Please help Diagnose my latest on board plumbing problem!

[jaminb]

I swear the domestic plumbing on my boat will be the death of me.

Latest problem is that the water pressure pump keeps running. For the last few weeks the taps have been spluttering with air in the system like they do when the tanks have run dry but my tanks are full. Now however the pump will not stop running. Cant find any leaks in the plumbings and have a dry bilge. I did have to replace the cold water feed pipe to the hot water cylinder the other day which involved draining the cylinder but i have refilled and let out the air via the pressure release valve.

I suspect the problem maybe the compression tank ?? (the tank the creates pressure to allow the system to stay pressurised without the pump cutting in) but cant find a concise method to test if this has failed.

thanks

 

[Boathook]

Last time I had a pressure pump that wouldn't stop running, the internal non return valves had failed. The pump also had an internal pressure switch.

 

[wingcommander]

If the expansion tank ( you call compression) failed ,this would not cause pump to continuously run . Its purpose is to prevent nuisance pump cycles switch on thingies. It has a schreader valve to check preasure charge. Even if failed ( diaphragm usually ruptures and it completely fills with water ) it would still allow the pump preasure switch to operate and cut off..
How long does the pump run for when taps closed. If indefinitely then as previously post or your filling the sea up somewhere.

Edit.. may seem strange but check your battery voltage. I had one with duff batteries, would kick in the pump , which then ran continuously, however not powerful enough to build enough preasure to operate the integral switch.
Skipper thought the noise was a passing tender as we sat having dinner.

 

[Clancy Moped]

Do you have a calorifier? if so, check for leaking around that.

 

[Seastoke]

When mine did it it was over temp valve on calorifier

 

[Momac]

I suggest taking the pump off.
Have a look at the inlet filter and clean it.
Open up the pump and clean inside. Check the pressure switch operates by squeezing it. Check the electrical terminals for corrosion, and reassemble.
New O rings on the inlet and outlet .
It worked for me. Not sure what I did that fixed it but there was some limescale and that may have been the issue,

 

[KompetentKrew]

My water pressure pump often keeps running when I refill tanks or switch from one to the other. It used to drive me potty looking for the source of the problem until one day I just turned it off in frustration and ignored it for a while - then when I was ready for another cup of tea, I turned it on again, it ran for 30 seconds and then stopped as it normally should be. So now policy is to turn the pump off and ignore it for some time when it does this, and I find that always works. I mentioned this to a neighbour recently, and he found the same thing.

 

[jaminb]

Thanks for your comments. It is running continually so looks like a consensus towards failing pump. I have now found this historical thread that seems to have very similar symptoms which suggests a diaphgram.

Waterpump; Flojet R4305-505 model - assistance please.

Shame the pump has tripled in price over the last 13 years. If I am correct a service kit is 100 quid!!

 

[Clancy Moped]

If you can get to the diaphgram, slather it in Vasalean, it's not a long term fix very much temporary but it will identify the problem before you put your hand in your pocket.

 

[Momac]

Could be worth trying some other brand of pump

 

[Seastoke]

£100 just buy one

 

[jaminb]

I have now discovered that my model of the Flojet is discontinued so I think I need a service kit!

MartynG that looks good value but doesn't match my existing spec and is ideal for use with an accumulator (expansion vessel) that I have.

Thanks all for input

 

[david_bagshaw]

I swear the domestic plumbing on my boat will be the death of me.

Latest problem is that the water pressure pump keeps running. For the last few weeks the taps have been spluttering with air in the system like they do when the tanks have run dry but my tanks are full. Now however the pump will not stop running. Cant find any leaks in the plumbings and have a dry bilge. I did have to replace the cold water feed pipe to the hot water cylinder the other day which involved draining the cylinder but i have refilled and let out the air via the pressure release valve.

I suspect the problem maybe the compression tank ?? (the tank the creates pressure to allow the system to stay pressurised without the pump cutting in) but cant find a concise method to test if this has failed.

thanks

If the pump works on a flow switch, then it will run id there is air in the system, as there remains a trickle of water passing the switch, keeping it on.
non return valve, failure , often makes the pump cycle, as pressure returns to the tank.