Update:
In a flat with a common soil stack. The boiler fitted at high level had its condensate drop into an open 32mm plastic pipe via a flex. The pipe is buried in the wall. An air gap at this point. The non-return valve (costs about £14) is where the drain enters the kitchen, so no waste from flats above can enter the flat - great benefit and the prime reason for fitting the non-return valve. The sink has a dishwasher and washing machine trap. It is connected to the 40mm drain. The 32mm condensate pipe drops into the 40mm drain pipe near the trap. The non-return valve is accessible with the top screwing off (hand tight) to clean the flapper and innards - designed to be user cleanable (McAlpine).
There is always a strong stench coming from the main common stack. There are no smells with the air break in the 32mm condensate pipe ensuring the water from the sink drops down the drain `quickly`. This means solids have less chance of accumulating in the non-return valve. Sorted.
There is no need to have the water trap under the sink as this is just a part that can accumulate solids and need cleaning out by taking the trap apart. However it may be a little difficult to connect onto the part of the trap with the two convenient dishwasher and washing machine connections.
The non-return valve is small, cheap, easy cleanable and beats a HepVO trap all around in `this` situation. The valve has to be horizontal, while HepVO's vertical.
HepVO's have a habit of tearing the membrane (pins, clips) and allowing smells in. If a non-return valve can be fitted I would always go that route.
In a flat with a common soil stack. The boiler fitted at high level had its condensate drop into an open 32mm plastic pipe via a flex. The pipe is buried in the wall. An air gap at this point. The non-return valve (costs about £14) is where the drain enters the kitchen, so no waste from flats above can enter the flat - great benefit and the prime reason for fitting the non-return valve. The sink has a dishwasher and washing machine trap. It is connected to the 40mm drain. The 32mm condensate pipe drops into the 40mm drain pipe near the trap. The non-return valve is accessible with the top screwing off (hand tight) to clean the flapper and innards - designed to be user cleanable (McAlpine).
There is always a strong stench coming from the main common stack. There are no smells with the air break in the 32mm condensate pipe ensuring the water from the sink drops down the drain `quickly`. This means solids have less chance of accumulating in the non-return valve. Sorted.
There is no need to have the water trap under the sink as this is just a part that can accumulate solids and need cleaning out by taking the trap apart. However it may be a little difficult to connect onto the part of the trap with the two convenient dishwasher and washing machine connections.
The non-return valve is small, cheap, easy cleanable and beats a HepVO trap all around in `this` situation. The valve has to be horizontal, while HepVO's vertical.
HepVO's have a habit of tearing the membrane (pins, clips) and allowing smells in. If a non-return valve can be fitted I would always go that route.
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