The vintage model Honeywell ST7100 thermostat is well known for being good, long lasting work horses. They can last as long as 25 - 30 years. However, they are not indestructible, so at some point it may develop a fault and need to be replaced. So, whether being replaced either due to a problem with the unit, or because of a need / desire to upgrade, a time will come when a replacement will be in order. Some owners of this model don't care about upgrading and just want another ST7100. This way its an easy, direct rewire and provides another 10 years minimum of hassle free heat programming.Want to find a brand new Honeywell ST7100 Thermostat - Good luck with that. Honeywell don't produce this model anymore, but it can still be found for sale either used or "like new" occasionally on eBay.
Honeywell ST7100 Thermostat Replacements
There are many models that can work as direct replacements for the ST7100, but the most common two are listed below. Please be aware: The wiring will not be the same, but it is very easy fit / swap over. The back plate is also different. Rewiring instructions are provided with each unit below that show the correct way to rewire these models when it was the ST7100 that was previously installed.
Honeywell ST9400A1002 (24 hour, 2 Channel) Programmer
Quick Specification / Features:
- Big bright blue back lit digital display
- Automatic seasonal time change
- Fits standard black plate
- 24 hour, 2 Channel
- Backward compatible
- Extremely cheap to buy
Honeywell ST9400C Programmer (7 day - 2 Channel)
Quick Specification / Features:
- LoT Technology integrated
- Big blue digital Display
- Factory set clock
- Auto Season time change
- 7 Day or 5/2 Day operation
- 3 on and off cycles each 24 hours
