Beckett CF2500 manual Typical Burner Sequence of Operation RM7897A Control

Section: Wire the Burner

Typical Burner Sequence of Operation - RM7897A Control

When firing over 20 GPH the CF2500 and CF3500A will be supplied with a flame safeguard control. An airflow switch and low-fire start relay will also be supplied. Consult local, state, and federal codes for burner requirements above 20GPH.

Install the burner and all wiring in accordance with the National Electrical Code and all applicable local codes or requirements.

Wire the burner in compliance with all instructions provided by the appliance manufacturer. Verify operation of all controls in accordance with the appliance manufacturer’s guidelines.

1.Initiate - Power is supplied to the control. The control performs a self-check to ensure proper operation.

2.Standby - the burner is idle waiting for a call for heat. When the call for heat is initiated, the burner will proceed to step 3.

3.Pre-purge- the burner will begin a 60 second pre- purge to clear the combustion chamber. The burner checks the air flow interlock to see if air is being provided. If the air flow is not present the burner will lockout if jumper JR3 is cut or recycle if the jumper is intact.

4.Trial for Ignition - The RM7897A has two trial periods. The first is for light off the second is for main flame establishing. The burner must see flame within 10 seconds if jumper 1 is intact or 4 seconds if jumper 1 is clipped. If the flame is not established, the burner will lockout if jumper 2 is clipped or recycle if the jumper is intact. The burner will then proceed to main flame establishing. If flame is not sensed within 3 seconds the burner will lockout or recycle depending on the status of jumper 2.

5.Run: With a flame established and the control continuing to detect a flame, the burner will operate in the RUN mode until the load demand is satisfied or a limit opens.

a.If terminals RC1 and RC2 are jumpered, the burner operates in the Low-High-Off Mode. The burner starts at Low, goes to High after the flame stabilization period. Flame is extinguished when the load is satisfied or a limit opens, and the burner is sent to post purge.

b.If a high/low control has been wired between terminals RC1 and RC2 the burner starts at Low and is released to go High after the flame stabilization period. It can repeatedly cycle between low and high as necessary to meet load demand until the load is satisfied or a limit opens. The burner is then sent to post purge.

6.Post purge - The control enters a post purge cycle to clear the combustion chamber of gases. Length of the post purge is factory programmed at 15 seconds.

Figure 14 - Typical Burner Sequence of

Operation - RM7897A

1

Initiate

2

Stand by

3

Prepurge

4

Recycle Trial for Lockout

Ignition

5

Run

6

Post Purge

CF2500/CF3500 Burner Manual

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