Water Pump Issues.

[Horace42]

I can't see any reference in any replies whether you problem has grown on you. Has the pump run normal in the past and only just started running at night? This points to having an accumulator in the system that has gradually lost it's air.

 

Pumping it up with air will cure the problem. You don't need to worry about the exact pressure, just a few strokes of the pump to start with will stop the pulsations (rapid on/off) - that still happen but at longer intervals between on/off (with a tap running slowly). The accumulator pressure matters (if know what it should be) if you want maximum effect - and if Dad has a pump with a pressure gauge - and matching pump connector.

[Geo]

Ow darn ive started something now. Lol

 

Am going to bed now an update tomorow.

 

(Hides behind my leather recliner)

 

You go and sleep, you were going to bed ages ago. Did you have that Vodka

 

Sleep well

[Greylady2]

You go and sleep, you were going to bed ages ago. Did you have that Vodka

 

Sleep well

No Vodka just some Sharaz and a bloody lively dog telling me it not bedtime. lol

 

Am in bed now so you sleep well too.

 

:-)

[Horace42]

My homemade expansion vessel, a champagne bottle enclosing a blown up balloon likes to be mounted upside down as if mounted in a pubs optic.

Great idea. What! still with champagne in it connected to a tap at the sink?

[Chewbacka]

 

If my lousy logic is correct. If the expansion vessel is fully charged; as the water cools, the water pushed into the expansion vessel as the water was heated, will return to the calorifier. Thus there should be no change in pressure on the cold water side let alone a drop in pressure on the cold water side that would trigger the pump. If the expansion vessel is empty of air there is no pressure in it to return the water as it cools to the calorifier and thus the water pressure in the calorfier drops to below that of the cold water supply and sucks water into the calorifier causing a drop in the pressure in the cold water side thus triggering the pump.

 

So my logic, lousy logic, says the probability is the expansion vessel has failed. That can be either be because the pressurising air has leaked out of the bladder or the bladder that holds the air has failed releasing the air into the water. If pumping air into the expansion vessel via the valve on the top pressurises it then all is OK and the air is replaced and the pump should not run as the water cools. If it does not pressurise, the the air is just being pumped into the water and a new expansion vessel will be needed.

The expansion vessel is there to cope with expansion and not as an accumulator so is pressurised to a pressure just above the pump cut off pressure. When the pump turns off little water will have entered the expansion vessel. As the water heats it expands and to stop the pressure rising too high it flows into the expansion vessel. If the heating is off/engine stopped and some hot water taken from a tap the pressure will fall the pump will run and cut off at normal pressure, which being below the expansion vessel pressure will not push water in. As the water cools it will contract and quite quickly and as there is no accumulator on the pump the pressure will drop enough to trigger the pump.

[Geo]

No Vodka just some Sharaz and a bloody lively dog telling me it not bedtime. lol

 

Am in bed now so you sleep well too.

 

:-)

 

I shall just going to bank up the morso get a hot drink and climb the stairs and slide into a chilly bed that will warm in seconds and sleep like a log.

 

BTW for dad tomorrow.

 

Turn off the water pump, turn on both of the taps, connect the pump to the valve on the top of the expansion vessel and pump up to the pressure marked on the side of it to start with.

[Geo]

The expansion vessel is there to cope with expansion and not as an accumulator so is pressurised to a pressure just above the pump cut off pressure. When the pump turns off little water will have entered the expansion vessel. As the water heats it expands and to stop the pressure rising too high it flows into the expansion vessel. If the heating is off/engine stopped and some hot water taken from a tap the pressure will fall the pump will run and cut off at normal pressure, which being below the expansion vessel pressure will not push water in. As the water cools it will contract and quite quickly and as there is no accumulator on the pump the pressure will drop enough to trigger the pump.

 

Working on the premise that it did not do it before I will stick with my logic. If it had always done it from new I would agree with you. It all depends on the pressure that was set in the expansion vessel originally or whether it was left at 31lb psi as it was delivered. Don't know

[Chewbacka]

 

Working on the premise that it did not do it before I will stick with my logic. If it had always done it from new I would agree with you. It all depends on the pressure that was set in the expansion vessel originally or whether it was left at 31lb psi as it was delivered. Don't know

It's a good question raised, being why didn't it do it before?

 

Thinking about the possible system changes, I can only really think of a small leak or weeping pressure relief valve, but then I thought what about external changes?

 

So for example - the weather has got colder and the daylight shorter so the engine/heating could be on for a lot longer resulting in much hotter water.

For example if the engine is used to heat the water the thermostat is often quite low - say 75c - but if using shore power to an immersion heater or a boiler the thermostat could be more like 80c or even 90c

Being on of longer (including engine running) would heat the entire tank rather than just the top half of the tank

The water being a lot hotter may not be noticed as there is probably a thermostatic mixer on the output of the hot tank.

 

Now couple this with the boat being colder when asleep at night then there is going to be a lot more cooling of the hot tank and consequent contraction of the water as it cools. Without an accumulator this will result in more pump running to 'top up' the pressure.

 

This is all speculation, but it could explain why this is happening more now than in the summer and why there may no no problem to find.

 

Anyway let's wait for the results of today's work.

[Geo]

It's a good question raised, being why didn't it do it before?

 

Thinking about the possible system changes, I can only really think of a small leak or weeping pressure relief valve, but then I thought what about external changes?

 

So for example - the weather has got colder and the daylight shorter so the engine/heating could be on for a lot longer resulting in much hotter water.

For example if the engine is used to heat the water the thermostat is often quite low - say 75c - but if using shore power to an immersion heater or a boiler the thermostat could be more like 80c or even 90c

Being on of longer (including engine running) would heat the entire tank rather than just the top half of the tank

The water being a lot hotter may not be noticed as there is probably a thermostatic mixer on the output of the hot tank.

 

Now couple this with the boat being colder when asleep at night then there is going to be a lot more cooling of the hot tank and consequent contraction of the water as it cools. Without an accumulator this will result in more pump running to 'top up' the pressure.

 

This is all speculation, but it could explain why this is happening more now than in the summer and why there may no no problem to find.

 

Anyway let's wait for the results of today's work.

 

 

As you quite rightly say it is all speculation, which all paper based fault finding always is. We sit at a keyboard sifting information and trying to get it to talk to us and give us that one nugget that will help us lead the poster to the fault and a solution. Some are easy some like this one because of possible interactions between different parts of systems with each other can be a headache.

 

Leaks have been looked for and all is reported as dry and no leaks. The only daytime problem reported is tap pulsation. Now if this did not happen previously it could be linked to whatever the cause is, the belief is that it is a post fault happening. Thus somewhere there would seem to be a pressure balancing effect that has ceased working or reduced its effect. Like most people my first thought was an accumulator problem but there is not one or one has not been found. There is however an expansion vessel which has a similar ability to an accumulator, so logic says check its pressure.

 

So it is wait for lovely dad to do the check and see where it all goes.

Edited November 25, 2016 by Geo

[WotEver]

Shall I join in?

 

This is all speculation so let's wait for Dad to check it out and see what progresses from there.

[Greylady2]

Hi again i checked the pressure on my expansion vessel and it read 27-28psi so i pumped it up to 38-39psi as advised.

 

Their seems to be more water pressure now and the water pulsating while tap is only just on is still their but no where near as much.

 

All i can do now is hope the water pump does not kick in at night time.

 

Here are the readings ;

 

A massive thanks for all the help you lot.

 

:-) :-)

Edited November 25, 2016 by Greylady2

[WotEver]

Let's see tomorrow if you have a pump-free night tonight

[Greylady2]

Let's see tomorrow if you have a pump-free night tonight

Yep i will have to learn how to post smiley faces. Lol

[Geo]

Hi again i checked the pressure on my expansion vessel and it read 27-28psi so i pumped it up to 38-39psi as advised.

 

Their seems to be more water pressure now and the water pulsating while tap is only just on is still their but no where near as much.

 

All i can do now is hope the water pump does not kick in at night time.

 

Here are the readings ;

 

A massive thanks for all the help you lot.

 

:-) :-)

 

That looks good. Now we need a cool night and see what that pump does.

 

Greylady how difficult is it to see which model the water pump is. Think you will need to lift the board above it if that is possible.

[bizzard]

Yep i will have to learn how to post smiley faces. Lol

Why not just switch the pump off overnight, all those little burps are using the battery.

Fresh water pumps last much longer if switch off when they're not going to be used for some time, and some water run off at a tap to relieve it of the malignant pressure which strains they're poor puny plastic body's. The poor old pump under pressure continually is like us having eaten too much, too full, tummy bloated and achy, pills, Galvascon and Magnesia have no effect, your in a perpetual state of ache and even nausea, can't settle, waddling about clutching yer tum forever and ever. That's how the water pump must feel.

[Greylady2]

Why not just switch the pump off overnight, all those little burps are using the battery.

Fresh water pumps last much longer if switch off when they're not going to be used for some time, and some water run off at a tap to relieve it of the malignant pressure which strains they're poor puny plastic body's. The poor old pump under pressure continually is like us having eaten too much, too full, tummy bloated and achy, pills, Galvascon and Magnesia have no effect, your in a perpetual state of ache and even nausea, can't settle, waddling about clutching yer tum forever and ever. That's how the water pump must feel.

Yes i guess it a tough life, lets hope we dont come back as one hey Bizzard.

[bizzard]

Yes i guess it a tough life, lets hope we dont come back as one hey Bizzard.

I'd like to come back as a whale. pump.

Edited November 25, 2016 by bizzard

[Greylady2]

That looks good. Now we need a cool night and see what that pump does.

 

Greylady how difficult is it to see which model the water pump is. Think you will need to lift the board above it if that is possible.

Yer fingers crossed.

 

Here is my water pump, it took me 13 hours to empty the cupboard of cleaning 'gear'.

 

Ow Hang on !

 

That say 25psi on it and thats what the pressure read before i pumped it up.

 

:-(

Edited November 25, 2016 by Greylady2

[Geo]

Greylady, Just a thought could you open the cold tap run a little water, turn it off and when the pump stops, turn the pump off and open the cold tap. Does any water come out, none, a little or about 1/2 a litre or more.

 

Many thanks for the photo

Edited November 25, 2016 by Geo

[Greylady2]

 

Greylady, Just a thought could you open the cold tap run a little water, turn it off and when the pump stops, turn the pump off and open the cold tap. Does any water come out, none, a little or about 1/2 a litre or more.

One mo i will di it now.

Right am getting no water at all not a drop.

 

Bugger.

[Geo]

Yer fingers crossed.

 

Here is my water pump, it took me 13 hours to empty the cupboard of cleaning 'gear'.

 

Ow Hang on !

 

That say 25psi on it and thats what the pressure read before i pumped it up.

 

:-(

 

 

Heck only 13 hours, that is better than mine. I daren't open the doors it would fill the kitchen as it rushed to get free.

 

Many thanks for the photo

One mo i will di it now.

Right am getting no water at all not a drop.

 

Bugger.

 

OK so that as expected is the same.

 

Now we wait for over night.

[bizzard]

Incidentally. Never leave the water pump switched on if leaving the boat unattended for any length of time. You might return to find the boat flooded out because a leak has sprung in the pressurized system. Two boats I've had to do flood repairs, replace the bathrooms and kitchens rotted floors for folk who'd left them on.

[Greylady2]

Heck only 13 hours, that is better than mine. I daren't open the doors it would fill the kitchen as it rushed to get free.

 

Many thanks for the photo

 

OK so that as expected is the same.

 

Now we wait for over night.

Bbbbrrrr lol

[Greylady2]

Now i am genuinely worried i have put 38 psi in my pressure vessel when the water pump is rated 25psi.

 

I best turn the water off i cant afford a leak.

 

:-((((

[mross]

Don't worry, you have not done any harm by pressurising the expansion tank, The expansion tank, plumbing and calorifier are built to withstand the pressure quoted on the expansion tank, The pump is too but won't pump as high.