Airlock? Or domestic water pump on the way out?

[Ric]

Do domestic fresh water pumps fail slowly or catastrophically?

I am a bit baffled with what is going on with my fresh water domestic plumbing system. Over the winter, I modified my transom shower to have a hot water mixing tap - this involved installing a T-junction at the hot water outlet from the calorifier, and an approx 2m hot water pipe to a mixer tap at the transom.

Unfortunately this seems to have had a rather profound effect on the functioning of the entire domestic water system. Whereas previously the water pump took just a couple of seconds to pressurise the circuit before it cut out, it now takes 20-30 seconds. Moreover, the flow from all outlets in the circuit (heads, galley and stern shower) is now about half of what it was. I suspect an airlock in the system - if so how to get it out?

Or could it be that my water pump is on the way out?

 

[Bav34]

My pump recently had a small leak ... easily repaired. However I then had your symptoms:

Whereas previously the water pump took just a couple of seconds to pressurise the circuit before it cut out, it now takes 20-30 seconds. Moreover, the flow from all outlets in the circuit (heads, galley and stern shower) is now about half of what it was. I suspect an airlock in the system - if so how to get it out?

It was obvious that the accumulator tank was empty.

I kept powering up the water then turned the power off, then opened the taps. After a few cycles the tank filled and I am now back to normal.

Failing that go back to the original set up ... take out the t-piece and reconnect the pipes using a straight-through fitting ... if you still have the problem I guess it's not your mod causing the problem.

 

[Caer Urfa]

Do domestic fresh water pumps fail slowly or catastrophically?

Or could it be that my water pump is on the way out?

Hi Ric

Not sure what make and size of pump you have and the distance you want to pump.

Most of the well known fresh water pumps are self priming, from your description it sounds to me due to your additional modifications the pump is now not big enough for the job.

One way just to prove it is by pass some of the new work to see if the pump still works.

Mike

 

[VicS]

A good run with all the taps open should get rid of any air but I dont think your symptoms are those of air in the system.

Do you have a filter in the pump suction .. you probably should have. If so check it and clean it if necessary. (If you dont then perhaps you should fit one.)

You pump may have some dirt in its valves somewhere. Or a defective or worn valve. Simple to strip clean and replace defective parts if that is the case.

You dont say what pump!

If a Jabsco you will find exploded diagrams and parts lists including overhaul kits on the Jabscoshop website

 

[charles_reed]

If you have an accumulator in the system the highest probability is that it needs pumping up, or the bladder has gone and it needs replacing.

If you have a direct action system (becoming more common than previously) your pump capacity is too small.

There are other more arcane causes - as I found out in Kalamata - but let's not go into the possible electrical causes.

 

[dje67]

The pump suction-side being blocked gets my vote. Mine blocked with a piece of silicone sealer (from the tank access hatch) at the inlet to the pump. This meant that the overall flow was low and it took ages to pressurise the accumulator. Once I eventually found the problem, the system has worked perfectly since. I cleared it by reverse-pumping water & air back from the pump to the tank and out popped the blockage.

 

[daveyw]

As VicS said. 99% sure its the blocked inlet filter or if no filter, a bit of dirt in the pump valves