Pre-Installation Checklist

Warning: Mysa for In-Floor Heating operates on line voltage (120V or 240V). Working with line voltage electricity is dangerous and can result in serious injury or death. If you're not confident in your electrical skills, hire a licensed electrician.

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Before You Start

Complete this checklist before you begin any installation work. It takes 10 minutes and prevents costly mistakes.

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Step 1: Verify Your Circuit Voltage

What you need: A voltmeter (available at hardware stores for $10–$20)

Check Your Breaker Type

Look at your electrical panel and find the breaker controlling your floor heating circuit:

• [ ] Single-pole breaker (narrow, one switch) = 120V circuit
• [ ] Double-pole breaker (wider, two switches connected) = 240V circuit

Confirm with a Voltmeter

1. Turn off the breaker
2. Set your voltmeter to AC voltage
3. Turn the breaker back on
4. Carefully touch the voltmeter probes to the breaker terminals (or ask an electrician to do this)

Expected readings:

• Single-pole breaker: ~120V
• Double-pole breaker: ~240V

Important: If your voltmeter reading doesn't match your breaker type, consult a licensed electrician before proceeding.

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Step 2: Verify Wattage Requirements

Your floor heating system has a wattage rating. Mysa for In-Floor has maximum load limits:

Check Your Heating System

• [ ] Find your floor heating system's wattage (on the mat, documentation, or manufacturer specs)
• [ ] Write down the wattage: __________ W
• [ ] Verify it's under the max for your voltage:

- 120V system? Must be ≤ 1,900W - 240V system? Must be ≤ 3,800W

If your system exceeds these limits: Mysa cannot safely control it. Contact your heating system manufacturer or a licensed electrician for alternatives.

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Step 3: Confirm Floor Sensor Location

Before installation, decide where your floor temperature sensor will go:

• [ ] Sensor location planned: Choose a spot within 15 feet (3 meters) of your thermostat in the heated area
• [ ] Protected placement: Ensure the sensor won't be damaged by foot traffic, furniture, or water
• [ ] Good sensor location examples:

- Under a floor tile or mat (covered, protected) - In a small conduit tube under the floor - Taped to the top of the heating mat in an inconspicuous area - Ask your floor heating manufacturer for their recommendation

Note: The included floor sensor is 15 feet long. If you need a longer sensor, compatible 5K–40K Ohm sensors are available separately.

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Step 4: Turn Off the Breaker

Before touching any wires:

• [ ] Locate the breaker controlling your floor heating circuit
• [ ] Switch it to OFF
• [ ] Leave it off during the entire installation

Test for Power

Use a non-contact voltage detector (a pen-sized safety tool, ~$15):

1. Clip it to your non-contact voltage detector
2. Touch it near the circuit breaker wires
3. It should not beep or light up
4. If it does, power is still on — call a licensed electrician

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Step 5: Verify You're NOT on a GFCI Circuit

Important: Mysa for In-Floor has a built-in Class A GFCI (Ground Fault Circuit Interrupter) that cannot be disabled. Installing it on an existing GFCI-protected circuit will cause false trips and prevent operation.

Check for These:

• [ ] Your breaker is not labeled "GFCI"
• [ ] Your breaker is not labeled "GFI"
• [ ] There is no GFCI outlet (outlet with Test/Reset buttons) on this circuit
• [ ] You've confirmed with a licensed electrician (if unsure)

Why This Matters

If you install Mysa for In-Floor on a GFCI-protected circuit:

• The built-in GFCI will constantly trip
• Your floor heater won't run
• You won't be able to use the system

Solution: If your current circuit is GFCI-protected, have an electrician install a new non-GFCI circuit for your floor heating system.

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Step 6: Gather Your Tools

Before installation, make sure you have:

• [ ] Voltmeter — to verify circuit voltage
• [ ] Non-contact voltage detector — to test for power
• [ ] Screwdrivers — flat and Phillips head
• [ ] Wire strippers — to expose about 3/4 inch of wire
• [ ] Needle-nose pliers — to insert wires into terminals
• [ ] Flashlight — to see inside the wall box
• [ ] Thermometer (optional) — to verify your floor sensor works after installation

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Step 7: Verify Your Wall Box

Your thermostat must fit in a standard electrical box:

• [ ] You have access to an empty wall box (or someone to install one)
• [ ] The wall box is in a location convenient for temperature control
• [ ] The wall box is not in a humid area (bathroom walls, near windows)
• [ ] The wall box is away from direct sunlight

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Installation Readiness Checklist

Before calling an electrician or starting installation:

• [ ] Voltage verified (120V or 240V)
• [ ] Wattage confirmed (under max limits)
• [ ] Breaker switched off
• [ ] Power confirmed off (tested with voltage detector)
• [ ] GFCI circuit ruled out
• [ ] Floor sensor location planned
• [ ] Tools gathered
• [ ] Wall box ready

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Next Steps

Ready to install?

• Review our Wiring Reference Guide for terminal connections
• Follow the detailed installation instructions that came with your Mysa for In-Floor

Not sure about the wiring?

• See DIY vs Professional Installation to decide if you should hire an electrician
• Share the Wiring Reference Guide with your electrician

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Need Help?

If you encounter any issues during this checklist or have questions about your electrical setup:

Email: install@getmysa.com

Our team can help you verify your setup or recommend a qualified electrician in your area.