9 Jul 2006
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United Kingdom
I am putting in a small ensuite which will contain a Shower Cubicle, a small basin and an WC. It's at the wrong end of the house and I therefore need to use macerator to pump the waste. As I don't expect it to have a huge amount of use, is it possible to get the less expensive macerator with just two inputs and connect the shower waste to the basin waste before they reach the macerator? Also any recommendations for manufacturer of macerator?

many thanks
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I will only use the Saniflo's & only then if its really has to be done. not sure what the one,s called that accepts a waste outlet but they work o/k you can tee them together but u may get the shower waste backing up when the basin is dishcharged, If you are fitting a basin with a clicker or pop- up waste then the flowrate out of the basin can be slowed down enough to prevent this happening.Once went to one that was only meant for a w/c & they had bossed a basin oto the soil pipe. If they ran hot water into the saniflo it,s thermal cut out switched off the pump untill the hot water cooled down.
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Peter Parry wrote (on the Subject of the Saniflo)

Warning: people of a sensitive disposition might care to venture no further.

Angus asked:

My recently installed Saniflo does not behave as described in the user manual. On flushing the WC it's supposed to run continuously for about 15 seconds, mine pulses on-off 3 or 4 times for about 2-3 seconds duration. Any ideas?

Peter replied:

Sell the house, failing that give it away, if that doesn't work pay someone to take it or burn it down. To give you a clue - these ghastly instruments of the Devil are French. Add the French and lavatorial engineering - now see why I say get out while you can. Moreover this particular Frenchman was a lunatic with strong Anglophobic tendencies and a bad case of coprophilia.

I am quite sure the designer was also an ex-submariner Frenchman who missed the strangled screams of seamen who had got the valve sequence wrong in the submarines toilet and just been rinsed down with a few gallons of seawater (and the recently donated contents of the bowl).

They break down at the slightest opportunity. The only thing you can actually guarantee about them is that they will break down - very frequently. Basically the only way of maintaining the slightest semblance of serviceability is to impose on pain of repair the same rules as for a small yachts sea toilet - if it hasn't passed through you it doesn't go in the bowl.

They have an interesting design. The motor has poor starting torque and the macerator lots of tiny teeth. Ergo anything that has strands in it catches on the teeth and stops the motor from starting. Things with strands include anything with cotton wool (including cotton wool buds) and anything with cloth. Females in particular must not be allowed anywhere near these devices. If you were unfortunate enough to have the added misery of a sink (oh dear - you were warned) then add hair, strands from woolly pullovers and almost anything else that's at all fibrous.

When they break (which they will - that's an absolute certainty) their endearing characteristic is that you are left with a bowl full of whatever which you have to empty back the way it came and more importantly many feet of 40mm pipe still full of minced whatever. When you disconnect the pipe I'll give you one guess where its going to go. Repairing or unblocking them is the most thoroughly revolting job.

Now to get to specifics - the pulsing is a fault in either installation or the pressure switch. Does it pulse with just the cold water tap running from the sink? The way they work is a low pressure trip switch switches on the motor when the small holding tank is full. This tank remains partially full all the time. If its pulsing either the switch has too low a hysteresis or water isn't getting into it fast enough. The motor should remain on for a few seconds after everything has emptied so that pulsing you are seeing shouldn't be happening.

As the failure rate of these diabolical things is worse than that of a F104 Starfighter I'd suggest you get the installer back (preferably to remove it forever). If it was installed by yourself then self flagellation with a few lengths of barbed wire and a call to the Saniflo people might be in order.

Angus asked:

Also, my system is a Sanitop with the outflow from a washbasin going into the top of the unit. I find that running the tap for a few seconds activates the Saniflo. Is there any way of adjusting the sensitivity of it so that it will only run when a reasonable amount of water has gone into the unit?

To which Peter replied:

No, but if it's oversensitive this might be related to the pulsing you are seeing.


I don't see why the washbasin water cant just bypass the cutter/pump internally.


Because these horrors are designed to be installed pumping upwards - the raving idiot who designed them thought it would be pretty neat to have something you could stick in a downstairs cloakroom and run the pipe upwards to join the soil stack in the bathroom. If that's how your installation goes cut out the selling the house bit - just burn it now. When it fails there is 10ft of pressurised whatsit just waiting for that final turn on the drainpipe.

The other reason the sink must go through the pump is that the outlet of the thing is at some pressure. Connect the sink a bit downstream and every time you pull the chain the contents of the loo make a pretty little fountain out of the sink plughole (I've seen one plumbed like that - the owner kept a sandbag in the sink on top of the plug).

Some models have an interesting feature - on the top is a reset switch, under the top cover is a screwdriver slot on the top of the motor drive shaft to allow you to clear the (frequent) blockages. However to get the top cover open to get at the drive shaft to free it - you've guessed - you have to disconnect the drain pipe.

How they can be called Saniflow when they are anything but sanitary (as you will soon find out) and rarely flow is beyond me.

As I said - sell the house.

Peter Parry.

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