Air leaks in water system?

[renegade27]

My water pressure pump comes on every 3-4-5 minutes for just a second or two. Very annoying - - and probably indicative of something wrong.

I'm thinking there an air leak in the system -- but oh no, that sounds like a PIA. If so, how does one chase airleaks in the system?

Other ideas?

Thanks!

[rene460]

Hi Renegade27,

Water pump running for a few seconds periodically, often when all is quiet, is more likely to be a water leak out of the system which eventually lowers the pressure in the system enough to hit the low pressure start setting and start the pump to recharge the accumulator.

Air pressure is less than the water pressure everywhere but at the pump inlet, but as pump is not a very good compressor, it tends to run continually rather than for a few seconds if air is leaking into the pump inlet.  Higher pressure water leaks out,  air does not leak in.

i suggest a careful search for a few drips of clean fresh water.  A suggestion is either end of the transom shower hose as the shower head is often unconsciously given half a turn each time it is put back in place.  This can loosen the screwed connection, relatively easily fixed.  If the pump runs every 5 min or so, I suggest you will find quite a pool when you start looking.  A drippy tap would also do it.

Otherwise any other joint in the system.  Newspaper laid at selected places can sometimes make a few drops of water easier to spot.   The good news is that it does not continue once you switch off the pump on leaving the boat.

Another possibility is leaky pump valves, as the pressure in the accumulator can force water back through the pump, but as both inlet and discharge valve must leak, I think it is less likely unless the pump is extremely old, or perhaps water quite dirty.  Cleaning the valve seats or a new pump valve kit will cure this one.

rene460

[sailbleu]

This is a process of elimination.
Switch on the pump and when the desired pressure is achieved it will stop. Then close the suction valve.
When the pump doesn't come on after 5 minutes it needs an overall.
In the other case prepare for a quest.

Good luck

Regards

[alcheringa]

We had this problem which turned out to be a very slow leak from the water heating tank. After chasing our tails for quite a while we narrowed it down to a weeping soldered joint in the copper tank. Took about 45 minutes to pull the tank out, fifty Euros to get it re soldered and pressure tested,(In Sardinia) and half hour to get it all back. No problem ever since. Good luck finding your problem.

Cheers

SV Alcheringa
www.dreantimesail.blogspot.com

[renegade27]

Think I found it. Hot water tank lever open and draining into the bilge. Emptied the water tank during the work-week.

There was a screw cap over one of the junctions going into the tank which, with about 15 degrees of turn seemed to stop the flow into the bilge.

The boat manual on the hot water tank is weak - i admit this engineer really doesn't know how to open/ close/ drain/ seal, et.

The make on the tank is obscured as well as there is foam insulation covering everything.

Anyone find a good resource on how this system works?

[rene460]

Hi Renegade27,

It is possibly the pressure relief valve on the hot water tank.  I am too far from the boat and my documents at the moment, but I suggest that you might find this forum your best resource if you rummage back through old posts using the search function.  I recall some threads on this issue a couple of years back.  Others may also reply with more recent knowledge.

I would have thought that the accumulator should have accommodated the water expansion without lifting the pressure relief valve, so it might be worth thinking about whether it still has sufficient precharge of air.  There was something about calcium accumulating under the pressure relief valve seat on hot water tanks due to the valve weeping slightly, causing mal operation of the pressure relief valve.  It may need disassembly and cleaning or replacement.  Turning the screw under the cap may have just altered the pressure setting and may be only a temporary fix with un intended side effects.  Leaving the water pressure system off when you leave the boat should prevent recurrence when you are away, especially if you briefly open a tap after switching off to de pressure the system.

I am sympathetic to your feeling of being unable to do some simple tasks, as when you normally deal with more complex equipment, you usually have more complete documentation and other assistance.

rene460