Because this model is entirely mechanical, adjustments are physical rather than digital. :
The (often branded under Robertshaw as the VC4200 series ) is a mechanical, heavy-duty commercial gas thermostat primarily used for high-capacity cooking equipment like deck ovens, pizza ovens, and convection ranges . Unlike modern residential digital thermostats, this model uses a throttling mechanism to provide precise temperature regulation for gas appliances. Key Specifications & Features Application : Designed for commercial gas-fired equipment.
: If you have a digital Invensys model (like the 9000 series) rather than the mechanical FD, "LO" typically indicates a low battery or that the room temperature is below 30°F. Invensys Thermostat Manual Model Fd
: Features "In" (incoming supply) and "Out" (main burner supply) ports.
: Two side screws allow for manual adjustment of the pilot (P) and bypass (B) functions. Operating & Calibration Instructions Because this model is entirely mechanical, adjustments are
: For digital models, prying the front cover off and removing batteries for 5 minutes often performs a hard reset.
Adjust the pilot flame to a height of approximately 1/2 inch using the adjustment screw (marked 'P'). : Key Specifications & Features Application : Designed for
Push and hold the red button fully in, then light the pilot.