Nest Gen4 Thermostat general requirements

• Nest Thermostats are designed to work with 24V US spec AC systems. They require installation of a conversion kit as well as bypassing of AC control board in order for them to work with 220V UAE AC systems
• Nest Thermostats can be retrofitted to work on single and 3 fan speed modes
• Single fan speed mode requires the presence of 4 wires to thermostat location
• Three fan speed mode requires the presence of 6 wires
• Thermostat locations with 3 wires, requires the installation of an additional wire saver module to add the 4th wire for single fan speed.
• Less than 6 wires at a thermostat location requires the pulling of a new set of 6 wire panel cables for three fan speed activation
• New ACs with inverter compressor or DC current fan motor require different installation method. The process involves installation of a brand specific interface that interprets Nest signal back to the AC control board plus pulling of CAT6 cable.
• Nest E thermostat can only support one fan speed vs 3 fan speed for the Nest Gen4

Non-compatibility: cases where Nest cannot be installed

• Window type AC units
• VRV type ACs
• Where ACs are connected to a BMS or wired smart home system
• Chilled water systems with modulating actuator motor (1-10v). These require replacement of actuator with on/off model
• UK and European spec Nest thermostats are designed to work with boilers and water heaters and are not configured to work with AC systems

Specific compatibility guidelines

Apartments:

• As a general rule, apartments located within towers are typically served by a central chiller, as such would have 6 wires
• In some newly build apartments with modulating actuator motors, there would a requirement to replace actuator motors with standard on/off models. This can only be established post inspection. Cost of actuators motors varies between AED 350-500 per unit. In very rare cases, valve assembly would also have to be replaced (cost AED 1500 per unit)

District cooling:

• AC units within areas with district cooling such as the Palm, Jumeirah Islands, JLT, Motor City and Sports City would have thermostats with 6 wires

Villas: (in non district cooling areas)

a) LG:

• Found in majority of Emaar villas across Springs, Meadows and Arabian Ranches as well as Al Furjan
• All units have 3 wires to thermostat location
• Requires installation of an additional module (add 4th wire) for single fan speed
• Three fan speed requires pulling of 6 wires. Smaller capacity units have single stage fan that requires installation of fan transformer (AED 390)
• Installation of Nest thermostat on new LG ACS with modulating compressor and DC fan motor is not yet supported.

b) OGeneral:

• Found in many Emaar villa communities.
• All units have 3 wires to thermostat
• Requires installation of an additional wire saver module that provides 4th wire for single fan speed.
• Three fan speed installation requires pulling of new 6 wire cables
• New OGeneral ACs with modulating compressor and DC fan motor. Require installation of a bespoke Nest interface/module approx cost (AED 900) per module

c) York & Daikin:

• Both York and Daikin units would have 4 wires through to thermostat location
• York prevalent in The Villa project. Daikin is installed in all Arabian Ranches 2 communities

d) Trane:

• Older units would have 8 wires through to thermostat location
• Newer units with LCD type thermostat would have 2 wires going to thermostat location
• Prevalent in Jumeirah Park and other Nakheel communities

e) Carrier:

• Mexican spec : 4 wires
• Egyptian spec: 5 wires (found in Damac Hills), requires wire saver for 3 fan speed.
• Egyptian spec: 4 wires (found in Arabella Mudon), ACs have inverter compressor and DC fan motors. Requires interface module.

f) Midea:

• Found in Mira Oasis and Maple Villas in Dubai Hills
• Units on ground floor are standard 5 wire AC current fan motor. Requires wire saver for 3 fan speed operation
• Units found on first floor are inverter compressor/DC current fan motor. These require pulling of CAT6 cable and installation of interface module

g) Samsung:

• Comes in two variants 4 wire AC fan motor (Legends Villas) and 2 wire inverter compressor (Sidra, Dubai Hills)
• Samsung ACs in Sidra require specific interface (AED 950) pulling of 6 new wire cable and installation of conversion bo

h) Rheem : 6 wires found in Mira and 5 wires found in Lantana. ACs in Lantana can only support 2 fan speed as medium and high speeds are looped on AC.

i) American breeze: 6 wires found in some older Emaar villas in Meadows and Lakes as well as Jumeirah Islands

j) Mitsubishi: All Mitsubishi units require pulling of new wires as well as installation of an interface (provided CN90 connector is present on PCB). Found in older villas of non-free hold communities

k) Honeywell: Very rarely installed in villas. Would typically have 6 wires

l) Trane: 8 wires, found in some Jumeirah Park villas. Villas in newer districts would have 2 wire Trane AC in which case new 6 wire cable have to be pulled