1. Remove the panels of the A53.

2. Unplug the wires of the temperature sensor by moving the orange sleeves up and pulling them apart.

3. Remove the old temperature sensor by using a pick to pull the silicone sealant out of the port.

4. Put the new temperature sensor in place, use a small dab of heat resistant silicone sealant to plug the port and then reconnect the wires.

NOTE: Make sure that the temperature sensor is inserted far enough that about 1/2" of the wires go into the boiler along with the sensor. That way the silicone sealant only gets on the wires and not on the probe itself. The silicone sealant only needs to make a plug 1/4" thick. Do not cram the temperature sensor in there and fill the whole space with silicone sealant.