I have a amara 380/2. I find that when I remove waste plugs to the sink and hand basin it takes ages for the water to drain. I have flushed out the pipes and even removed the bung to the waste tank to remove any air locks to no avail. Is this normal or is there something I have over looked.
We find that to help the sinks drain better the caravan should be very very slightly off level tipped ever so slightly in the direction of the outlet which for us means having the nose up a teeny little bit so there is a better run to the outlet.
The wash basin and kitchen sink at home have an overflow at the top near the water taps whereby air can flow above the draining water allowing the water to drain much faster. In caravans there isn't an overflow on either the wash basin or kitchen sink therefore waste water takes longer to drain slower. However, due to the smaller diameter waste pipes in a caravan, they can get clogged up quicker which is evident when the water takes ages to drain or stops draining at all. The solution is to put the drain plug in the sink then fill about half way with cold water. Pull the plug out and immediately use a rubber plunger to dislodge any debris which works for me every time as the water drains much quicker. When that is done I pour down some drain unblocker and leave for about 30 minutes then flush through the plug hole with hot water (not boiling). Finally, have a look in the waste water tank and the evidence should be by the colour of the water which if any gunge has been flushed out it should like a dirty caramel colour.
Regarding the overflow, the principle is the same as filling a bottle with water then tipping it up to drain. If you allow air in over the surface of the water then the water will freely flow. If you tip the bottle into a vertical position then water escapes in gushes due to a lack of air flow.
Quite a few reasons why caravan sinks drain slowly, Tango 55 covered some, but the plumbing itself is less than ideal! The waste pipework is relatively small bore, it's at least in part usually corrugated which is not conducive to good/quick water flow, and unlike domestic plumbing it is usually affixed under the floor without any 'fall' to encourage flow (that's why having a bit of a slope on the van in direction of waste exit point can improve flow).
The flow is reliant upon a combination of 'head' (the height of water above lowest EXIT point, not necessary the lowest point in plumbing) which under gravity forces water down the pipe, and the suction effect of a mass of water moving at some speed down the pipe, unfortunately that is minimal with the slow drainage in a caravan. That slow flow and the corrugated piping encourages constrictions and blockages to build up. To some extent it's just a inherent 'feature' of caravans, but can be minimised by ensuring pipes are clean and blockage free.
Why oh why don't caravan manufactures use 32mm domestic waste pipe and fittings instead of the thin corrugated pipe. The corrugations tend to hold waste and eventually block or restrict the flow. I know it's easier and cheaper to use crappy pipes but for God's sake the price of new vans need decent materials used. I replaced all the old waste pipes on my last van with 32mm domestic waste pipe. It worked perfectly and still is. OK I had to make afew 25mm to 32mm fittings but no real hardship. I'm going do the same to my new to me caravan in the next few months.
Quote: Originally posted by SHANTY SINGER on 15/7/2023
Why oh why don't caravan manufactures use 32mm domestic waste pipe and fittings instead of the thin corrugated pipe. The corrugations tend to hold waste and eventually block or restrict the flow. I know it's easier and cheaper to use crappy pipes but for God's sake the price of new vans need decent materials used. I replaced all the old waste pipes on my last van with 32mm domestic waste pipe. It worked perfectly and still is. OK I had to make afew 25mm to 32mm fittings but no real hardship. I'm going do the same to my new to me caravan in the next few months.
"I know it's easier and cheaper to use crappy pipes" - which seems to be the answer.
I would add another question.
"Why do they use 'slop-fit' connections in the waste-pipe runs and leave them unsupported, so that when the van gets jolted on rough roads the waste pipe will spring a leak?
(Usually in some place where you cannot reach to effect repairs without dismantling half of the van.)
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Topic: Fittings drainage
via mobile 14/7/2023 at 6:30am
