Jabsco Lock n Twist. What is it?

[NPMR]

I have the heads in bits at the moment and will be 'servicing' the pump shortly.

Looking at Jabsco (and other sites) for a service kit, I am also offered an alternative pump, rather than a service kit. That pump is a "Lock n Twist" one.

But having scoured the Jabsco site and others too, I can find no words that tell me a) what is different about it and b) why I'd want it?

Anyone know?

PS appalling marketing, if you have to work hard to find out why you'd bother!

 

[rob2]

The new pump handle twists through 90 deg when "parked" so as to lock the valves closed, preventing back flow and syphoning.

Rob.

 

[Vara]

I fitted one of those, my understanding is that the twist and lock pushes a bung into a position where it blocks the outlet port so that no liquid can flow back through the pump, a common fault when the joker valve is compromised by debris or scale.

Seems to work well.

Great care must be taken when fitting as screws go into soft plastic and can be cross threaded or stripped.

 

[NPMR]

Thanks for that Rob2.

The replacement pump is a bit more than double the cost of the service kit (at about £57 from what I can see) but as we've never had any problems with back flow or siphoning and it is an absolute rule on our boat, on pain of a big strop from the skipper if flouted, that the seacocks are closed at all times except when pumping, I guess the extra cost is not worthwhile.

So a standard service kit it is, then.

Thanks again.

 

[VicS]

It only plugs the outlet I believe.
No change to the way the inlet works , but that should have a vented antisyphon loop, replacing the short hose normally supplied, fitted between pump and bowl if the toilet is near or below the heeled water line.

It reduces/eliminates the need for a vented loop ( which might spray effluent over you if it malfunctioned) in the outlet.

 

[Tranona]

Keep a complete pump as a spare if you think you might have trouble later on. Much easier just to swap pumps than take a pump apart in a hurry.

 

[Cloven]

Thanks for that Rob2.

The replacement pump is a bit more than double the cost of the service kit (at about £57 from what I can see) but as we've never had any problems with back flow or siphoning and it is an absolute rule on our boat, on pain of a big strop from the skipper if flouted, that the seacocks are closed at all times except when pumping, I guess the extra cost is not worthwhile.

So a standard service kit it is, then.

Thanks again.

Not sure where you are getting your quote from but you can get a complete Twist n Lock pump assembly for under £50 - just do a Google for Jabsco Twist n Lock Pump.

There will come a point at which the service kit just does not do the job. I got to that point a couple of years ago and decided to replace the pump with the Twist n' Lock unit which, at the time, cost more like £70. However, in the end, it worked out almost as cheap to buy a complete new toilet with the Twist n' Lock pump fully installed. Cost was less than £100 (and still is) for the whole thing and as the seat hinges were getting a bit dicy, made sense.

 

[Hoolie]

It's a typical Jabsco half design. I fitted one a few years ago and within 18 months it had badly distorted the outlet flap valve so that it would not seal at all. My suggestion is to only lock the valve when absolutely necessary, otherwise you'll be forever having to buy new valves for the pump.

 

[RupertW]

Not convinced by them as I've inherited 2 which both let outlet waste back into the bowl if left for a few hours. Although the short-term answer is to keep flushing until there's nothing but seawater in the pipe up to the holding tank, this does mean that the holding tank fills far more quickly than required, so have to up anchor sooner than wanted when staying a day or two somewhere.

I wonder if the valves are distorted but not sure how to tell.

 

[Hoolie]

... ...
I wonder if the valves are distorted but not sure how to tell.

Take the pump off at the base and look at the centre of the flap valve. It should be flat and seal to stop backflow to the bowl. If it's bowed (depressed in the centre by the locking mechanism) then it is knackered and won't seal properly.

 

[prv]

Not convinced by them as I've inherited 2 which both let outlet waste back into the bowl if left for a few hours. Although the short-term answer is to keep flushing until there's nothing but seawater in the pipe

Surely one should be doing this anyway, to prevent smells leaking through the pipe?

Pete

 

[nigelmercier]

The replacement pump is a bit more than double the cost of the service kit (at about £57 from what I can see)...

I bought a complete new head for about £20 more than that. Got a spare seat, hinges, new locking pump, and sold the porcelain on eBay.

 

[pappaecho]

The lock and twist function is to prevent siphonage. My recent survey said that the boat must be fitted with an antisiphon valve. I asked the surveyor to look at he push and twist and agreed that it conforms. Pity he cannot read!

 

[Happydaze]

A couple of years ago we fitted a new twist and lock loo as it was only a little more expensive than a replacement pump and seat but the quality of the new loo is very poor up to the original. Now water etc. is coming back down the pipe as before and more paint off the seat in 2 years than the original in 20 years. Maybe Lavac next time.

 

[Hoolie]

See my posts #8 and #10

 

[AntarcticPilot]

Not sure where you are getting your quote from but you can get a complete Twist n Lock pump assembly for under £50 - just do a Google for Jabsco Twist n Lock Pump.

There will come a point at which the service kit just does not do the job. I got to that point a couple of years ago and decided to replace the pump with the Twist n' Lock unit which, at the time, cost more like £70. However, in the end, it worked out almost as cheap to buy a complete new toilet with the Twist n' Lock pump fully installed. Cost was less than £100 (and still is) for the whole thing and as the seat hinges were getting a bit dicy, made sense.

Agree. At all the chandlers where I've seen both on sale, the replacement pump has been less than £10 more than the FULL service kit. However, Jabsco do provide top end and bottom end kits as well as the full service kit; these are, of course, considerably less.

Next time I need a service kit I may well replace the entire pump; the twist and lock style seems to have some minor advantages, and the incremental cost over the full service kit is minimal. I thought I might need one earlier in the year, but on investigation it turned out to be a stainless steel screw that was caught in the bottom flap valve! It must have been dropped in the pan when some work was being carried out.

 

[nigelmercier]

Next time I need a service kit I may well replace the entire pump...

See my post #12