575/588 - Grey Water Pump Problems

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Grey Water Pump Problems

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 575/588
Forum Description: 575/588 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=10392
Printed Date: 26 March 2026 at 23:38
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com

Topic: Grey Water Pump Problems

Posted By: Mtf
Subject: Grey Water Pump Problems
Date Posted: 28 July 2017 at 23:16

After 18 months the pump for the grey water tank that takes water from the kitchen sink appears to be becoming rather unreliable, at times it seems to pumps for long periods without seeming to move any water. I blame this on the fact that various bits of food waste have got into the tank over time and it has become rather mucky down there. For the past few months we have moved to pouring the washing up bowl out into a sieve in an attempt to make sure the water is rather cleaner, but it might be a case of too little too late.

This evening it was labouring continually and moving no water at all. I took the cover off the grey water tank and removed the water by hand. After a little thought I decided to run our fresh water hose pipe down to the grey water tank and push the hose through the hole in the grey water tank that leads to the pump. It was a nice snug and largely water tight fit. I switched the fresh water on to create some pressure and set the pump running by putting the sensor into some water. The pressure from the hose resulted in the pump working just fine and the blockage appeared to clear. I left it running for 30 seconds or so and then stopped the pump and hose. When I put everything back together the pump worked perfectly.

I don't know if I have just re-invented the wheel or whether this is a bad idea for some reason, but I thought it might be information worth sharing.

Replies:

Posted By: marcopone
Date Posted: 05 August 2017 at 00:10

I also had a lot of issues with this grey water system/pump, I report my experience:

The problem you are reporting, pump on for long time but no pumping, in my case was due to some air trapped in the pump (air lock).
After many tests and pump dismantling for cleaning, I discovered that just loosening a little the clamp on pump outlet hose to let some air out was resolving the problem.
In the end I changed the pump mounting position and had a more logical inlet and outlet hoses layout and this did not happen again.

As second modification I changed the tank level:
I noted that the tank was inclined down to the center of the boat and the tank's outlet to the pump was on the bow side. Because of this heavy parts and much dirt deposits were remaining in the tank.
I put about 6 cm high wood board under the tank to change the inclination toward outlet to pump suction and it works much better, longer fixing screws are needed.

At last I often have problems with the electronic conductive level switch.
I already changed about 4 level switches in 4 years - for the 2 tanks.
Following my supplier recommendation I installed a relay.
This because it seemed that the pump amp load was too much for the level switch.
The situation improved but I still need to clean the lev switches frequently.
What worries me is that, if I do not notice soon that the pump does not stop, it will stay on for a long time.
This is not good for the pump as the motor will overheat and eventually fail.

I am now doing some tests with this level:
I changed the level position within the tank and raised it some cms, shortening the plastic bars.
Then I cut off some plastic parts of the level, top and bottom, to reduce the dirt cumulating on the sensor.
If it works better I will post some pictures.
My hope is to increase the cleaning time interval.