The Thetford C402C and C403L are different versions of the C400 cassette-toilet family. The flush hardware, electrical controls, reed switches and some body fittings differ. This guide identifies the original Thetford parts by their numbered factory callouts and shows matching UsedRVParts catalog products where an exact model application is supported.
C402C pump versus C403L water valve
C402C flush-water circuit
C403L pressurized-water circuit
Original C402C/C403L 16-callout parts reference
The following numbers follow Thetford's revised November 2025 C402C/C403L parts sheet. Shared callout numbers can have different part numbers for each model; compare the model badge before ordering.
| Callout | Applies to | Factory number | Component |
|---|---|---|---|
| 1 | Both | 5181462 | Seat and cover (replaces 32309) |
| 2 | C402C | 29027 | 12V flush pump (replaces 33368) |
| 3 | Both | 5180362 | Handle (replaces 51803) |
| 4 | Both | 51802 | Handle shaft |
| 5 | C403L | 16833 | Vacuum breaker |
| 6 | C403L | 23709 | Electric water valve, hose nut and barb |
| 7 | C402C / C403L | 5181062 / 5181262 | Different model-specific control panels |
| 8 | C402C / C403L | 32321 / 32314 | Different control-panel overlays |
| 9 | C403L | 20106 | Relay |
| 10 | Both | 32319 | Wire harness |
| 11 | Both | 32311 | Wall seal |
| 12 | Both | 16451 | 3A fuse (replaces 33342) |
| 13 | C402C / C403L | 3231662 / 3231762 | Different model-specific reed switches |
| 14 | C402C | 3231506 | Water-fill funnel with cap |
| 15 | C403L | 32324 | Vent hose and seal |
| 16 | C402C / C403L | 3243462 / 3243362 | Different kicking plates with clips |
Thetford identifies earlier numbers 33368, 32320 and 32313 as superseded by 29027, 5181062 and 5181262 respectively. Distributor numbers such as 49989, 50020 and 50040 are presented in the product listings below; a model-specific catalog listing does not establish interchangeability with every factory revision.
Matching C402C products in UsedRVParts
These exact catalog records are identified for the C402C model. Check each listing for current condition and availability. Viewing and pickup, where offered, is by appointment in Kelowna.
C403L owners: The 50275 single-button control-panel listing is also available in this store, but its equivalence to the current factory 5181262 control panel has not been confirmed here. Match the original part marking and connection before choosing a replacement.
Original Thetford exploded diagram
View the C402C/C403L original manufacturer exploded diagram and parts list (PDF). Use this reference to confirm all 16 callout locations and the correct revision for your toilet.