GFCI Requirements — Mysa for In-Floor Heating

Mysa for In-Floor Heating includes permanent Class A GFCI protection with a 5 mA trip level. It is always on and cannot be disabled.

Do not install on an existing GFCI circuit

Electrical code requires GFCI protection on in-floor heating circuits, so many homes already have a GFCI breaker or GFCI outlet on that circuit. Two GFCI devices on one circuit conflict, causing constant nuisance trips and preventing the floor heater from operating.

If the circuit already has GFCI protection, have an electrician install a standard (non-GFCI) breaker before using Mysa.

The controls on the thermostat

• TEST — checks that the GFCI responds to a fault. The FAULT light turns on and heat disconnects.

• RESET — restores normal operation after a trip or test.

• FAULT light — on when a ground fault is detected or TEST was pressed.

A GFCI detects current travelling an unintended path to ground. It does not protect against circuit overloads or short circuits.

Repeated trips point to a real fault. Never bypass the GFCI — have the system inspected by a qualified electrician.