Non-Return Valve

John Guest check valve

In-line valve designed to allow flow in one direction and limit return flow in the opposite direction within a compatible installation.

Measurements

Available for 3/8" and 5/16" tube, depending on the variant.

Application

Used when you need to control the flow direction and reduce unwanted backflow within a line.

Installation

Depressurize, identify the valve’s functional direction, cut the tubes straight and insert fully. Check operation and leak tightness before putting into service.

Maintenance

If you notice restriction or abnormal backflow, check the valve’s orientation, cleanliness and condition. Do not assume that a check valve replaces other safety devices in the system.

Frequently asked questions

What sizes are available?
3/8" and 5/16".

Does it have a flow direction?
Yes, the functional direction must be respected.

Is it a shut-off valve?
No; its function is non-return.

What should I check if no fluid is passing through?
Orientation and possible obstructions.