Improving Grey waste pipe emptying

I've planned it all out. :cool:

Key Objectives​


  • Retain current manual tap for use when outside.
  • Add electric valve in parallel (not in series) so you can operate it remotely.
  • Switch inside cab wired to 12V supply for convenient control.


🧰 Parts You’ll Need​


  1. 12V Electric Ball Valve (motorhome-safe, corrosion-resistant)
    • E.g., DN25 (1") or DN32 (1¼") depending on pipe diameter
    • Look for a normally closed or auto-return type
    • Plastic or stainless steel body preferred
  2. Y-piece or T-piece connector (for grey waste outlet)
    • Match your hose diameter (usually 28–40mm in Swift motorhomes)
  3. Short lengths of grey waste hose (same diameter as existing one)
  4. 12V momentary or latching switch (for dash control)
    • Toggle or push button, waterproof optional
  5. Inline fuse + wiring (12V rated, 5A fuse usually sufficient)
  6. (Optional) Indicator light to confirm when valve is open
  7. (Optional) Relay for isolating switch from high current load


🛠️ Installation Steps​


1. Install T/Y Junction​


  • Cut the current hose after the manual valve.
  • Insert a T or Y-piece connector.
  • One leg continues to the existing outlet.
  • The other leg will lead to the electric valve.

2. Fit Electric Valve​


  • Connect the electric valve using hose clamps and a short hose.
  • Make sure it's mounted securely and angled for gravity drainage.
  • Ensure the valve is rated for grey water (not fresh water only).

3. Wire to Cab Switch​


  • Run 2-core cable from valve to a switch in the cab.
  • Connect to a 12V fused circuit, preferably ignition-switched.
  • Use a latching switch if you want it to stay open until you switch it off.
  • Optional: Add a relay if valve draws high current.

4. Test Operation​


  • Test valve open/close while grey water is in the tank.
  • Ensure no leaks or backflow to manual outlet.
  • Optionally, install a drain camera or indicator to confirm emptying.


💡 Optional Enhancements​


  • Add a wireless remote switch (some valves come with remotes).
  • Add a float sensor or tank level gauge to automate emptying.
  • Add a valve open/closed LED in cab for feedback.


🔌 Example Electric Valve (for Reference)​


  • [AliExpress / eBay] 12V Electric Motorized Ball Valve (1”, DN25)
  • Brand examples: U.S. Solid, SHURflo-compatible, or no-brand but marine/RV-rated
  • IP65+ rated for outdoor use


🧾 Notes​


  • UK motorhomes often use 28.5mm or 32mm waste pipes.
  • Check your grey tank's exact outlet size before buying parts.
  • Make sure the valve can handle warm soapy water and debris.
  • If space is tight, a solenoid valve may be more compact, but ball valves are more reliable for grey water.
 
Hi All,

I am finding this post both interesting and mesmerising at the same time :) . I have similar problems and whilst they appear to be trivial, when the back or knees play up, and get wet and smelly it is very annoying :mad:

Keep up the good work


Cheers


Boots
 
Can't understand it, why do you have to get on your knees or lie down? Can't you just bend over, turn tap and water runs out?

Edit: Or is it because my van is German and they thought things through?
 
Nabsim said:
Can't understand it, why do you have to get on your knees or lie down? Can't you just bend over, turn tap and water runs out?

Edit: Or is it because my van is German and they thought things through?
Click to expand...

No! The problem is the rise in the expanding pipe from the tank. Its higher than the outlet where it sits. You have to faff on lowering it for it all to drain. It will come out as is when full but not as quick and it will stop at some point. Thats why I was looking for a way of securing it with a quick release so I can just chuck it on the floor and now its morphed into a new set up with Flux Capacitors, remote controls and stuff like that.
 
merl said:
It needs 240v to work it so I have to plug it in but there's no problem with accidentally dumping all our drinking water if a 12v switch gets accidentally switched on😡
Click to expand...

It wouldn't use a lot of power.
If it is 5w (1/2 an amp draw) and is on for 15 minutes it would use less than 1/10th ah.

Could be that a £20 inverter would be up to the job.
 
r4dent said:
It wouldn't use a lot of power.
If it is 5w (1/2 an amp draw) and is on for 15 minutes it would use less than 1/10th ah.

Could be that a £20 inverter would be up to the job.
Click to expand...
It's got a 13a plug that's easily accessible but tucked out of the way, I just plug it into a nearby 13a socket in the kitchen area and turn on the inverter. Wait until the trickling stops and unplug, turn off.
The synchronous motor takes about 10W and not worth worrying about (although I'm sure Barry would give it a decent go), a few minutes and the tank is drained. Hardest job is now shunting the van around on the drive so the outlet is downhill.
 
Last edited:
Pudsey Bear said:
Cut the pipe at the tank, and only use the sink and shower when parked on grass.
Click to expand...

sddefault.jpg
 
barryd said:
I've planned it all out. :cool:

Key Objectives​


  • Retain current manual tap for use when outside.
  • Add electric valve in parallel (not in series) so you can operate it remotely.
  • Switch inside cab wired to 12V supply for convenient control.


🧰 Parts You’ll Need​


  1. 12V Electric Ball Valve(motorhome-safe, corrosion-resistant)
    • E.g., DN25 (1") or DN32 (1¼") depending on pipe diameter
    • Look for a normally closed or auto-return type
    • Plastic or stainless steel body preferred
  2. Y-piece or T-piece connector(for grey waste outlet)
    • Match your hose diameter (usually 28–40mm in Swift motorhomes)
  3. Short lengths of grey waste hose (same diameter as existing one)
  4. 12V momentary or latching switch(for dash control)
    • Toggle or push button, waterproof optional
  5. Inline fuse + wiring (12V rated, 5A fuse usually sufficient)
  6. (Optional) Indicator light to confirm when valve is open
  7. (Optional) Relay for isolating switch from high current load


🛠️ Installation Steps​


1. Install T/Y Junction​


  • Cut the current hose after the manual valve.
  • Insert a T or Y-piece connector.
  • One leg continues to the existing outlet.
  • The other leg will lead to the electric valve.

2. Fit Electric Valve​


  • Connect the electric valve using hose clamps and a short hose.
  • Make sure it's mounted securely and angled for gravity drainage.
  • Ensure the valve is rated for grey water (not fresh water only).

3. Wire to Cab Switch​


  • Run 2-core cable from valve to a switch in the cab.
  • Connect to a 12V fused circuit, preferably ignition-switched.
  • Use a latching switch if you want it to stay open until you switch it off.
  • Optional: Add a relay if valve draws high current.

4. Test Operation​


  • Test valve open/close while grey water is in the tank.
  • Ensure no leaks or backflow to manual outlet.
  • Optionally, install a drain camera or indicator to confirm emptying.


💡 Optional Enhancements​


  • Add a wireless remote switch (some valves come with remotes).
  • Add a float sensor or tank level gauge to automate emptying.
  • Add a valve open/closed LED in cab for feedback.


🔌 Example Electric Valve (for Reference)​


  • [AliExpress / eBay] 12V Electric Motorized Ball Valve (1”, DN25)
  • Brand examples: U.S. Solid, SHURflo-compatible, or no-brand but marine/RV-rated
  • IP65+ rated for outdoor use


🧾 Notes​


  • UK motorhomes often use 28.5mm or 32mm waste pipes.
  • Check your grey tank's exact outlet size before buying parts.
  • Make sure the valve can handle warm soapy water and debris.
  • If space is tight, a solenoid valve may be more compact, but ball valves are more reliable for grey water.
Click to expand...
Is this the AI response, what software are you using, it's surprisingly accurate (Sorry this is a serious question 😀)
 
yeoblade said:
Is this the AI response, what software are you using, it's surprisingly accurate (Sorry this is a serious question 😀)
Click to expand...

Just ChatGPT. Have you not used it? Its brilliant. Its not always right but you basically sit and have a conversation with it. When I Was trying to get Autoroute sorted I couldn't remember all the steps you need to do to make it work but it knew them all. Best if you sign in then it remembers all your chats down the left hand side.

 
Am I understanding ChatGPT correctly?

"
  • Cut the current hose after the manual valve.
  • Insert a T or Y-piece connector.
  • One leg continues to the existing outlet.
  • The other leg will lead to the electric valve."
It seems to me that the manual valve would have to be open for water to reach the electric valve. If one leaves the manual valve open, water drains from the existing outlet and the electric valve is redundant. Surely the T- or Y-piece should be before the manual valve, or am I missing something?
 
TJBi said:
Am I understanding ChatGPT correctly?

"
  • Cut the current hose after the manual valve.
  • Insert a T or Y-piece connector.
  • One leg continues to the existing outlet.
  • The other leg will lead to the electric valve."
It seems to me that the manual valve would have to be open for water to reach the electric valve. If one leaves the manual valve open, water drains from the existing outlet and the electric valve is redundant. Surely the T- or Y-piece should be before the manual valve, or am I missing something?
Click to expand...

Dunno. I never actually read its response. :ROFLMAO:
 
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