Thermoplastic valves in PVC, CPVC, polypropylene and PVDF handle acids, caustics, brine and ultra-pure water at modest temperatures and pressures. Water treatment, chemical dosing, plating and pharmaceutical plants use them heavily.
Plastic valves degrade in ultraviolet light and become brittle with age, so storage conditions matter more than service hours. New old stock stored indoors is the strongest category; material left outside in the Louisiana sun is a different proposition.
Review points
What decides the value of pvc and cpvc valves
UV exposure
Sunlight embrittles PVC and CPVC. Indoor storage is worth considerably more.
Material
PVDF and PP hold value better than PVC.
Solvent weld ends
Check that the socket ends have not been distorted or contaminated.
Selling it
How to present the lot
Count by size and pattern, and note the marking on the body. If you have certificates, include them; if you do not, say so rather than implying they exist.
Do not separate trim from bodies to sell them individually unless the trim is clearly identifiable and valuable on its own. In most cases the assembly is worth more together.
Questions sellers ask
Do you buy used plastic valves?
In quantity and in good condition, yes. New old stock is much stronger.
Are CPVC valves worth more than PVC?
Generally yes, because of the higher temperature rating.
What about PVDF?
PVDF is the highest-value thermoplastic valve material and is always worth reviewing.