Blocked Kitchen Sink

The_Mad_Rapper

Firstly, I hope this is in the right place. Apologies if not.

I am seeking advice with a blocked kitchen sink. I have tried a number of things, but none have been successful so I thought I'd ask advice before calling in the professionals.

The background to the issue is as follows:

On Sunday evening, while running the tap in the kitchen, it started to fill and was obviously blocked. We own a 3 floor Town House and the kitchen is on the first floor. The sink is of the double type - the left side being a normal sink, the right side having a garbage disposal unit fitted. Both sinks have separate pipes connected to the same downpipe which then disappears under the floor. The left sink fills, then the water level within the garbage disposal rises shortly after. If the garbage disposal is spun up while the left sink has water in it, the disposed water and waste appears out of the left sink.

I have tried the following:

Poured at least 20 litres of boiling water into the sink - No effect.
Plunged - No effect.
Removed all pipework from both sinks and confirmed no trap blockage - No effect.
Poured a litre of One Shot directly into the down pipe with the sink piping removed - No effect.
Poured a caustic soda solution directly into the down pipe with the sink piping removed - No effect.
Bought a 25 ft drain snake and extended it to maximum length. Repeated 5 times - No effect.

Assisting Information:

Every other sink, bath and shower drains without issue.
The drain snake came out of the sink in the bathroom next to the kitchen. When reversing the operation, and putting the drain snake down the down pipe in the bathroom sink, the drain snake came out of the kitchen sink downpipe. So, the two sinks are clearly connected, the pipework between them has been cleared at least 5 times, but the kitchen sink remains blocked while the bathroom sinks continues to drain perfectly.
After reassembling the kitchen pipework and running the hot tap, or pouring down boiling water, the sink fills again quickly, but while filling I can hear air gurgling from the garbage disposal. The water level holds steady for a while, then very slowly recedes. After the water has fallen below tap level, to what one would assume is the normal level within the trap, there is significant 'gurgling'.

I am not brilliant at DIY, but I've tried everything I can think of. The only other thought is that perhaps the kitchen sink has a vacuum issue? I have read of 'vents' on the internet, but I would have no idea how to confirm this. Further, as both kitchen and bathroom sinks are connected, one would assume they would share the same vent. But as the bathroom sink drains perfectly, this can't be the case.

I am utterly baffled. Can anyone help?

cyclonebri1

Can't believe the fact that you have done everything possible that I would have done:T (that's praising you, I have a little experience)

The 1 thing that to haven't done is to reconnect, block any other exit routes, and apply pressure to the system.
Easier than it seems with a simple plunger, the big rubber thing you see plumbers carrying about.

The acid treatment that I think you have used is today's favoured method, it does need time without dilution, any water that can be removed 1st will increase it's efficiency, you may need to try it again.

But back to applying pressure, a method that hasn't failed me yet is to use an air compressor to the blocked line, hose down pipe and rag around it, will clear or blow at the blockage

The_Mad_Rapper

I have plunged, and we tried blocking the garbage disposal and the little vent in the main sink, but it wasn't successful.

Ideally, I'd buy a cap for the garbage disposal pipe, disconnect the trap and screw that on, leaving only the sink drain and the sink vent and plunge that. I suppose it's worth a try.

Is there anyway to completely block the little vent in the sink? A wet cloth doesn't stop the water coming out when I plunge down.

The_Mad_Rapper

Can you give me an example of the air compressor you mentioned please?

Is it a pump? Or compressed air?

Thanks so much.

cyclonebri1

The_Mad_Rapper wrote: »

I have plunged, and we tried blocking the garbage disposal and the little vent in the main sink, but it wasn't successful.

Ideally, I'd buy a cap for the garbage disposal pipe, disconnect the trap and screw that on, leaving only the sink drain and the sink vent and plunge that. I suppose it's worth a try.

Is there anyway to completely block the little vent in the sink? A wet cloth doesn't stop the water coming out when I plunge down.

You need another pair of hands, or my earlier suggestion, (that allows for a certain amount of leakage).

cyclonebri1

cyclonebri1 wrote: »

You need another pair of hands, or my earlier suggestion, (that allows for a certain amount of leakage).

I'm a practical bloke, I just have a compressor to power tools, sprayers etc, if you don't have then it would be more expensive than a pro drain buster service, sorry

The_Mad_Rapper

cyclonebri1 wrote: »

I'm a practical bloke, I just have a compressor to power tools, sprayers etc, if you don't have then it would be more expensive than a pro drain buster service, sorry

No worries, I understand what you meant now. I think I'll buy the cap for the garbage disposal drain feed and a better plunger and give plunging another go.

Thanks for your help.

MadelinesMum

When ours was blocked I covered overflow and used our vax carpet washer to suck it up. If the sink is double / has a half sink as well, you have to cover that plug hole and overflow too, or the suction just comes out there. Turned out Dd had cleaned her guinea pig out in the sink and washed bedding down there!