Smart or dumb 12volt waste tank outlet?

[Pudsey Bear]

My cold water drain valve was a real ball ache to access so in it's place I mackled a 22mm motorised valve that's used for central heating systems. They have a rubber ball that's pulled tightly against the aperture with a strong spring so would probably be reliable on a waste outlet.
Operating voltage is 230V so you'd need to power it via your inverter and of course protect the whole thing from road spray if it's going to be under the van.

Salus PMV28 Standard 2 Port Motorised 28mm Valve for Central Heating & Hot Water for sale online | eBay

Find many great new & used options and get the best deals for Salus PMV28 Standard 2 Port Motorised 28mm Valve for Central Heating & Hot Water at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Our van has something like this

https://www.amazon.co.uk/dp/B0CCWX46T9/ref=sspa_dk_detail_1?psc=1&pf_rd_p=84ea1bf1-65a8-4363-b8f5-f0df58cbb686&pf_rd_r=B7CYKW6NJDBHYWY5XD8H&pd_rd_wg=YqyBx&pd_rd_w=ykXeW&content-id=amzn1.sym.84ea1bf1-65a8-4363-b8f5-f0df58cbb686&pd_rd_r=a437f89a-35b2-43f0-8c4c-73494d0ae839&s=diy&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw

with the operating rod extended to the edge of the van for easy access.

That last one is what I meant in my post #8 Merlin, all things are possible but it's be too much work to convert the tank