Water Pump

[StoneHenge]

Our water pump recently has been coming on, then running slower to stop (as normal) but then staying at that low rumble for ages before cutting off. It didn't do it before, and seems to improve with higher coltage (like when the generator is running), but seems to struggle a lot.

 

Is this a sign that it is on its way out?

 

How much is a decent water pump these days?

[RobinJ]

Our water pump recently has been coming on, then running slower to stop (as normal) but then staying at that low rumble for ages before cutting off. It didn't do it before, and seems to improve with higher coltage (like when the generator is running), but seems to struggle a lot.

...

How much is a decent water pump these days?

Sounds like its still working!

No sign of leaks, dripping taps etc.?

Whats the voltage like - take it gnerator is supplying 12V?

Are there any dodgy connections, rusty chocolate blocks etc.?

Possibly the pump has furred up a bit, does it have an inline filter that needs cleaning?

Has the outlet pipe from the tank (often steel) rusted up reducing the flow?

 

It could be just that there is not enough current to run the pump up to full pressure quickly!

Need to check battery voltage - pump voltage, how much difference?

 

A decent sized pump is now around £90-£100.

[John Orentas]

Our water pump recently has been coming on, then running slower to stop (as normal) but then staying at that low rumble for ages before cutting off. It didn't do it before, and seems to improve with higher coltage (like when the generator is running), but seems to struggle a lot.

 

Is this a sign that it is on its way out?

 

How much is a decent water pump these days?

 

 

The pressure switch may be set for a to high a pressure making the motor labour under the increased load, or your wiring may be be a bit 'light' for the job, might even be a bad electrical connection somewhere.. is there any way you can measure the voltage at the pump..

[StoneHenge]

As far as we know, there are no leaks we can trace. The only thing we have found is that the water pumo every so often goes off and this seems to be in conjunction with the back loo that flushes itself sometimes probably due to the back loo being on the slope and it detects less water pressure in it as it is always lower than the front loo.

 

We did have a pressure relief valve issue but that was fixed some time ago now with no other problems.

 

We do have voltometer we can check the volts with. What sort of output should I be looking for?

 

Thanks for the advice chaps.

[RobinJ]

As far as we know, there are no leaks we can trace. The only thing we have found is that the water pumo every so often goes off and this seems to be in conjunction with the back loo that flushes itself sometimes probably due to the back loo being on the slope and it detects less water pressure in it as it is always lower than the front loo.

 

We did have a pressure relief valve issue but that was fixed some time ago now with no other problems.

 

We do have voltometer we can check the volts with. What sort of output should I be looking for?

 

Thanks for the advice chaps.

The voltage to the pump should not be more than about 0.5V lower than the battery, but important to note if it drops when it is running!

Its possible there is a problem with the pressure cut off, if water is getting past the valve in the back loo, it may be that this is relieving the pressure as it builds up to high?

Do I take it (PRV) also a calorifier too?

You might need to find out whether the pressure switch is build into the pump or mounted separately?

[StoneHenge]

The voltage to the pump should not be more than about 0.5V lower than the battery, but important to note if it drops when it is running!

Its possible there is a problem with the pressure cut off, if water is getting past the valve in the back loo, it may be that this is relieving the pressure as it builds up to high?

Do I take it (PRV) also a calorifier too?

You might need to find out whether the pressure switch is build into the pump or mounted separately?

 

That sounds like sound advice, but as a Sheila I am about as electrical as a dead sheep. I'll point the man in the right direction and see if he can find out nall these juicy details.

 

Despite them not sounding silly expensive, it does sound from the replies that it is probably something other than the pump itself.

 

I'll get the gadget on it and see what we come up with.

[StoneHenge]

The water pump isa jabsco carmax 4 20 psi. We took a look at the pressure relief valve (on hot water tan) and it is leaking out of the back when the pump is stopping. Hubs said he wondered why the engine room was wet (even despite the rain~). This suggests the pressure is too high?

 

Is there anythng we can do? Sorry, not great with stuff like this!!

Edited September 5, 2008 by StoneHenge

[John Orentas]

Forget my post, didn't see the Jabsco bit !

Edited September 5, 2008 by John Orentas

[alan_fincher]

The water pump isa jabsco carmax 4 20 psi. We took a look at the pressure relief valve (on hot water tan) and it is leaking out of the back when the pump is stopping. Hubs said he wondered why the engine room was wet (even despite the rain~). This suggests the pressure is too high?

If you PRV on the calorifier is leaking when the water system gets up to full pressure, I'm not convinced it's necessarily a pump fault.

 

Surely it's just as likely a PRV fault?

 

Does the water pressure at your taps seem excessive, or higher than you are used to ? If it doesn't I'd investigate the PRV first.

 

Alan

[StoneHenge]

thats the thing Alan, we have had the prv replaced twice and the engineer chappy said if the valve keeps going, it could be the pump.

 

As you say the tap pressure is fine, no air in the system the filter is clean, pressure seems to be OK too.

[bottle]

I am clutching at straws here, how can a 20 psi pump 'lift' the PRV, I am guessing the PRV is greater than 20 psi about 1.3 bar.

 

Note: no qualifications and probably talking out of my posterior.

[alan_fincher]

I am clutching at straws here, how can a 20 psi pump 'lift' the PRV, I am guessing the PRV is greater than 20 psi about 1.3 bar.

 

Note: no qualifications and probably talking out of my posterior.

Also talking out of my posterior, not having a calorifier (yet)....

 

But my thinking is...

 

1) If PRV is correct, then the water pump shouldn't be generating enough pressure to overcome it.

 

2) So if water is coming out of PRV, when pump operates, either pump is generating too much pressure, or PRV is letting water past when it should not.

 

That's why I asked about pressure at the taps.

 

If that's gone ballistic, then, fine, suspect the pump's pressure cut out switch.

 

But if normal cold water pressure from taps is as expected, I'd be doubting the PRV. (They do often seem to let water by when they shouldn't, from posts I've seen).

 

If that's crap, somebody please say!

[rover220]

replace the pressure relief valve and ill bet the pump works as it did. if the relief vavle is leaking, the pump will have to work for longer to reach set pressure.

 

ive not seen a parmax pump fail and have fitted so many of the things.

[smileypete]

The water pump isa jabsco carmax 4 20 psi. We took a look at the pressure relief valve (on hot water tan) and it is leaking out of the back when the pump is stopping. Hubs said he wondered why the engine room was wet (even despite the rain~). This suggests the pressure is too high?

 

Is there anythng we can do? Sorry, not great with stuff like this!!

 

Try twisting the knob on the PRV anticlockwise, there may be a little scale under the valve seal that's making it leak.

 

cheers,

Pete.

[blackrose]

If it turns out to be a pump issue try calling Mack Engineering (suppliers of Jabsco pumps) for advice. 0141 882 1030

They're very good on the phone (at least they gave me some good advice and were very patient)

[charles123]

I would bet on the PRV, replace it for about £10

 

The tell tale sign if its leaking is to look outside of the boat at the overflow outlet, if there are signs of dribling then its the PRV

 

Charles