Vaillant Boiler Heat Exchanger Gasket Seal 0020038679

This Vaillant heat exchanger gasket seal helps maintain a tight seal between the heat exchanger and combustion chamber assembly. If the gasket is worn, heat-cycled, or damaged it can cause poor ignition, combustion leaks, sooting, unusual smells, noisy operation, reduced efficiency, and intermittent boiler lockouts. Replacing it with the correct gasket seal is a reliable fix that restores proper sealing and helps reduce repeat shutdown risk.

Compatibility :

• Ecomax:613 VU126 E-C, 613/2 E VU 126/2-C, 618 VU196 E-C, 618/2E VU186/2-C, 622 VU 246 E-C, 622/2E VU 226/2-C, 635 E VU356-C, 635 VU, 646 VU, 824E VUW 246E-C, 824/2E VUW 246/2-C, 828E VUW 286 E-C, 828/2E VUW 286/2-C, 835E VUW 356-C
• Ecomax Pro: 18 E VU 186-0, 28 E VU 286-0
• Ecotec Exclusive: 832, 835, 838, 843
• Ecotec Plus (System OH): 415, 418, 428, 438
• Ecotec Plus 612: VU 126/3-5, VU 126/3-5 R1, VU 126/5-5, VU 126/5-5 R1, VU 126/5-5 R2, VU 126/5-5 R4, VU 126/5-5 A R4, VU 126/5-5 R6
• Ecotec Plus 615: VU 156/3-5, VU 156/3-5 R1, VU 156/5-5, VU 156/5-5 R1, VU 156/5-5 R2, VU 156/5-5 R4, VU 156/5-5 A R4, VU 156/5-5 R6
• Ecotec Plus 618: VU 186/3-5, VU 186/3-5 R1, VU 186/5-5 (NG), VU 186/5-5 (LPG), VU 186/5-5 R1 (NG), VU 186/5-5 R1 (LPG), VU 186/5-5 R2 (NG), VU 186/5-5 R2 (LPG), VU 186/5-5 R4 (NG), VU 186/5-5 R4 (LPG), VU 186/5-5 A R4 (NG), VU 186/5-5 A R4 (LPG), VU 186/5-5 R6 (NG), VU 186/5-5 R6 (LPG)
• Ecotec Plus 624: VU 246/3-5, VU 246/3-5 R1, VU 246/5-5, VU 246/5-5 R1, VU 246/5-5 R2, VU 246/5-5 R4, VU 246/5-5 A R4, VU 246/5-5 R6
• Ecotec Plus 630: VU 306/3-5, VU 306/3-5 R1, VU 306/5-5 (NG), VU 306/5-5 (LPG), VU 306/5-5 R1 (NG), VU 306/5-5 R1 (LPG), VU 306/5-5 R2 (NG), VU 306/5-5 R2 (LPG), VU306/5-5 R4 (NG), VU 306/5-5 R4 (LPG), VU 306/5-5 A R4 (NG), VU 306/5-5 A R4 (LPG), VU 306/5-5 R6 (NG), VU 306/5-5 R6 (LPG)
• Ecotec Plus 637: VU 376/3-5 R1, VU 376/5-5, VU 376/5-5 R1, VU 376/5-5 R2, VU 376/5-5 R4, VU 376/5-5 A R4, VU 386/5-5 R6
• Ecotec Plus 824: VUW 246/3-5, VUW 246/3-5 R1, VUW 246/3-5 R3, VUW 246/5-5, VUW 246/5-5 R1, VUW 246/5-5 R2, VUW 246/5-5 R4
• Ecotec Plus 825: VUW 256/5-5 R4, VUW 196/5-5 R6
• Ecotec Plus 831: VUW 316/3-5, VUW 316/3-5 R1, VUW 316/3-5 R3, VUW 316/3-5 R5, VUW 316/5-5 (NG), VUW 316/5-5 (LPG), VUW 316/5-5 R1 (NG), VUW 316/5-5 R1 (LPG), VUW 316/5-5 R2 (NG), VUW 316/5-5 R2 (LPG), VUW 316/5-5 R4 (NG), VUW 316/5-5 R4 (LPG)
• Ecotec Plus 832: VUW 326/5-5 R4, VUW 246/5-5 R6 (NG), VUW 246/5-5 R6 (LPG)
• Ecotec Plus 835: VUW 356/5-5 R4, VUW 306/5-5 R6
• Ecotec Plus 837: VUW 376/3-5 R1, VUW 376/3-5 R3, VUW 376/5-5, VUW 376/5-5 R1, VUW 376/5-5 R2, VUW 376/5-5 R4
• Ecotec Plus 838: VUW 386/5-5 R4, VUW 286/5-5 R6
• Ecotec Plus 937: VUI 376/3-5, VUI 376/5-5, VUI 376/5-5 R1, VUI 376/5-5 R2, VUI 376/5-5 R4
• Ecotec Plus 938: VUI 386/5-5 R4, VUI 286/5-5 R6
• Ecotec Pro 22: VU 226/5-3 A R4, VU 226/5-3 R4
• Ecotec Pro 24: VUW 246/3-3 R1, VUW 246/3-3 R2, VUW 246/5-3, VUW 246/5-3 R1, VUW 246/5-3 R2, VUW 246/5-3 R4, VUW 246/5-3 R6
• Ecotec Pro 28: VUW 286/3-3 R1, VUW 286/3-3 R2, VUW 286/5-3 (NG), VUW 286/5-3 (LPG), VUW 286/5-3 R1 (NG), VUW 286/5-3 R1 (LPG), VUW 286/5-3 R2 (NG), VUW 286/5-3 R2 (LPG), VUW 286/5-3 R4 (NG), VUW 286/5-3 R4 (LPG), VUW 286/5-3 R6, VUW 286/5-3 R6 LPG
• Ecotec Pro 30: VUW 306/5-3 R4
• Exclusive: 627 VU 256/5-7
• Sustain: 24 VUW 246/7-2, 28 VUW 286/7-2, 34 VUW 346/7-2
• Ecotec Plus VU GB: 446/5-5 H, 606/5-5 H
• Ecotec VU GB: 466/4-5, 466/4-5 A, 466/4-5 H

Important fitting advice

We recommend that all parts are fitted by a fully qualified Gas Safe registered engineer. If you need help confirming the right part, contact us our team has 10+ years of boiler spares knowledge and friendly chat support to help you quickly.

Delivery

At Boiler Spares Hub, we dispatch orders within 1 working day (Monday-Friday). Orders placed outside working days will be dispatched on the next working day. For delivery options available for this product, please add it to your basket or check our delivery options page.

Returns

We accept 30-day returns. Returns must be in an unopened, sealed box. If we find the item has been used or installation was attempted, we may refuse the return.

Frequently Asked Questions (FAQs)

1. What is the Vaillant Heat Exchanger Gasket Seal 0020038679?
It’s a heat exchanger/burner seal gasket that creates an airtight seal between the combustion/burner assembly and the heat exchanger on compatible Vaillant and Glow-worm boilers.

2. What symptoms indicate the gasket seal may be failing?
Common signs include ignition problems, noisy combustion, unusual smells, sooting, reduced efficiency, unstable flame, and intermittent boiler lockouts.

3. How do I confirm compatibility before ordering?
Check your boiler’s exact model/range (and variant like CXI/HXI/SXI, VUW/VU/VUI) and match it to the compatibility series list for this part number.

4. Can I reuse the old gasket when refitting the heat exchanger?
Not recommended. Once compressed and heat-cycled, gaskets often don’t reseal reliably, which can lead to repeat sealing issues and lockouts.

5. Do I need an engineer to fit this gasket seal?
Yes this is a combustion-seal component. Fitting and safety checks should be carried out by a Gas Safe Register engineer.