# Error code E74: no heat call

> E74 means Halo asked for heat but the system didn’t respond. Check the W1 wire and the furnace filter.

Source: https://helpdox.fekbd.com/docs/halo-thermostat/troubleshoot/error-code-e74-no-heat-call/

E74 means Halo asked for heat but the system didn’t respond. Check the W1 wire and the furnace filter. Here is exactly what to do.

## Steps

1. 1Check W1Make sure the W1 wire is fully pushed in.
2. 2Check the furnaceReplace a clogged filter and check for furnace error lights.
3. 3Run a testApp → Settings → Equipment → Test heat.

Tip

If the furnace shows its own error code, call your HVAC technician.

## Still stuck?

Have your serial number ready (Settings → About on the thermostat, or the label on the back plate).