What does em mean on thermostat?

What does em mean on thermostat?

emergency heat
What is EM heat on thermostat settings? Short for “emergency heat,” it is a setting that controls your home’s back-up heating system. If you have an emergency heat thermostat setting, you likely have a heat pump, as well as a gas, oil, electric, or hot-water back-up system.

Where does the e wire go on a thermostat?

The E terminal has a back-up heat source. If you have a heat pump package unit, the E terminal should be wired directly to the heating relay or the stripboard of the air handler.

What does E and F mean on thermostat?

What is the purpose of the fan operation switch? The thermostat fan operation switch, labeled FUEL SWITCH in the diagram below, is factory-set in the “F” position. The “E” setting will allow the fan to turn on immediately with the heating or cooling in a system where the G terminal is connected.

What is the E terminal on a Honeywell thermostat?

Emergency Heating
E – This thermostat terminal is for heat pumps and stands for Emergency Heating. If for whatever reason the heat pump condenser fails and it is necessary to run the heat there is an option on heat pump thermostats for emergency heating.

Should I use em heat?

Short answer: No. Switching your thermostat to emergency heat or “em heat” just because it’s cold outside will just raise your energy bills like crazy. Don’t use emergency heat mode unless your heat pump stops heating your home altogether. If that happens, contact a professional heat pump repairman for help.

Is it OK to use emergency heat?

Emergency heat without air movement can cause damage do your outdoor unit. You should never turn on the Emergency Heat manually, unless your heat pump has failed completely. If that is the case, you should have your heating unit examined and repaired immediately.

Do I need the E wire on my thermostat?

Some thermostats have an E wire. The E wire controls emergency heating. Emergency heat is used when the HVAC system is not functioning properly (usually when the compressor is out of service). When you set a thermostat to emergency heat, the system bypasses the compressor and directly accesses the electric heat strip.

What color is E wire on thermostat?

Thermostat Wiring Color Code Chart

Marking Wire Color Code Description
E Brown Emergency heat relay
Y Yellow Primary cool call relay
Y2 Yellow Secondary cool call relay
G Green Fan relay

What does F stand for on a thermostat?

Factory-set in the “F” position, the thermostat fan operation switch is labeled FUEL SWITCH. It’s the correct setting for most systems. The switch should be set to “E” if you have an electric heat system.

What is E on thermostat wiring?

E. Some thermostats for heat pumps have an E terminal, which toggles emergency heat on or off. Emergency heat should only be used on very cold days when the heat pump is unable to keep the house warm. The E wire normally connects to the ecobee’s W1 terminal.

What is W2 and E on a thermostat?

That is why, on many old thermostats, you would jumper Y1 and W1 in a heat pump application. W2 – Means second-stage heat. E – Is emergency heat, usually just a way to manually drive on what would normally be the secondary form of heat without stage 1 heating.

What are the different wires for a thermostat?

Green – The green wire connects to the fan. Orange – This wire connects to your heat pump (if you have one). Red – Now, there can be two separate wires for this. One is for cool and the other is for heat, hence the abbreviation “RH” and “RC”. Blue – This is your common or “C” wire.

Where does the Red Wire go on a thermostat?

Yellow – The yellow wire connects to your compressor. Green – The green wire connects to the fan. Orange – This wire connects to your heat pump (if you have one). Red – Now, there can be two separate wires for this. One is for cool and the other is for heat, hence the abbreviation “RH” and “RC”.

What do the letters W and W mean on a thermostat?

W, W1, W2: Just like the Y wire, the W wire (s) control the heating aspect of your system. O, B, O/B: These wires are responsible for switching the changeover valve in a heat pump system. The O wire reverses the valve from heating to cooling, and the B wire switches the valve from cooling to heating.

What do the letters mean on a Honeywell thermostat?

L: This terminal is designated for indicator lights on the thermostat, sometimes for when auxiliary or emergency heat is turned on, or if there’s a general problem with your system. K: Honeywell wire saver modules combine the Y and G wires to form a single K wire that connects to the K terminal on some Honeywell thermostats.