macerator causing problem

[connaught]

Hi hope someone can help,
Recently fitted a new macerator as last one died after tap being left on all weekend, same model saniflo. just noticed that when flushing it creates sufficient pressure to cause water to flood out of top of washing machine discharge pipe via the trap as though it back flushes my wates under the sink. it never used to do this. any ideas to solve this?
cheers

 

[Puddle]

Well if the washing machine outlet also goes into the macerator also then the non return valve/arm inside unit is stuck open maybe by waste pipework pushed to far into unit or maybe not fitted correctly thus inlet staying open when pump activated and it will pump out unit outlet and up washing machine inlet pipework also

 

[Mike Jackson]

How is the macerator connected? It should connect straight into the soil stack.

Mike

 

[Puddle]

How is the macerator connected? It should connect straight into the soil stack.

Mike

Hi Mike

Was going to go down that route but as same unit fitted as a replacement and all ok before persumed that sink was not plumbed into macerator outlet but all is possible,obviously if this is the case the waste from the sink should be correctly run asap as not only back filling problem but also major health risk

 

[connaught]

Hi, no the macerator and washing machine are both seperately plumbed into soil pipe but are on opposite sides of the pipe, im thinking there perhaps is enough pressure to pump straight across soil pipe and up outlet of washing machine,

 

[Mike Jackson]

That sounds like your problem. You've 2 options, move one of the connections or replace the trap on the WM pipe with a HepVo valve and running adaptor.

Mike

 

[connaught]

so the hepvo is is basically a non return valve used in this application?

 

[NickH]

Basically, yes.

 

[Puddle]

If there is enough pressure now, to back up the waste pipework opposite then when Hepvo valve fitted in this instance, same thing could happen if the macerator discharges the same time as the washing machine or sink, as pressure from waste water from macerator could in effect cause a temporary restriction /blockage in sink waste pipework, even closing Hepvo valve, thus water from sink/washing machine will then back up and spill out as is now happening,only instead of macerator waste you get sink/washing machine waste water
Best bet long term and good practice to stagger pipework entering soil pipe