1. Unplug kiln or disconnect from power supply and lock out if in a commercial or industrial setting.
2. Open the control box.
3. Photograph the relays to remember to return the wires in the correct order.
4. Remove the wires to the relay.
5. Remove the nuts from the studs holding the relay. Remove old relay and replace with new one.
6. Visually inspect the wire connectors. Do they look corroded or singed? Are the wires frayed? Is there corrosion on the wire itself? If any of this is questionable, you should replace the appropriate wires.
7. Reconnect all wires. Visually inspect to make sure the spade connectors are down as far as they can go and feel to see that they are tight (a gentle tug should not remove one). If they are loose, remove the wire and slightly squeeze the spade connector with pliers to tighten it.

IMPORTANT: The slip-on wire connectors cannot be loose or corroded. If there is a bad connection, heat will be generated, and the component they slip onto (relay, terminal strip, etc.) may overheat and fail. If you squeeze the slip on the terminal to make it tighter, squeeze it evenly so that one side is not tight, and the other is loose. If there are any doubts about the integrity of the wire or the connector, replace the whole wire or harness.

Checking a Relay with a Multi-Meter

Changing a Relay

Parts

1. See this page for the 12 Volt 30 Amp relay we use for most kilns.
2. See this page for the 240 Volt 30 Amp relay we use as a control relay for 480 volt kilns.
3. See this page for all contacts and relays.