Vaillant ecoTEC Exclusive 843 Main Heat Exchanger – Refurbished | Part No. 0020233504

The main heat exchanger is a critical and high-value component in the Vaillant ecoTEC Exclusive 843, responsible for transferring heat from the burner to the central heating and hot water system. When it fails, heating output drops, efficiency suffers, and the boiler may lock out entirely. The Vaillant ecoTEC Exclusive 843 Main Heat Exchanger (Part No. 0020233504) is a professionally refurbished genuine Vaillant replacement that restores full performance to this premium large-output boiler.

This is a fully refurbished original Vaillant part, professionally cleaned, inspected, and tested for functionality before dispatch. It is specifically designed for the Vaillant ecoTEC Exclusive 843 VUW 436/5-7 (H-GB) model. Only 1 unit remaining — order promptly.

Compatible Boiler

Key Features

• Vaillant part number 0020233504 — direct OEM replacement for ecoTEC Exclusive 843 VUW 436/5-7
• Professionally refurbished: cleaned, inspected, and fully tested before dispatch
• Restores efficient heat transfer and resolves heating output failure
• Free next-day delivery available
• Only 1 left in stock — limited availability
• 12-month warranty included

Note: Please confirm that part number 0020233504 and model code VUW 436/5-7 match your boiler before ordering.

Delivery & Returns

Orders placed before 1:00 PM (Monday–Friday) are dispatched the same working day. Standard and next-day delivery options available at checkout. Next-day orders placed on Fridays arrive Monday — select Saturday delivery at checkout for weekend delivery. Returns accepted within 30 days if unused and in original packaging.

Note: Installation must be carried out by a Gas Safe registered engineer.