Erwel

Erwel is a steam trap name, and the parts on this page are listed for two kinds of Erwel trap: float and thermostatic traps, and thermostatic traps. The working parts that get replaced are the capsule in a thermostatic trap, and the float and air vent in an F&T trap.

BoilerSupplies.com carries a repair part for each of those. A capsule that fails open passes live steam, and the return lines run hot. A capsule that fails closed holds condensate, and the radiator or coil behind it goes cold. In an F&T trap, a float that has taken on water stops opening the valve, so condensate backs up. A worn valve and seat lets steam blow through. The kit is the repair part for the F&T faults, and a new capsule for the thermostatic ones.

Key facts

• BoilerSupplies.com lists two repair parts for Erwel steam traps: a capsule and an F&T kit.

• A capsule for an Erwel thermostatic trap opens on cooler condensate and closes on steam.

• A capsule that fails closed leaves the radiator or coil behind it cold.

• In an F&T trap, the float drains condensate and a thermostatic vent lets air out.

• In-stock small-pack orders placed before 2:00 PM EST, Monday through Friday, ship the same day.

How do I know which Erwel part a failed trap needs?

By the trap type. In a small Erwel thermostatic or radiator trap the capsule is the working part, so banging or a cold radiator there often comes down to the capsule. A larger Erwel F&T trap that floods its coil or blows steam points to the F&T kit for its float and vent internals.

Does an Erwel F&T kit also go by float trap kit or float and thermo repair kit?

Often, yes. F&T and float and thermo are shorthand for float and thermostatic, and some shops say float trap kit for the same repair, though a plain float trap has no thermostatic vent. Erwel Float and Thermostatic Kits is the BoilerSupplies.com listing name for a kit that goes into Erwel F&T traps, rather than the small radiator traps, which take a capsule.

Why does one radiator with an Erwel trap stay cold while the rest of the floor heats?

A thermostatic capsule that has failed closed is one common cause. The trap then holds condensate in the radiator, steam cannot get in, and that radiator stays cold while its neighbors heat. A new capsule for the Erwel trap is the part for that fault.

Can I order from the old Erwel part?

Yes, and it is often the most direct route. Once the old capsule, or the old float and its vent, is out, photograph it beside the trap body with any markings readable. Add the pipe size and how many Erwel traps are going to be rebuilt, then order through BoilerSupplies.com.

Have the Erwel trap type, its markings and a picture of the worn part on hand before calling 1-770-957-9599 or toll free 1-800-780-3776. The same details can go into the request on BoilerSupplies.com.