Operator`s manual

PUREHEAT DIESEL BURNER CONTROL

SEQUENCE OF OPERATION AND LOCKOUT

NORMAL SEQUENCE OF OPERATION:

Assuming a normal power up has been completed per Section 2 of this manual, the BURNER Switch is turned ON, the In-Line

Fuel Heater is energized and begins to warm the fuel in the Nozzle Assembly Tube. With a demand for heat, output contacts 14

& 15 of the Temperature Control (TC) will close completing a circuit from L1 to the Burner Control Relay Coil (CR-2). Burner

Control Relay (CR-2) normally open contacts 6 - 8 will CLOSE completing a circuit between 3T & T of the burner control.

The Burner Control initiates a 5 second self diagnostic test followed by a non-adjustable 15 second valve on-delay period called

Pre-purge. During the Pre-purge cycle, both the Ignition Transformer and Burner Blower Motor are energized but fuel is not

allowed to flow past the Fuel Shut-off Valve. Once the pre-purge cycle is complete, the Fuel Shut-off Valve Solenoid Coil is

energized by the Burner Control and fuel flow is initiated to the Burner Nozzle. Once fuel flow has begun, a 10 second trial for

ignition period begins. During trial for ignition, the Ignition Transformer remains energized for an additional 10 seconds, this is

known as ignition carryover. Once flame is established and proven by a Cad Cell resistance value of more than 300 but less

than 1600 Ohms, the Ignition and the ten second trial for ignition time has elapsed, the Ignition Transformer is de-energized for

the duration of the heating cycle. Once the demand for heat has been satisfied, output contacts 14 & 15 of the TC OPEN

breaking the circuit to Burner Control Relay Coil CR-2. The now de-energized relay will OPEN Relay CR-2 contacts 6 - 8

breaking the circuit at 3T to T of the Burner Control. The Burner Control will shut off the fuel supply to the burner nozzle by de-

energizing the Fuel Shut-off Valve Solenoid coil. The Burner Blower Motor will continue to run for 15 seconds (post-purge

cycle). The amount of time allowed for pre-purge depends on the Off-delay Dip Switch setting. Ground Heaters, Inc.

recommends the factory setting of 15 seconds off-delay. Several delay settings are available as detailed on the front of the

burner control.

BURNER FAULT:

If the Cad Cell senses an absent or unstable flame at any time during the heating cycle, the Burner Control immediately shuts

down all Burner functions and enters one of three protective modes (BURNER FAULT). BURNER FAULT is identified by the

Diagnostic Light (see photo below) and indicated by illuminating the BURNER FAULT Light (main control panel) simultaneously.

The three BURNER FAULT or Lockout modes are described in detail below.

1. RECYCLE MODE

The DIAGNOSTIC Light will flash in two second intervals while attempting three automatic restarts. If the flame fails after three

successive attempts, the control will enter Lockout Mode.

2. LOCKOUT MODE

The DIAGNOSTIC Light will flash in ½ second intervals. The RESET button must be momentarily pressed to clear the Lockout

and attempt a Burner restart. After the third attempt to manually clear the Lockout mode, the Burner Control will begin

Restricted Lockout Mode.

3. RESTRICTED LOCKOUT MODE

The DIAGNOSTIC Light will flash in ½ second intervals. The RESET button must be pressed and held until the DIAGNOSTIC

Light comes on momentarily and then goes out. The Burner Control will return to Restricted Lockout Mode with each flame

failure until one successful heating cycle has occurred.

DIAGNOSTIC LIGHT

RESET BUTTON

OFF DELAY DIP

SWITCHES

ALARM

(BURNER FAULT)

CONNECTIONS

V. 2, Rev. 09/01/06

A - 12