A futures contract is an agreementQuality Lennox Furnace Circuit Board & Timer Parts From Repair Clinic. A Lennox control board replacement can cost $400-$600 if you're having a certified HVAC expert do the job. That's because it's not the simplest part to replace. But it doesn't mean you shouldn't buy your new Lennox furnace motherboard from RepairClinic!Pyrex pattern libraryWorks perfectly as a replacement for my older Lennox board. Came with everything I needed; mount board, standoffs, extra wiring, etc. Great replacement for original Lennox G40UH-36A-070X furnace control board that was shutting off after overheating.