Thetford 34122
Vacuum Breaker
Thetford 34122 is the vacuum breaker for the Aqua-Magic Residence and Aqua-Magic Style II and Aqua-Magic Style Lite and Aqua-Magic Style Plus. The anti-siphon device on the water supply that stops water being drawn back out of the toilet into the fresh water line. Thetford lists it for Aqua-Magic Residence, Aqua-Magic Style II, Aqua-Magic Style Lite and Aqua-Magic Style Plus. It is item 3 and 4 depending on the list.
Which models this fits
Aqua-Magic Residence
Verified against Thetford Parts List, Aqua-Magic Residence (Rev. D).
Item 3 on this parts list.
Aqua-Magic Style II
Verified against Thetford Parts List, Aqua-Magic Style II.
Item 3 on this parts list.
Aqua-Magic Style Lite
Verified against Thetford Parts List, Aqua-Magic Style Lite (Rev. D).
Item 4 on this parts list.
Aqua-Magic Style Plus
Verified against Thetford Parts List, Aqua-Magic Style Plus.
Item 3 on this parts list.
What this does NOT fit
Cassette C200S-CS. Thetford's Cassette C200S-CS parts list assigns 16833 to this position, not 34122.
Cassette C223CS. Thetford's Cassette C223CS parts list assigns 16833 to this position, not 34122.
Cassette C223S. Thetford's Cassette C223S parts list assigns 16833 to this position, not 34122.
Cassette C224CW. Thetford's Cassette C224CW parts list assigns 16833 to this position, not 34122.
Cassette402C.403L. Thetford's Cassette402C.403L parts list assigns 16833 to this position, not 34122.
Commonly confused with this
16833 is the vacuum breaker listed for Cassette C200S-CS, Cassette C223CS, Cassette C223S, Cassette C224CW and Cassette402C.403L. 34122 is listed for Aqua-Magic Residence, Aqua-Magic Style II, Aqua-Magic Style Lite and Aqua-Magic Style Plus. They appear on separate Thetford parts lists.
How to tell which one you have
Find item 3 or 4 on your model’s parts diagram — that callout is this part. Check the model on the data plate reads Aqua-Magic Residence, Aqua-Magic Style II, Aqua-Magic Style Lite or Aqua-Magic Style Plus.
Is this part still current?
Yes. Thetford still lists 34122 on its current parts list.
Also worth having before you start
- Thetford seal lube and conditioner
A new seal lasts longer if it is kept conditioned. Thetford makes this for its own toilets, so it is the maintenance product matched to the part you are fitting.
These are supplies, not replacement parts. We have not matched them to your model, because they do not need to fit anything.
Check this before you order
- Confirm your toilet is a Aqua-Magic Residence, Aqua-Magic Style II, Aqua-Magic Style Lite or a Aqua-Magic Style Plus.
- If it is a Cassette C200S-CS, Cassette C223CS, Cassette C223S, Cassette C224CW or a Cassette402C.403L, order 16833 instead.
- Ignore listing titles that claim one part covers several models unless the manufacturer's parts lists agree.
Current marketplace inventory
Listings from eBay
We verified the part above from manufacturer documents. The listings below are current eBay inventory, and eBay sellers set their own titles, prices and shipping.
Checking current eBay inventory…
Camper Replacement Parts is not the seller. Price, shipping, stock and item condition are set by the eBay seller and can change at any time. We may earn a commission if you buy through these links.
Where our information comes from
We work from the manufacturer’s own documents. We have not installed this part and we do not test parts in a shop.
- Thetford Parts List, Aqua-Magic Residence (Rev. D). Published by Thetford.
- Thetford Parts List, Aqua-Magic Style II. Published by Thetford.
- Thetford Parts List, Aqua-Magic Style Lite (Rev. D). Published by Thetford.
- Thetford Parts List, Aqua-Magic Style Plus. Published by Thetford.
- Thetford Parts List, Cassette C200S-CS (Rev. D). Published by Thetford.
- Thetford Parts List, Cassette C223CS (Rev. D). Published by Thetford.
- Thetford Parts List, Cassette C223S (Rev. D). Published by Thetford.
- Thetford Parts List, Cassette C224CW (Rev. E). Published by Thetford.
- Thetford Parts List, Cassette402C.403L (Rev. D). Published by Thetford.
Last checked 2026-08-29.