The Watts CSM-81-F 4 is a 4" manual circuit balancing valve with Flanged connections. It features a semi-steel body and a ptfe seat.
This 4 inch flow measurement valve monitors system flow in medium to high flow rate HVAC units providing a highly accurate flow measurement. It consists of semi-steel body construction with a low-torque cylindrical plug design, flanged end connections, checked metering ports with drip caps, position indicator plate, positive shutoff, and two brass pressure taps. It is ideal in hot/chilled water units such as fan coil units, water source heat pumps, reheat coils, panel coils, branch lines, and pumps.
Features
- Accurate flow measurement
- Flanged end connections
- Positive shutoff
- Low torque
Common Questions
- Do I need a separate meter to read the flow?
- Yes. The CSM-81-F 4 is a differential-pressure device: it meters through dual PT (pressure/temperature) ports with checked drip caps. You connect a balancing meter (or a differential gauge) across the two ports, read the pressure drop, and convert it to GPM using the Watts flow chart for the 4" body. The valve does not display flow on its own. If you want set-and-read balancing without a meter, use the Watts iDROSET CSD direct-reading series instead.
- Can it also shut off the circuit?
- Yes. The CSM-81-F 4 gives positive, drip-tight shutoff, so it doubles as the service valve for the circuit and you do not have to buy and install a separate ball valve next to it. The memory stop preserves your balanced setting: close the valve for service, reopen it against the stop, and the circuit returns to the same flow without rebalancing.
- Can I use it on a domestic hot water recirculation line?
- No. The CSM-81-F 4 is not a lead-free model, so it is restricted to closed hydronic heating and chilled-water loops and other non-potable service. For DHW recirculation balancing, choose the lead-free equivalent — the Watts LFCSM-61-S (PT-port) or LFiDROSET CSD (direct-reading).
Specifications
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Type: Balancing
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Size: 4"
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Inlet Size: 4"
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Outlet Size: 4"
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Connection: Flanged
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Body Material: Semi-Steel
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Seat / Seal Material: PTFE
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Application: Hydronic Heating/Cooling
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Country of Origin: United States
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Warranty: 1 Year Limited
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MPN: CSM-81-F 4
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Lead-Free: No
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Balancing Type: Manual Circuit Balancing
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Valve Functions: Balancing;Flow Measurement;Shutoff
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Flow Readout: Dual PT ports, 1/4" SAE 45° flare, checked w/ drip caps
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Memory Stop: Yes
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Positive Shutoff: Yes
