How to Troubleshoot Ball Seals on Honeywell Boiler Zone Valves

Turn off the household water supply valve.

Locate the Honeywell zone valve power head, which looks like a dial attached to a plate, and is commonly set right above the boiler.

Open the drain valve on the pipe where the zone valve head is connected and hold an empty container under the drain valve. This is especially important if the Honeywell zone valve is an older model. Allow the water to completely drain from the pipe.

Remove the screws holding the head in place with a Philips-head screwdriver, noting that newer heads have one screw on each side of the head and older heads have two screws on one side and two screws on the bottom.

Locate the flange on the head with the ball and remove the old O-ring seals. O-ring seals look like a black plastic ring.

Slide new O-rings, available through Honeywell or in many home retail or hardware stores, onto the body of the zone head.

Align the dimples on the flange with the dimples on the body of the head and place the head back on the pipe. Screw the bolts back into place in a clockwise motion until no gaps remain between the bolts and the head.

Turn the water supply back on to verify that there are no leaks. Once there is no water leaking, line the zone head up until the post exits the flange. Rotate the two screws clockwise until firm.