# Installing Harman Stoves with a setback Thermostat

- Link: https://hearthsidepatio.com/faq-items/installing-harman-stoves-with-a-setback-thermostat/
- Published: 2019-12-11T20:52:31-05:00
- Author: John Mazza

All Harman pellet units can utilize a setback thermostat. The thermostat must be:

 * Millivolt compatible
 * Have gold contacts
 * be low voltage
 * be low current

Harman recommends the following Honeywell units for this use:

 * RTH230B
 * RTH6300B

If there is a jumper between Rh and Rc, it must be removed from the terminal block
of the thermostat. The thermostat must be connected in series with the room sensing
probe using the Rh and W terminals of the thermostat. Except with the P38, which
has no room sensing probe, the set-back thermostat MUST be used in conjunction with
the room sensing probe.

There are two modes of operation as well:

**Occupied Mode: (someone’s home)**
 Set the thermostat to its max temp setting.
The stove room-sensing probe will control room temperature, so set the desired room
temp on the stoves temp dial.

**Unoccupied Mode: (no one home)**
 Program the thermostat to the desired set-back
temp. When the thermostat opens (is satisfied) the stove will go into a 4-blink 
status. If the stove is a auto-ignite model and the auto/manual switch is in auto,
the stove will shut down. When the thermostat closes (calls for heat) the 4-blink
status will reset and the stove will ignite. If the stove is a manual ignition model,
or an auto-igniting unit with the selector switch set to manual, the stove will 
go into the 4-blink status when the thermostat opens (is satisfied) and the stove
will go to a minimum burn and stay there until the thermostat closes (calls for 
heat). When the thermostat closes, the 4 blink status will reset automatically.

Consult your owners’ manual for a description of the 4-blink status. This error 
occurs when the contril board senses the room sensing probe isn’t connected or has
failed. This happens with the thermostat in series, since when the thermostat opens(
is satisfied), there is a loss of continuity in the room-sensing circuit. The 4 
blink status automatically resets when the board recognizes the room-sensing probe
has been reconnected (ie: when the thermostat closes and calls for heat).