A 275V varistor is the standard surge clamp on a heater board that runs from 230 V European mains, and Walsin Technology (Walsin) lists 17 of them, 430 V varistor voltage, from 5 mm to 53 mm; 6 fall in the 7 to 14 mm range most heaters use. Venatech is Walsin’s authorised distributor in Hong Kong.
Venatech Limited, an authorised Walsin distributor in Hong Kong, wrote this for an appliance engineer or buyer in Ningbo or Cixi, China, who is protecting the control board of a fan heater, oil radiator or convector sold into the European Union. We parsed Walsin’s varistor export, Walsin_MOV_ALL.xlsx (379 rows), and our stock list as at 23 September 2026. Every part number is real, and the market statement names its source and the day we fetched it.
What did People’s Daily report about Cixi’s heater exports?
A third of China’s heaters, and a growing EU share. People’s Daily Online reported on 11 February 2026 that Cixi’s heating appliance exports reached 3.32 billion yuan in January to November 2025, that exports to the EU were 1.28 billion yuan, up 8.4 percent, and that Cixi accounts for nearly one third of China’s heater exports.
The same report says Zhejiang Jiuyou Electric Appliance produced 300,000 units in 2025, up nearly 30 percent on 2024, and that a Cixi maker can take a new heater model from design to rollout in under two months. Those are the paper’s figures, not ours, and we say nothing about what any named maker buys. For a board designer, a two-month cycle into a 230 V European market means the surge clamp has to be chosen right the first time.
Why does a 230 V heater board use a 275 Vac varistor?
Because 275 Vac sits just above the mains tolerance band. European mains is nominally 230 V with a tolerance that takes it toward 253 V, so the usual metal oxide varistor is the 275 Vac class with a 430 V varistor voltage, and Walsin lists 17 part numbers at exactly that rating in our count of Walsin_MOV_ALL.xlsx.
A varistor rated too low conducts on a high-mains day and ages; one rated too high lets more of a surge through to the triac and the controller. Walsin brackets 275 Vac with 17 parts each at 250 Vac, 300 Vac and 320 Vac, so a designer who wants extra margin can step up one rung without changing family. Our guide to how to choose an MOV varistor walks through the selection, and the MOV voltage ladder shows where the steps sit.
Which Walsin 275 Vac varistors fit a 7 to 14 mm heater footprint?
Six do. We filtered the 17 Walsin 275 Vac varistors to the 7, 10 and 14 mm discs that heater control boards typically carry and found 6 part numbers in two series, with peak current ratings from 1,200 A to 8,000 A in the export.
| Walsin part | Series | Disc size | Varistor voltage | Peak current | Match / mismatch with a 275 Vac, 10 mm brief | Your incumbent |
|---|---|---|---|---|---|---|
SR431K10D |
Standard (D) | 10 mm | 430 V | 2,500 A | Match | |
SR431K10E |
Super High Energy (V) | 10 mm | 430 V | 4,000 A | Match, higher surge rating | |
SR431K14D |
Standard (D) | 14 mm | 430 V | 4,500 A | Mismatch: larger disc, more surge | |
SR431K14E |
Super High Energy (V) | 14 mm | 430 V | 8,000 A | Mismatch: larger disc, most surge | |
SR431K07D |
Standard (D) | 7 mm | 430 V | 1,200 A | Mismatch: smaller disc, less surge | |
SR431K07E |
High Energy (E) | 7 mm | 430 V | 1,750 A | Mismatch: smaller disc, less surge |
All six list a 10 percent varistor-voltage tolerance. The mismatches are footprint and surge-rating differences, not voltage ones: a 14 mm disc will not drop into a 10 mm hole pattern, and a 7 mm disc takes a smaller surge. Confirm against both datasheets and test against the surge level your EU test house applies.
How do the Walsin varistor series differ for a heater maker in Cixi?
By surge energy at a given size. At 10 mm and 275 Vac, our count shows the Standard D series rated 2,500 A and the Super High Energy V series 4,000 A; across the whole 379-part export, Walsin spreads its varistors over D, E, V and Industrial series from 5 mm to 53 mm.
For a heater, the D series is the usual starting point. The V series earns its place where a product must pass a harsher surge level without moving to a bigger disc, and the E series adds a 7 mm option with a higher rating than the D part. The Industrial discs, 32 mm to 53 mm with ratings to 80,000 A, belong in panels, not heaters. Our note on D, E, V and Industrial series selection covers the trade-off, and the varistor range page lists all of them.
How does Venatech supply Walsin 275 Vac varistors to Ningbo and Cixi?
From Hong Kong, through our authorised Walsin channel. The 17 Walsin 275 Vac varistors are quoted to order: request a quote and we source them through our authorised Walsin channel, in small lots for a new model or in production quantities.
Ningbo and Cixi are a short logistics step from Hong Kong. We give no lead-time or stock promise, and the ready-stock list is a dated snapshot as at 23 September 2026, never live-synced. Safety approvals for a varistor sit with Walsin’s own documents for the exact part number; ask us for them. We hold no ISO 9001 or IATF 16949 certificate of our own and give no customs or legal advice; confirm EU compliance questions with your compliance team.
How Venatech helps: how can a Cixi heater team cross its varistors?
In one paste. VenaMatch decodes 18 manufacturers’ part numbers and crosses 800,000+ parts to Walsin, marking each field as a match or a mismatch, so a Cixi team can check its 14D431K or 10D431K style parts against Walsin’s 17 275 Vac varistors in seconds.
Use the cross-reference tool or upload the BOM for the whole control board. Venatech is Walsin’s authorised distributor in Hong Kong; Stackpole and Viking are lines we supply. Ask for a quote through the site and we reply from Hong Kong.
The short version
Cixi exported 3.32 billion yuan of heating appliances in January to November 2025, a third of China’s heater exports, per People’s Daily. For the 230 V surge clamp on those boards, we counted 17 Walsin 275 Vac varistors from 5 to 53 mm; 6 fall in the 7 to 14 mm heater range, with peak ratings from 1,200 A to 8,000 A.
Send us your varistor line with the disc size and the surge level your test house applies, and we will return the Walsin crosses with every field difference marked. Is your heater’s varistor sized for the surge test, or for the footprint?
Related reading
- How to choose an MOV varistor
- The MOV voltage ladder
- MOV series selection: D, E, V and Industrial
- VenaMatch cross-reference tool and ready-stock snapshot
Last reviewed 11 Nov 2026.
Sources
Fetched 11 November 2026.
- People’s Daily Online, Chinese heating appliances gain global traction amid seasonal demand, 11 February 2026: https://en.people.cn/n3/2026/0211/c98649-20424868.html
- Walsin varistor parametric export, Walsin_MOV_ALL.xlsx, and Venatech stock snapshot as at 23 September 2026, both re-measured by Venatech on 11 November 2026.
Frequently asked questions
Which varistor should a 230 V heater board in Cixi, China use?
The usual choice is a 275 Vac metal oxide varistor with a 430 volt varistor voltage. Walsin lists 17 at that rating, and SR431K10D and SR431K10E fit a 10 millimetre footprint. Venatech, Walsin’s authorised distributor in Hong Kong, quotes all of them.
What is the difference between SR431K10D and SR431K10E?
Both are 10 millimetre, 275 Vac, 430 volt Walsin varistors. SR431K10D is the Standard D series with a 2,500 ampere peak current in the export; SR431K10E is the Super High Energy V series with 4,000 amperes. Confirm against the datasheets.
Does Walsin make 300 Vac or 320 Vac varistors for extra margin?
Yes. Our count shows 17 Walsin part numbers each at 250, 275, 300 and 320 Vac, so a heater designer can step up one rung, for example to SR471K10D at 300 Vac, without changing series or disc size.
What did People’s Daily report about Cixi heater exports?
On 11 February 2026 it reported Cixi heating appliance exports of 3.32 billion yuan in January to November 2025, EU exports of 1.28 billion yuan, up 8.4 percent, and a share of nearly one third of China’s heater exports.
Does Venatech hold Walsin varistors in Hong Kong stock?
Walsin varistors are quoted to order: request a quote and we source them through our authorised Walsin channel. The ready-stock page is a snapshot dated 23 September 2026, and we give no stock or lead-time promise.
Can Venatech cross a TDK, Littelfuse or Bourns varistor to Walsin?
VenaMatch decodes 18 manufacturers’ part numbers and crosses 800,000+ parts to Walsin, with each field marked match or mismatch. Paste the part number on the cross-reference page and confirm the surge rating against both datasheets.