The McMaster-Carr 4609K75 polypropylene float valve delivers automatic tank level control with chemical resistance up to 175°F, outperforming standard PVC in heated process water and RO storage applications. Designed for 1/4" OD plastic tubing with compression fitting, this compact valve mounts directly in open tanks and delivers 1.59 GPM flow with reliable Buna-N sealing.
SPECIFICATIONS
Technical Details
| Model Number | 4609K75 |
| Material | Polypropylene body with brass float rod |
| Connection Type | Compression fitting for 1/4" OD plastic tubing |
| Flow Rate | 1.59 GPM |
| Temperature Range | 33° to 175°F |
| Maximum Pressure | 125 PSI |
| Float Arm Length | 5 3/4 inches |
| Seal Material | Buna-N (nitrile rubber) |
INSTALLATION & USE
Mounting and Connection
- Mount valve vertically through tank wall or lid opening with unthreaded outlet positioned inside tank for gravity feed
- Insert 1/4" OD plastic tubing into compression fitting and tighten collar hand-tight, then one quarter turn with wrench
- Adjust float arm angle to set desired shutoff level, ensuring float travels freely without obstruction
- Test operation by filling tank slowly and verifying complete shutoff at target water level
COMPATIBILITY
Recommended Applications
Ideal for automatic fill control in reverse osmosis storage tanks, atmospheric water storage, chemical dosing reservoirs, and process water holding tanks where temperatures exceed PVC limits. Works with polyethylene, polypropylene, nylon, and LLDPE tubing in 1/4" outside diameter. Compatible with most chemicals, acids, and alkaline solutions within polypropylene's resistance range. Not suitable for pressurized tank installations or systems requiring NSF-certified components for potable water.
🔧 Pro tip: Secure the float arm at a steeper angle than you think necessary during initial setup. Most overflow issues come from insufficient float travel distance, not valve failure. Test with a slow fill first to confirm shutoff point before connecting to full supply pressure.
