 Vdc input, 4–20 mA output, and frequency output.

Question 45

How does the frequency output (Option Y/Z) work and how do I calibrate it?

Accepted Answer

Factory set to 1000 Hz at full scale flow. Output characteristics: Square wave, 5Vp amplitude, 270 µs ±30 µs pulse width, 10 kΩ minimum load impedance. Frequency output drops to 0 Hz below approximately 20% of full scale. K-Factor formula: K = (1000 pulses/sec × 60 sec/min) / Full Scale Flow Rate (units/min) Example K-factors: Scale 10 → K = 6000 | Scale 100 → K = 600 | Scale 1000 → K = 60 Field calibration: If current output is also fitted, calibrate current output first. At 95% full scale, adjust VR6 for 950 Hz ±30 Hz. IMPORTANT: If current output is NOT fitted, the meter MUST be returned to the factory for frequency calibration. IMPORTANT: Do NOT connect Terminal 6 and Terminal 7 together — damage will result.

Question 46

How do the HI and LO limit switches work on Option X/Z?

Accepted Answer

LO Switch (terminals 3–4): CLOSED at zero flow; OPENS when flow reaches the set point. HI Switch (terminals 1–2): OPEN at zero flow; CLOSES when flow reaches the set point. Factory set point: 95% of full scale. Without power applied, both switches remain OPEN. Note: HI and LO naming is arbitrary — switches may be wired for desired fail-safe logic. Switch output ratings: DC — 3A @ 24 Vdc | AC — 1A @ 117 Vac | AC — 0.5A @ 230 Vac To adjust set points in the field, use VR4 (HI) and VR5 (LO) pots, or see the reed switch setpoint adjustment procedure.

Question 47

What are the W2/W3 transmitter performance specifications?

Accepted Answer

Accuracy: ±0.25% FS Response Time: 1 ms Max Static Pressure: 20 MPa Operating Temperature: −40°C to 120°C Power: 15–28 Vdc, 2-wire loop powered, 25 mA minimum

Question 48

How do I correct the meter reading for a liquid with a different specific gravity?

Accepted Answer

Use the formula: Actual Flow Rate = J × Meter Reading Where J = √(Sc / Sa)   Sc = calibrated specific gravity   Sa = actual specific gravity Example: Meter calibrated for water (SG = 1.0) reads 12.5 GPM for oil with SG = 0.85. J = √(1.0 / 0.85) = 1.085 Actual flow = 1.085 × 12.5 = 13.56 GPM

Question 49

How do I correct the meter reading for compressed gas at different pressure or temperature?

Accepted Answer

Use the formula: Actual Flow Rate = K × Meter Reading Where K = √((Pa / Pc) × (Tc / Ta))   Pa = actual pressure (psia)   Pc = calibrated pressure (psia)   Ta = actual temperature (°R = °F + 460)   Tc = calibrated temperature (°R) Example: Meter calibrated at 100°F and 80 psig reads 100 SCFM. Actual conditions: 70°F and 85 psig. K = √((99.7 / 94.7) × (560 / 530)) ≈ 1.05 Actual flow ≈ 105 SCFM Note: Use our Flow Rate Calculator at /tools/flow-calculator for automated corrections.

Question 50

Where can I find the calibrated specific gravity or pressure/temperature for my meter?

Accepted Answer

The calibration conditions are printed on the meter nameplate. If the nameplate is not legible, contact Northeast Controls with your model number for calibration data.

Flo-Gage™ Troubleshooting Guide

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