https://hssspares.co.uk/product/vaillant-0020003423/
VAILLANT 0020003423 - PRINTED CIRCUIT BOARD, MAIN - HSS Boiler & Heating Spares
Mar 31, 2026 - VAILLANT 0020003423 PRINTED CIRCUIT BOARD, MAIN. Next Day Shipping | Trade Customer Discounts. Fits
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