Need Help Wiring My 3-Speed Fan Coil and Valve Actuator to a Nest

[Doitguu123]

I’m trying to connect my condo fan coil system to a Google Nest and I’m not sure how the wiring should be done. My old thermostat has separate terminals for low fan, medium fan and high fan, plus a valve actuator for heating or cooling. I also have two extra wires labeled SC and PS.

Can anyone explain how this should be wired if I switch to a Nest? And is there any way to make it work through the Nest Pro installation setup? I’m trying to figure out if the Nest can handle this system or if I need adapters or relay modules. Any guidance from people who have done this would help a lot.

[Patrick_Caezza · Accepted solution]

@Doitguu123 

Post a picture of the original thermostat's wiring here

[Patrick_Caezza · Accepted solution]

@Doitguu123 

Post a picture of the original thermostat's wiring here

[Doitguu123]

 

[Patrick_Caezza · Accepted solution]

@Doitguu123 

Are those solid or stranded wires?

Do you know who the manufacturer and the model number of the thermostat are?

[Doitguu123]

I'm pretty sure they're solid wires and it's a unilux thermostat

[Doitguu123]

This is the original thermostat

 

[Doitguu123]

Can't find the original thermostat online but this is exactly the same but just a bit of a different company

Honeywell Digital Fan Coil Thermostat - 24 VAC (low voltage)

https://uniluxdirect.com/collections/thermostats/products/digital-thermostat-low-voltage-24-vac