Mysa C-Wire Power Adapter

Provides reliable 24V power to your Mysa thermostat when no C-wire is available. Installs at your furnace, boiler, zone equipment or air handler.

$30.00

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assignment_return Essai de 30 jours sans risque avec retours gratuits
delivery_truck_speed Livraison gratuite pour les commandes de plus de 100 $
shield Garantie de 5 ans, la meilleure de sa catégorie
timer Livraison rapide en 3 jours ou moins

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Pricing details
  • Adaptateur secteur Mysa C-Wire × 1 $30.00
$30.00

Many homes don't have a C-wire at the thermostat, and running new wire through walls is a hassle. The Mysa C-Wire Power Adapter provides continuous 24 VAC power to your Mysa Smart Thermostat by repurposing your existing wiring. Designed to handle the trickiest installations, including two-wire heat-only and cool-only systems where you have just R and W (or R and Y) at the thermostat.

Check Gas and oil furnaces
Check Air conditioners and heat pumps
Check Hot water boilers with hydronic systems
Check 24V zone valves and zone valve control boards
Check 24V relay configurations
Check Millivolt/dry contact configurations (many fireplaces)

Works with Mysa Smart Thermostat only

Installation happens at your furnace, boiler, air handler, or zone valve panel. Our online guide creates custom instructions based on your exact wiring setup—with 11 different diagrams covering most configurations.

Standard installation (furnace/air handler):

  1. Turn OFF power at the circuit breaker
  2. Locate control board
  3. Label existing thermostat wires using included stickers
  4. Photo your wiring for reference
  5. Reroute wires through adapter following your custom guide
  6. Mount adapter using included adhesive pad
  7. Restore power and verify thermostat displays

Boiler and zone valve systems: For hydronic systems with zone valves, install the adapter at the zone valve—not the boiler aquastat. Multi-zone setups need one adapter per thermostat.

External transformer option: Older boilers or systems without adequate 24V power can use the Rext terminal with a standard 24 VAC transformer (sold separately, ~$15–20 at hardware stores). One transformer powers up to three Mysa + adapter combinations.

Model: MYSA CWA V2-0

Input Voltage: 20–30 VAC

Current Rating: 8A (2A max on W/Y/OB)

Operating Temperature: 0°C to 50°C (32°F to 122°F)

Relay Type: Isolated dry contact

External Power: Rext terminal for 24 VAC transformer

Wire Harness Length: ~12" (30 cm)

Ingress Protection: IPX0

Dimensions: [placeholder - to be added]

Colour: White

Notre politique de retour est simple. Les factures d'électricité élevées ne reviendront pas. Toutefois, si vous devez retourner votre Mysa, c'est tout aussi simple : expédition et retours gratuits, avec un soutien d'experts à chaque étape.

Vous exigez la durabilité. Après un million d'appareils vendus et des années de perfectionnement technique, nous garantissons la fiabilité des nôtres. C'est pourquoi chaque Mysa inclut une garantie de 5 ans—plus du double de la norme de l'industrie.

Que contient la boîte

Caractéristiques

Bolt Reliable 24V Power
Build No New Wiring
House Two-Wire Ready
Quick_Reference Custom Install Guide
Package_2 Hardware Included
Eco Less E-Waste

Contrôlez de partout

"Les 4 meilleurs thermostats intelligents de 2025"

~ Wirecutter / New York Times

"Fonctionne comme prévu… j’ai enfin pu me débarrasser du vieux thermostat des années 1980 qui ne faisait que chauffer au maximum."

~ Derek F.

"Fait une bien meilleure job que les autres thermostats intelligents que j’ai utilisés, et l’application te donne toute l’info dont t’as besoin pour tirer le maximum de ton budget de chauffage."

~ Ian V.

''Le guide étape par étape m’a vraiment aidé et a rendu les choses plus faciles pour un installateur débutant comme moi.''

~ Chris L.

'L’équipe d’assistance Mysa est formidable ; Leigh m’a aidé avec l’installation et a rendu l’ensemble du processus très fluide.''

~ Anmol A.

'Fiable, élégant et nettement amélioré.''

~ La Presse

Foire aux questions

Can I install this myself?

Yes. Installation requires basic comfort with electrical wiring at your furnace or boiler. Our online guide creates custom instructions for your exact setup with 11 different wiring diagrams. If you're uncomfortable working with HVAC wiring, hire a qualified technician—typically $75–150.

Do I need the C-Wire Power Adapter?

Over 55% of compatibility checker submissions need the adapter. Homes built before 2000 and hydronic heating systems are most common.

What's included?

The adapter, wire connector for external transformer setups, adhesive mounting pad, wire label stickers, and installation guide.