Question 1

Water pump will not start / blows circuit breaker

Accepted Answer

Check: that the electrical connections, the breaker, the main switch, and the earth link are all sound; whether the motor feels hot (its thermal breaker may just need time to cool before it resets); whether voltage actually reaches the switch (bypass the pressure switch briefly - if the pump then runs, the switch itself has failed); the charging system's own voltage output (+/-10%) and its earthing; whether a circuit or the motor has gone open or shorted to earth, or the wiring is under-sized; and whether the diaphragm assembly has seized or frozen solid.

Question 2

Water pump will not prime / splutters (no discharge, motor runs)

Accepted Answer

Check: whether the filter's clogged with debris; whether there's water in the tank or air trapped in the hot-water side; whether the inlet pipework is drawing in air at a loose connection; whether inlet/outlet plumbing is restricted or kinked; the voltage present while the pump runs (+/-10%); for debris or swelling in the inlet/outlet valves; and for cracks in the pump housing or a loose drive assembly.

Question 3

Water pump will not shut off / runs when tap is closed

Accepted Answer

Check: the pressure-side plumbing (and any valves, or the toilet) for leaks; whether air's trapped on the water-heater side or in the pump head itself; the voltage actually reaching the pump (+/-10%); whether the drive assembly or pump-head screws have worked loose; whether debris or swollen rubber is holding a valve or the built-in check-valve open; and whether the pressure switch itself needs adjusting (see the separate shut-off procedure).

Question 4

Water pump runs noisily or roughly

Accepted Answer

Check: for plumbing that's vibrated loose; whether rigid pipework is carrying the noise; whether the mounting surface is amplifying it; for loose or over-tightened mounting feet; for the three long screws securing the pump head to the motor; and, with the head removed, whether the noise is coming from the motor or the head itself.

Question 5

Water pump cycles rapidly

Accepted Answer

Check: the pressure switch's shut-off adjustment; whether a fitted water purifier is fed via its own separate line; and for overly restrictive plumbing or flow restrictors fitted in taps or shower heads.

Question 6

Water leaks from the pump head or switch

Accepted Answer

Check: for loose screws at the switch or pump head; whether the switch diaphragm has ruptured or is pinched; or whether water inside the drive assembly points to a punctured diaphragm.

Question 7

Water pump cycles rapidly

Accepted Answer

Check the pressure switch shut-off adjustment; ensure a water purifier (if fitted) is on a separate feed line; check for restrictive plumbing or flow restrictors in taps/shower heads.

Question 8

Water pump leaks from the pump head or switch

Accepted Answer

Check for loose screws at the switch or pump head; check whether the switch diaphragm is ruptured or pinched, or punctured (water present in the drive assembly).

Question 9

Water pump not operating (12V system)

Accepted Answer

Possible cause: Switched off at control panel. Switch it on

Question 10

Water pump not operating (12V system)

Accepted Answer

Possible cause: Pressure switch on pump not operating. Refer to dealer

Question 11

Water pump not operating (12V system)

Accepted Answer

Possible cause: Fuse 4 blown. Track down the fault and fit a replacement fuse of the identical rating.

Question 12

Continuous running of water pump

Accepted Answer

Possible cause: No water. Fill tank

Question 13

Continuous running of water pump

Accepted Answer

Possible cause: Major leak. Turn the system off straight away and check it over.

Question 14

Intermittent operation of water pump

Accepted Answer

Possible cause: Minor leak in water system. Check push-fit joints

Question 15

Intermittent operation of water pump

Accepted Answer

Possible cause: Water pump pressure release valve reasserting itself. No action needed - this is part of the pump's normal design

Question 16

Water pump does not operate

Accepted Answer

Possible cause: Fuse 4 blown. Track down the fault and fit a replacement fuse of the identical rating.

Question 17

Water gauge does not operate

Accepted Answer

Possible cause: Probe fault. Refer to dealer (check probe connections)

Question 18

Slow drainage from sink/shower tray

Accepted Answer

Possible cause: Blocked breathers in waste tank. Drop tank and clear breathers

Question 19

Tip-up handbasin slow to drain

Accepted Answer

Possible cause: Blocked drain hole. Remove basin and clear

Question 20

Unsatisfactory operation of water pump

Accepted Answer

Possible cause: Filter blocked. Clean filter

Question 21

Pump feed does not operate (PSU control panel)

Accepted Answer

Possible cause: A fuse has blown. Replace with the correct-rated fuse.

Question 22

Pump feed does not operate (PSU control panel)

Accepted Answer

Possible cause: Pump switched off. Press the tap-symbol pump button on the control panel to switch it back on.

Error Code / Indicator	Symptom / Meaning	Possible Cause	Step-by-Step DIY Fix	Suggested Actions
`N/A`	Water pump will not start / blows circuit breaker	—	Check: that the electrical connections, the breaker, the main switch, and the earth link are all sound; whether the motor feels hot (its thermal breaker may just need time to cool before it resets); whether voltage actually reaches the switch (bypass the pressure switch briefly - if the pump then runs, the switch itself has failed); the charging system's own voltage output (+/-10%) and its earthing; whether a circuit or the motor has gone open or shorted to earth, or the wiring is under-sized; and whether the diaphragm assembly has seized or frozen solid.	DIY Safe
`N/A`	Water pump will not prime / splutters (no discharge, motor runs)	—	Check: whether the filter's clogged with debris; whether there's water in the tank or air trapped in the hot-water side; whether the inlet pipework is drawing in air at a loose connection; whether inlet/outlet plumbing is restricted or kinked; the voltage present while the pump runs (+/-10%); for debris or swelling in the inlet/outlet valves; and for cracks in the pump housing or a loose drive assembly.	DIY Safe
`N/A`	Water pump will not shut off / runs when tap is closed	—	Check: the pressure-side plumbing (and any valves, or the toilet) for leaks; whether air's trapped on the water-heater side or in the pump head itself; the voltage actually reaching the pump (+/-10%); whether the drive assembly or pump-head screws have worked loose; whether debris or swollen rubber is holding a valve or the built-in check-valve open; and whether the pressure switch itself needs adjusting (see the separate shut-off procedure).	DIY Safe
`N/A`	Water pump runs noisily or roughly	—	Check: for plumbing that's vibrated loose; whether rigid pipework is carrying the noise; whether the mounting surface is amplifying it; for loose or over-tightened mounting feet; for the three long screws securing the pump head to the motor; and, with the head removed, whether the noise is coming from the motor or the head itself.	DIY Safe
`N/A`	Water pump cycles rapidly	—	Check: the pressure switch's shut-off adjustment; whether a fitted water purifier is fed via its own separate line; and for overly restrictive plumbing or flow restrictors fitted in taps or shower heads.	DIY Safe
`N/A`	Water leaks from the pump head or switch	—	Check: for loose screws at the switch or pump head; whether the switch diaphragm has ruptured or is pinched; or whether water inside the drive assembly points to a punctured diaphragm.	DIY Safe
`N/A`	Water pump cycles rapidly	—	Check the pressure switch shut-off adjustment; ensure a water purifier (if fitted) is on a separate feed line; check for restrictive plumbing or flow restrictors in taps/shower heads.	DIY Safe
`N/A`	Water pump leaks from the pump head or switch	—	Check for loose screws at the switch or pump head; check whether the switch diaphragm is ruptured or pinched, or punctured (water present in the drive assembly).	DIY Safe
`N/A`	Water pump not operating (12V system)	Switched off at control panel	Switch it on	DIY Safe
`N/A`	Water pump not operating (12V system)	Pressure switch on pump not operating	Refer to dealer	Professional Intervention Required
`N/A`	Water pump not operating (12V system)	Fuse 4 blown	Track down the fault and fit a replacement fuse of the identical rating.	DIY Safe
Recommended partsAffiliate linksView 2 optionsHide Check whether the blown fuse is a standard or a mini blade fuse (mini ones are roughly half the size), then choose the matching kit: This fault doesn't say which fuse rating has blown, only to replace it like-for-like. Both kits cover the common ratings (5A-30A) - match the rating printed on the blown fuse. Standard blade fusesCar Fuse Kit - 60pc Assorted Blade Fuses (5A-30A) with Storage Case and Fuse Puller~£5.994.5★ (1,500+ ratings), sold by KANGRUI, dispatched by Amazon - includes 15A blade fuses plus a puller and storage case View on Amazon → Mini blade fusesNilight 120pc Mini Blade Fuse Assortment (5A-30A, ATM/APM) with Fuse Puller~£5.244.5★ (2,500+ ratings), sold by Amazon - includes 15A mini blade fuses View on Amazon →
`N/A`	Continuous running of water pump	No water	Fill tank	DIY Safe
`N/A`	Continuous running of water pump	Major leak	Turn the system off straight away and check it over.	DIY Safe
`N/A`	Intermittent operation of water pump	Minor leak in water system	Check push-fit joints	DIY Safe
`N/A`	Intermittent operation of water pump	Water pump pressure release valve reasserting itself	No action needed - this is part of the pump's normal design	DIY Safe
`N/A`	Water pump does not operate	Fuse 4 blown	Track down the fault and fit a replacement fuse of the identical rating.	DIY Safe
Recommended partsAffiliate linksView 2 optionsHide Check whether the blown fuse is a standard or a mini blade fuse (mini ones are roughly half the size), then choose the matching kit: This fault doesn't say which fuse rating has blown, only to replace it like-for-like. Both kits cover the common ratings (5A-30A) - match the rating printed on the blown fuse. Standard blade fusesCar Fuse Kit - 60pc Assorted Blade Fuses (5A-30A) with Storage Case and Fuse Puller~£5.994.5★ (1,500+ ratings), sold by KANGRUI, dispatched by Amazon - includes 15A blade fuses plus a puller and storage case View on Amazon → Mini blade fusesNilight 120pc Mini Blade Fuse Assortment (5A-30A, ATM/APM) with Fuse Puller~£5.244.5★ (2,500+ ratings), sold by Amazon - includes 15A mini blade fuses View on Amazon →
`N/A`	Water gauge does not operate	Probe fault	Refer to dealer (check probe connections)	DIY Check / Tech Fallback
`N/A`	Slow drainage from sink/shower tray	Blocked breathers in waste tank	Drop tank and clear breathers	DIY Safe
`N/A`	Tip-up handbasin slow to drain	Blocked drain hole	Remove basin and clear	DIY Safe
`N/A`	Unsatisfactory operation of water pump	Filter blocked	Clean filter	DIY Safe
`N/A`	Pump feed does not operate (PSU control panel)	A fuse has blown	Replace with the correct-rated fuse.	DIY Safe
Recommended partsAffiliate linksView 2 optionsHide Check whether the blown fuse is a standard or a mini blade fuse (mini ones are roughly half the size), then choose the matching kit: This fault doesn't say which fuse rating has blown, only to replace it like-for-like. Both kits cover the common ratings (5A-30A) - match the rating printed on the blown fuse. Standard blade fusesCar Fuse Kit - 60pc Assorted Blade Fuses (5A-30A) with Storage Case and Fuse Puller~£5.994.5★ (1,500+ ratings), sold by KANGRUI, dispatched by Amazon - includes 15A blade fuses plus a puller and storage case View on Amazon → Mini blade fusesNilight 120pc Mini Blade Fuse Assortment (5A-30A, ATM/APM) with Fuse Puller~£5.244.5★ (2,500+ ratings), sold by Amazon - includes 15A mini blade fuses View on Amazon →
`N/A`	Pump feed does not operate (PSU control panel)	Pump switched off	Press the tap-symbol pump button on the control panel to switch it back on.	DIY Safe

Auto-Sleepers Water System

Master Troubleshooting & Diagnostics Matrix

Frequently Asked Questions

Q: How do I winterise the water system before storing the vehicle for winter?