How to replace a thermal protector

The following presentation shows the proper procedure for replacing an over-temperature protector. This matches the procedure found in our getting started installation instructions. The first step, of course, is for your safety. Shut off the equipment and plan an appropriate lockout tagout to the electrical supply. Once you can access the heater, proceed to remove the top of the heater head. Some heads have a cap that will unscrew, while others have bolts that need to be removed. Retain everything to be reinstalled at the end of the procedure. Marking where the protector wires exit the protector well is a good step to ensure that the replacement is installed in its proper location: at the very bottom of the well for heaters with multiple protectors. Make a note of the wiring arrangement with the wire nuts to ensure the proper wiring of the replacement. After the wiring has been properly noted, proceed to remove the wire nuts and separate the wires. Retain the nuts for use later. If you do not know which of the protectors needs to be replaced, now would be the time to test each one with an ohmmeter. A tripped protector will measure as an open circuit, while an untrimmed protector will measure continuity. And some heaters the top of the protector well is covered with electrician’s putty. Remove and retain the putty for use later. You can now remove the trip protectors from the heater. Now you can use the tripped protector as a guide to trim the wires on the replacement protector. This step will prevent you from trying to stuff a lot of excess wire under the heater head cap. Do not trim the wires too short, or the protector will not be able to reach the bottom of the protector well and will be useless. If you do happen to trim the wires too short, scrap the protector and start again with a new one transferring the marks from the wires on the tripped protector to the wires on the replacement. Again, this will ensure that the replacement will be installed in its proper location. At the end of the protector well, inspect the empty protector well to make sure they are clean and dry any moisture should be removed. Once you have confirmed that the well is dry, you can proceed to install the replacement protectors. Make sure the protector reaches the very bottom of the well. The marks that you transferred to the wires will confirm that the protector is installed to the same depth as the prior one. You can now wire the replacement protector to the lead wires. For a heater with a single protector, this is pretty straightforward. For a heater with multiple protectors, make sure that you follow the wiring pattern noted earlier in this procedure. There are also wiring diagrams for protectors included with our written instructions; please note that the protectors must always be wired in series with each other and with the lead wires. Once the wiring is complete, proceed to seal the top of the protector tubes with either the electrician's putty or some RTV sealant. After that, inspect the O-ring or gasket used to seal the heater head cap. If damaged, contact Process Technology for new items. If the gasket or ring is in good condition, proceed to reinstall the heater head cap. Now is the time to also inspect the heater conduit to make sure it still has a liquid-tight connection to the heater head. If not, repair the connection is needed. Finally, you can remove the lockout tagout and return the heater to service. If you have any questions, feel free to contact our customer service department or visit our website @ www.projectorpheus.com to visit.