A double back check fill valve uses two independent check mechanisms in series, so propane can flow into the tank during filling but cannot flow back out through the fill connection. The second check provides redundancy if the first fails or is held open by debris. It is the standard fill valve arrangement on ASME propane tanks.

The 1 3/4″ ACME outlet is the standard bulk delivery connection used by propane delivery trucks in North America. It allows any standard delivery hose to couple to the tank. The 1 1/4″ MNPT inlet is the threaded connection into the tank itself.

ASME tanks are stationary vessels built to a different code and are filled in place by a delivery truck, so they use fill valves like this one. DOT cylinders are portable and are taken to a filling facility, using different valve types such as POL or OPD. The two are not interchangeable.

Yes, the cap protects the ACME threads and the check mechanism from dirt, water, and physical damage between fills, and it is a required part of the assembly. This valve is supplied with a cap and strap. A missing cap is a common cause of check valve fouling.

Match the inlet thread, the outlet connection, and the valve type, which here are 1 1/4″ MNPT, 1 3/4″ ACME, and double back check. Those three specifications determine interchangeability far more reliably than a part number alone. Send us the part number being replaced and we will confirm the equivalent.

Yes. We supply valves, fittings, and cylinders at wholesale to propane marketers, tank fabricators, and distributors. Request a quote with the part specification and quantity.

Fill valves are replaced when a check fails to seat, when threads are damaged, or on the schedule set by the tank owner’s maintenance programme. A valve that weeps during or after filling is the usual symptom of a failed check. Replacement is qualified work and must be done by trained personnel.

It fits ASME tanks with a matching 1 1/4″ MNPT fill opening, which is a common configuration but not universal. Confirm the tank’s fill opening size and thread before ordering. We can advise if the tank specification is supplied with the enquiry.

A fill valve is the point where propane is delivered into the tank; a service valve is where gas is drawn out to the appliance or system. They are separate fittings with different connections and are not interchangeable. A tank normally has both, plus a relief valve and a gauge.

Yes. Installing or replacing propane tank valves is governed by code and must be performed by qualified personnel following the tank manufacturer’s and applicable regulatory requirements. We supply the parts at wholesale to companies performing that work rather than to end users.