We often get the question:
“I really need a way to stop my tenants from cranking the heat up to 90 degrees. Do you know of any line volt thermostats that can limit the heaters, ie: no more than 72 degrees?”
Honeywell seems to think of everything and they certainly have this one covered at a great price point. Here are Range Stop/Locking Screws that install in the two thermostats below:
https://morelectricheating.com/default.aspx?page=item%20detail&itemcode=HNYWLTST10033
272804A T-Stat Range Stop/Locking Screws – Honeywell Assembly for use with T410, T498 & T4398 Electric Heat Thermostats – Locking cover screws and range stops-two plastic pins to insert inside cover for field-selection of minimum and maximum temperature settings.
Here is a basic white dial type thermostat for 120V or 240V which uses hidden pins inside the cover to limit the temp range:
https://morelectricheating.com/default.aspx?page=item%20detail&itemcode=MARKEL503303
and they install in the gold version as well:
https://morelectricheating.com/default.aspx?page=item%20detail&itemcode=HNYWLTST10009