Ideal Relay PCB Hi/Low Control 174746

The Ideal 174746 is a relay printed circuit board configured for high/low control, used to switch the burner between its high and low firing rates on Ideal Commercial appliances. It is manufactured by Ideal and belongs to the control electronics group of spares for the Concord ESi CPT range of commercial boilers. The board carries the relay switching that governs staged output, so it sits directly in the firing-rate control path of the appliance.

• The appliance runs only at one firing rate, with no step between high and low output.
• Audible relay chatter or clicking from the control area, with the burner failing to hold a stable rate.
• Intermittent lockout or shutdown shortly after the burner lights.
• The boiler ignores a demand or drops out mid-cycle when the firing rate should change.
• Visible heat damage, scorching or corrosion on the board or its relay contacts.

• Confirm the appliance model and serial number against the compatibility list, as the Concord ESi CPT range uses more than one control board variant.
• Note the alternative number 1780684 when cross-checking against the board already fitted.
• Inspect the existing board and its connectors for heat damage before ordering, since wiring faults can damage a replacement board.
• Work on the control panel should be carried out by a competent engineer with the appliance isolated from the electrical supply.