Jan
  • Jan
  • Advanced Member Topic Starter
2012-08-08T15:39:58Z
Hello All

The 2 sinks on Blue Moon are both very slow draining. Both are fitted with "non return" valves to prevent water getting in when the boat is heeled. I suspect these are fitted to most Parkers from the mid 90's onwards. Does anyone know of a suitable cleaning agent for these of it is a mucky strip down job ?

Jan Newman

325/32

Blue Moon

Mike Lockwood
2012-08-17T19:03:40Z
We have a non-return valve only in the heads sink. It drains quite slowly but has speeded up a bit after using a kettle of near-boiling water. I think it's the stiffness of the (?)rubber in the non-return valve rather than detritus that is the problem.

Good luck!

Mike Lockwood

Lucky Devil

Parker 325/35


Mike Lockwood

Lucky Devil

Parker 325/35

geoff.sheddick
2012-08-17T20:43:57Z
Hello Jan,

Without knowing the type of non-return valves, and without seeing a schematic of the installation, I can only offer comment in generic terms:

- the moving or flexible component of all simple non-return valves will be made of a synthetic "rubber-like" material, ideally nitrile, possibly neoprene.

- as such, they will all be subject to age hardening ie they will become stiffer over time, and may take a set in an open position, or and/or no longer open fully. Ultimately they may crack and break.

- however, long before this point, scale and other deposits are likely to have built up on them, which will of itself make them stiffer or even ineffective.

- you can try introducing acetic acid [vinegar] or more expensive proprietary chemicals, but the quickest, simplest, cheapest and most effective solution is simply to take them apart and scrub them clean in hot water!

- then examine them, and if they are now soft and flexible, and without visible cracks or damage, re-assemble them and they will work as originally intended.

- as to how well they work, that is very often a function of the way in which the pipework runs are installed - which in turn is a function of whether the original builder/installer really understood how to install them in order to achieve whatever was his objective...

- your complaint only refers to the sinks not draining properly rather than about seawater flooding in, but if they aren't draining properly, then they almost certainly won't prevent seawater flooding in either!

- if the actual "rubber" valve itself is a more modern cone shape terminating in a Y shaped slit [tricuspoid or "aortic" like a modern toilet and bilge pump valves], then pipework that falls continuously to the skin fitting is fine, but if the valve is a simple flap valve, then it needs to be installed in the Uphill side of an S bend so that gravity holds it shut except when the weight of water leaving the sink pushes it open. Otherwise, gravity will cause the valve to "droop" and age hardening will cause it to "take a set" in this drooped or open position, and when the boat heels, and seawater comes up the pipe, it may well simply flow straight past the open valve, rather than pressing it shut as designed.

- in any event, bear in mind that all these simple so-called non-return valves are very crude affairs - not like a seacock - and can never be relied upon to prevent the ingress of water in the same way as a valve which has a manually operated closing mechanism.

Geoff Sheddick

Parker 27/146 "Stroller'


Geoff Sheddick

Parker 27/146 "Stroller'

Groucho
2024-01-31T17:20:16Z
I was interested to see this post as the survey report on the 275 I have just bought recommended the fitting of a “joker” type non-return valve to the galley sink discharge. I was not sure whether this should be inserted at the sink end or the skin fitting end of the discharge pipe?
Martin Watson
2024-02-12T18:37:02Z
I would suggest close to the skin fitting as the weight of water will be greater to allow it to drain away, or at least to drain below the sink level. Don't forget to double-clip both ends of the NRV. Since I have rearranged the heads layout on my P27 Frith, I now have a sink on the outboard side, discharging through the hull just above the waterline as opposed to through the keel box. I have not had any issues with water ingress as yet but if I do, I will fit a choker-type NRV. I would not fit one to the galley sink as it is closer to the centre line and also I'm not sure food particles would be able to pass freely without partly blocking a choker-type valve. A flap-type valve may be OK as there is a bit of the pipe that runs nearly horizontally in the sail locker.
Martin Watson