Clearing soap build-up from drainpipes

[RichD1]

Hi Guys,

Spent the morning under the utility sink in muck & bullets removing all the 'gettable' drainage pipes right up to the sink and removed loads of soap build-up.

My question is; how do I clean up the pipes which I can't get at?

I can see the outlet over the outside drain. Should I try and bung this up and then pour a solution of something down the drain until it backs up to the sink and allow to stand for a while?

But what cleaner is going to be effective?

I do have some strong degreaser that I use in the workshop, will they be any good?

Richard

 

[Jackrae]

boiling water ?

Failing that caustic soda crystals (not washing soda) and cold water (the exothermic reaction will heat it up)

 

[RichD1]

The utility sink is one of the hottest taps as it is right next to the boiler and gets frequently used with hot (65C) washing up. I always run some hot water down once any washing up is done, but it still seems to build up.

Think I will try the bung and caustic soda for say 15 minutes and then flush down with boiling water.

Richard

 

[Jackrae]

So what are you putting down the drain that causes it to block up - or is the pipework trying to flow water uphill in an area so creating a low spot where debris/gunk can accumulate

 

[JohnD]

you say you wash up at the sink. Could it be cooking fat?

If it really is soap, it will dissolve if you spoon it into boiling water. If fat, it will melt and float on the top.

 

[RichD1]

I hadn't blocked up but I noticed that it had been draining slower recently. It's mainly washing up but it does get some fat down it but this is usually diluted with a few squirts of washing up liquid in hot water before emptying down the drain.

What came out was a black sludgy mesh which easily broke up when I rinsed it in the kitchen sink. I think it was mostly soap as I wasn't left with any oily deposits on my fingers.

In the configuration that I've got under the sink there is a short run which has just a small fall from the P trap but that feeds into a vertical drop which then meets the bottom run at a T piece from the dishwasher and then goes out through the wall behind the units.

The main build up was in the sink strainer fitting and some in the P trap with only a small build up in the small horizontal run, but there was more build up in the vertical drop. Where it entered a T piece at the bottom I could feel sludge inside this fitting too.

Richard