Installing a Smart Thermostat

 Air conditioning system and original thermostat

Original  Braeburn 2020 programmable
thermostat provided by Flagship Marine.

A new air conditioning system was installed mid 2015 in Johanna Rose.  The system, manufactured by Flagship Marine, is model FM16R which is a 16,500 BTU AC with digital 2KW heat element.  The manufacture provides a Braeburn 2020 programmable thermostat to control the system. This is an ordinary  thermostat that is common in most households.

Honeywell Lyric T-5 WiFi Thermostat

Honeywell Lyric T-5 WiFi
thermostat

I recently installed a Honeywell Lyric T-5 smart thermostat at home and was impressed by its performance.  While the Lyric T-5 may not have all the bells and whistles of a $300+ smart thermostat, it has all the bells and whistles that I'm interested in using and at 1/3 the cost.

While the Lyric T-5 can work with Apple's HomeKit and Amazon's Echo, I find that the Honeywell Lyric/Home iPhone app and the free Honeywell cloud services works fine.   I can check and control the current temperature remotely.  As with most thermostats, the temperature can be scheduled to change settings at various times of the day and days of the week.  But the geofence feature allows for an added control layer of home and away.   Within the Honeywell app, one sets a circular geofence, and when one enters or leaves the geofence, the system changes to home or away mode settings.

I soon convinced myself that I needed one for the boat.   Having the ability to turn on the AC prior to arriving at the boat is a real luxury. This is especially nice since I live about a 2 hours drive from the boat.  Of course, smart thermostats requires constant internet access, but nowadays this is not a problem.  A few years ago I installed a long range WiFi system which includes a dedicated WiFi network for the boat.   The added advantage of a dedicated system is that all network enabled devices (i.e., phones, computers, iPads, AppleTV, Raymarine Chart Plotter, ...)  connect to the boat Wifi.   The boat WiFi gets internet access from an Ubiquiti Bullet WiFi radio. 

Thermostat Wiring

Installing the Lyric T-5 at home was straight forward and simple.   The old thermostat was removed and the 5 color coded thermostat control wires were connected to the color code inputs of the Lyric T-5 mounting socket.  Once the T-5 is plugged into the mounting socket, the device powers up.  One  then downloads and runs the Lyric iOS app following app instructions to set the device up.  For my home installation, it took about a minute to get working. Nice, simple, and quick.

Installing the Lyric T-5 on the boat required more effort.  This was because the Lyric T-5 requires a common ""C"" wire to power the unit.   Most home AC system have the common ""C"" blue wire as one of the color coded wires in the thermostat cable.  The boat AC system did not.  The Flagship Marine thermostat uses a 9V battery for power and 4 control wires(see photos below). 

Original mounting socket for the Braeburn 2020.

Thermostat wire buss bar mounted on the Flagship Marine
remote control panel.   The top 4 wire lead to the 
Braeburn 2020 thermostat.

Installation

I sent Flagship Marine an email inquiring about access to a common "C" for the Lyric T-5.  Kudos to Flagship Marine for responding 26 minutes later with diagrams and instructions on accessing the transformer 24VAC common for the common "C" 5th blue wire.  For only a few dollars, several feet of a thermostat control cable with 5 standard color coded wires were purchased at a local Home Depot.  The thermostat control cable was connected to the Lyric mounting socket replacing 4 original wire control cable.  Four of the wires were connected to the AC control buss(see photo above).  A separate short blue wire was run from the control buss inside the control panel to the transformer 24VAC common.  The 24VAC common was accessed at through a small yellow wire which connects the transformer to all relays.  The blue wire connection was made using a 2 male 1 female spade connector at the blower transformer.  At the control panel buss, the blue wire was connected with spade connectors to the blue wire of the thermostat control cable.  Note, there is another larger yellow wire which actually runs out to the control panel buss. This larger yellow wire is for the compressor and is not to be confused with the smaller yellow wire of the 24VAC common.   The Lyric T-5 was then plugged into the mounting socket and the set up was performed as described above for the home installation (i.e. follow the app instructions).

Honeywell has recently updated the iOS Lyric app improving the app performance and changing the app's name to "Honeywell Home".

Access to the transformer 24VAC common.
The transformer is located center right shown
with white label. 

Wire diagram for low voltage system.
The 24VAC common is the yellow diagram
wire running from the transformer 

A 2 male 1 female spade connector
was used to tap into the transformer
24VAC common.

Thermostat wire buss bar mounted on the
Flagship Marine remote control panel.   The 4
original thermostat wires plus a 5th (blue) lead
to the  Honeywell Lyric T-5 Smart thermostat.
The 5th blue wire is connected a white wire
through male/female spade connectors with
a shrink tube boot. The white wire is connected
to the 24VAC common. 

 Lyric T-5 mounting socket with the 5 wire required for operation.  The thermostat plugs in and automatically powers on for set up. 

Honeywell Lyric T-5 WiFi thermostat in operation.

Screen shot of Honeywell Lyric
iOS app controlling the thermostat.
Honeywell has recently updated the
iOS Lyric app changing the app
name to "Honeywell Home".