Question 1

Odor and moisture problems due to insfficient liquid drainage

Accepted Answer

Possible cause: Sharp bends, kinks, or improper slope in the drain hose. Route the drain hose without sharp bends or kinks, ensure proper downward slope using the hose gradient clamp, and make sure only liquids enter the front funnel area.

Question 2

Level indication failure or error in tank status reporting

Accepted Answer

Possible cause: Connection cable pinched during separation cassette insertion. Route the level indication cable securely along the housing to the rear insertion side so it does not get pinched, and ensure the magnetic connector is correctly plugged into the cassette port.

Question 3

Separation cassette does not snap securely into place

Accepted Answer

Possible cause: Locking part misaligned or locking pin missing from the base plate. Line the locking part up with the 6.5mm drill hole (63mm from the base plate's front edge) and push the locking pin in from underneath.

Question 4

Toilet is clogged

Accepted Answer

Possible cause: Use of conventional toilet paper. Use quickly soluble toilet paper (Dometic COMFORT CARE recommended).

Question 5

Unpleasant smells or poor waste decomposition

Accepted Answer

Possible cause: Missing or improper sanitary additives in the cassette tank. Use sanitary additives in the cassette tank (Dometic POWER CARE TABS or GREEN CARE TABS recommended) following manufacturer instructions.

Question 6

Water pipes or tanks frozen during winter

Accepted Answer

Possible cause: Toilet and cassette tank operated in sub-zero/frost areas without draining. Empty the cassette tank, fresh water tank, and all water pipes if operating in areas prone to freezing. Do not use antifreeze.

Question 7

Toilet clogged

Accepted Answer

Possible cause: Use of conventional non-soluble toilet paper. Use quickly soluble toilet paper (Dometic COMFORT CARE recommended).

Question 8

Water pipes or tanks frozen / winter operation failure

Accepted Answer

Possible cause: Sub-zero temperatures in the toilet or cassette tank area. Ensure the area is frost-free. If freezing is possible, completely empty the cassette tank, fresh water tank, and all water pipes.

Question 9

Toilet clogging

Accepted Answer

Possible cause: Use of conventional non-soluble toilet paper. Use quickly soluble toilet paper such as Dometic COMFORT CARE

Question 10

Unpleasant odors / slow waste breakdown

Accepted Answer

Possible cause: Inadequate or missing sanitary additives in the cassette tank. Use recommended additives such as Dometic POWER CARE TABS or GREEN CARE TABS following manufacturer instructions

Question 11

Water pipes or components freezing during winter storage

Accepted Answer

Possible cause: Residual water remaining in lines or tanks in sub-zero frost environments. Empty cassette tank, fresh water tank, and completely flush all water-carrying pipes using the flush button until completely empty

Question 12

Unpleasant smells or poor waste decomposition in the cassette tank

Accepted Answer

Possible cause: Lack of proper sanitary additives or incorrect dosage. Use sanitary additives (Dometic POWER CARE TABS or Dometic GREEN CARE TABS) following manufacturer instructions

Question 13

Water pipes or components frozen during winter operation

Accepted Answer

Possible cause: Freezing temperatures in unheated areas. Ensure toilet and cassette tank are used in frost-free areas; otherwise, completely empty cassette tank, fresh water tank, and all water pipes

Question 14

Stiff mechanical movement or leaking seals

Accepted Answer

Possible cause: Lack of lubrication and build-up of residue on seals and moving parts. Clean and grease all seals and moving parts monthly or after every 3 to 5 emptyings using silicone-based grease or spray (OKS-1110 grease or OKS-1111 silicone grease recommended)

Dometic CT4000 Series

Technical Specifications

Master Troubleshooting & Diagnostics Matrix

Error Code / Indicator	Symptom / Meaning	Possible Cause	Step-by-Step DIY Fix	Suggested Actions
`N/A`	Odor and moisture problems due to insfficient liquid drainage	Sharp bends, kinks, or improper slope in the drain hose	Route the drain hose without sharp bends or kinks, ensure proper downward slope using the hose gradient clamp, and make sure only liquids enter the front funnel area.	DIY Safe
`N/A`	Level indication failure or error in tank status reporting	Connection cable pinched during separation cassette insertion	Route the level indication cable securely along the housing to the rear insertion side so it does not get pinched, and ensure the magnetic connector is correctly plugged into the cassette port.	DIY Safe
`N/A`	Separation cassette does not snap securely into place	Locking part misaligned or locking pin missing from the base plate	Line the locking part up with the 6.5mm drill hole (63mm from the base plate's front edge) and push the locking pin in from underneath.	DIY Safe
`N/A`	Toilet is clogged	Use of conventional toilet paper	Use quickly soluble toilet paper (Dometic COMFORT CARE recommended).	DIY Safe
`N/A`	Unpleasant smells or poor waste decomposition	Missing or improper sanitary additives in the cassette tank	Use sanitary additives in the cassette tank (Dometic POWER CARE TABS or GREEN CARE TABS recommended) following manufacturer instructions.	DIY Safe
`N/A`	Water pipes or tanks frozen during winter	Toilet and cassette tank operated in sub-zero/frost areas without draining	Empty the cassette tank, fresh water tank, and all water pipes if operating in areas prone to freezing. Do not use antifreeze.	DIY Safe
`N/A`	Toilet clogged	Use of conventional non-soluble toilet paper	Use quickly soluble toilet paper (Dometic COMFORT CARE recommended).	DIY Safe
`N/A`	Water pipes or tanks frozen / winter operation failure	Sub-zero temperatures in the toilet or cassette tank area	Ensure the area is frost-free. If freezing is possible, completely empty the cassette tank, fresh water tank, and all water pipes.	DIY Safe
`N/A`	Toilet clogging	Use of conventional non-soluble toilet paper	Use quickly soluble toilet paper such as Dometic COMFORT CARE	DIY Safe
`N/A`	Unpleasant odors / slow waste breakdown	Inadequate or missing sanitary additives in the cassette tank	Use recommended additives such as Dometic POWER CARE TABS or GREEN CARE TABS following manufacturer instructions	DIY Safe
`N/A`	Water pipes or components freezing during winter storage	Residual water remaining in lines or tanks in sub-zero frost environments	Empty cassette tank, fresh water tank, and completely flush all water-carrying pipes using the flush button until completely empty	DIY Safe
`N/A`	Unpleasant smells or poor waste decomposition in the cassette tank	Lack of proper sanitary additives or incorrect dosage	Use sanitary additives (Dometic POWER CARE TABS or Dometic GREEN CARE TABS) following manufacturer instructions	DIY Safe
`N/A`	Water pipes or components frozen during winter operation	Freezing temperatures in unheated areas	Ensure toilet and cassette tank are used in frost-free areas; otherwise, completely empty cassette tank, fresh water tank, and all water pipes	DIY Safe
`N/A`	Stiff mechanical movement or leaking seals	Lack of lubrication and build-up of residue on seals and moving parts	Clean and grease all seals and moving parts monthly or after every 3 to 5 emptyings using silicone-based grease or spray (OKS-1110 grease or OKS-1111 silicone grease recommended)	DIY Safe