Electronic Diverter Valves - any good?

[willdouglas]

PBO 489 Practical Motorboating What's new section included a one-touch electronic diverter valve made by Avant-tech for £299.95.

Has anyone fitted one or had experience of one? I am trying to find out if it's worth the money before shelling out 300 quid.

 

[jeremyshaw]

What did you want to divert? Seems a bit pricey. A standard 3 port domestic heating valve is about £40, so with an inverter you could set it up for a lot less. But if you want to divert a 1.5" black water system that would be another matter (and another thing to go wrong!).

 

[willdouglas]

Thanks for your reply Jeremy.

It's basically a one touch box connected to a bespoke diverter valve that changes from holding tank to sea toilet.

Our boat is to be based at Chiswick on the tidal Thames and so we we will see both sea toilet usage in the estuary and holding tank usage in the marina and on the Upper Thames.

This piece of kit avoids the hassles of removing panels in the heads to get at the standard manual type of valve on the skin fitting.

This gadget does the changeover at the touch of a button. A control panel with LED display shows where the valve is positioned. There is a 12V or 24V version with a standby draw of 0.04A, and 3.3A under load. The manufacturers recommend that the valve is activated when the main power is up and turned on and, once powered up, the diverter runs itself though a port-to-port cycle to keep the valve seals lubricated and preventing siezing.

 

[jeremyshaw]

Hmm, £300 does seem a lot, though as a bespoke piece of kit it is bound to be pricey.

As you doubtless know the manual valves come in at about £40. We have the Jabsco one - not too impressed as the handle broke after a while (it had been in the same position for some months). The Whale one seems a bit beefier though I have not handled it.

I don't know why there needs to be a standby draw for the Avant-Tech unit, as I don't see why it can't be switched off completely when not in use - after all it's only occasional.

The one thing that would worry me about this is that you won't have any feel for an obstruction. In a domestic heating system you can't be pretty sure there won't be one, but in a waste system all kinds of stuff can get put in. I found a bunch of lettuce in mine once - a visiting child obviously didn't want to eat his lettuce so snuck it and flushed it!

Also these valves can get left in one position for months and some calcification can build up, so I'd worry about that a bit.

You've probably thought of things like improving the access, or using a manual valve but rigging up a remote way to turn it off (I did this recently for an isolating valve - bit of tube with a custom cutout on the end).

Honeywell do a 3 port 38mm valve for about £150 which as I said before you could rig up with an inverter. If you have a genset on board (or existing inverter) you might be able to use that instead, though it's 90 degrees rather than Y which would be preferable - though not essential.

All that said, I don't see why the original idea shouldn't work, provided you used it often enough to stop it binding - the principles are simple enough and well proven.

 

[alanwilson]

I thought about this when re-toileting my Nauticat (installation of holding tank plus Lavac toilet): decided to abandon divereter valves altogether due to cost, difficulty of siting such a large object, more joins to leak, something else to go wrong and the inevitability of having it the wrong way.

Much simpler is to pump from toilet to holding tank all the time; then at sea simply pump out to sea when needed.

 

[jeremyshaw]

[ QUOTE ]

Much simpler is to pump from toilet to holding tank all the time; then at sea simply pump out to sea when needed.

[/ QUOTE ]

I would agree with you, but in our boat we've actually gone the other way. The problem we had was that the tank emptied from the bottom. Idea being that you then shut the seacock in port, or open it at sea for a 'pass through'. But we found that it frequently would not empty (settlement of solids blocked the outlet) and increased calcification, so I installed a diverter valve. I note that you talk of pumping out, so I am sure you don't have this problem (though you have to remember to pump I guess). I just wanted to flag up to others the potential issues with 'pass through' holding tanks.

 

[alanwilson]

I had that problem on a previous boat: the holding tank emptied from the bottom & sometimes blocked. The killer was one day in the Dutch inland waterways: to unblock it the crew put the boat on port tack to get the bottom of the tank above water level: I then undid the drain hose, put a saucepan under the outlet & used a screwdriver. Not pleasant. Then the crew tacked...! So - one hand over the hose cos the sea-cock wasn't off (no need, as it was above the waterline - on the previous tack) and the other hand over the tank outlet, screaming at the crew to tack back: they couldn't hear me. It was a very long 10 min before they tacked again.

The cure was simple: insert a length of PVC pipe with a bend into the outlet hole in the bottom of the tank: a reasonably tight fit, but no need to be watertight. It goes up 20cm, then bends back down through 180 degrees (gentle bend to not restrict flow), down to 2cm above the tank bottom.

OK, you never empty the bottom 2cm, but the pipe never blocks since sediment doesn't lie in it. And solids that remain in the bottom of the tank are gradually broken up by the movement of the boat.

Worked for me & better than diverter valve.