How to Repair Radiator Valve Threads

In this video, This Old House plumbing and heating contractor Richard Trethewey and host Kevin O'Connor shows how to cut threads for a new radiator air vent.

by Richard Trethewey and Kevin O'Connor, Host

Skill

EasyCutting threads isn’t that difficult, but it takes patience and a steady hand

Cost

$10 to $20

Estimated Time

30 to 60 minutes

In this video, This Old House plumbing and heating contractor Richard Trethewey and host Kevin O’Connor cut threads for a new radiator air vent.

Steps for Repairing Radiator Air Vent Threads

Enlarge the existing air-vent hole in the radiator with a 7/16-inch-diameter high-speed steel drill bit.
Put a ¼-inch tapered tap onto a ratchet wrench and cut new threads into the 7/16-inch hole.
Spread pipe dope onto the threads of a ⅛-inch to ¼-inch bushing, then thread the bushing into the hole and tighten with a ratchet wrench.
Apply very little pipe dope to the threads on the air vent and thread the vent into the bushing; hand-tighten the vent until it’s in an upright position.

Learn More: Thermostatic Radiator Valve Installation

Tools