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Just now, cutandpolished61 said:

Good morning All,

 

i noticed for some time that my water pump comes on every 4-5 hours for just 1 second.

I checked several times for leaks but found none and the bilge is dry.

Is my pump on her way out?

 

I am not sure that is particularly unusual but does indicate your system has a slight leak if it does it during the day. If it is at night its probably the calorifier cooling down so normal. It will be more pronounced if you have no accumulator and running for just one second suggest that you do not. If you do have one then check its air pressure but do not confuse it with an identical or assimilate object that is an expansion vessel. They are in different parts of the water system and have different air pressures.

 

Now possible very small leaks - dripping tap/shower, leaking PRV, leaking valves in the pump (you have at least six vales in most cases), leaking plumbing joint and as you say the bilge is dry possibly on the hot part of the plumbing close to the calorifier so a small weep evaporates rather than dripping into the bilge.

 

As long as the bilge is dry I would suggest that you "hide" the problem by fitting an accumulator if you do not already have one. Just ask for more info if you need it.

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1 hour ago, cutandpolished61 said:

Good morning All,

 

i noticed for some time that my water pump comes on every 4-5 hours for just 1 second.

I checked several times for leaks but found none and the bilge is dry.

Is my pump on her way out?

There is still a lot of virus about, you should be washing your hands at least once every three hours, that should solve the problem ?.

 

1 second every 5 hours is a tiny leak, could even be the valves in the pump, but as Tony said, its probably just some hot water cooling down.

 

............Dave

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If you're listening to the pump for signs of a leak then it's much easier to diagnose if you can isolate your accumulator. I installed mine with an isolator valve.

 

As Tony says it could be the PRV from the accumulator tank leaking (assuming you have one). If it's connected to a skin fitting on the outside of the boat check if that's wet. If so give the PRV a couple of twists to dislodge any limescale build up to see if that helps. Do you have a hot water expansion tank fitted?

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4 hours ago, blackrose said:

If you're listening to the pump for signs of a leak then it's much easier to diagnose if you can isolate your accumulator. I installed mine with an isolator valve.

 

As Tony says it could be the PRV from the accumulator tank leaking (assuming you have one). If it's connected to a skin fitting on the outside of the boat check if that's wet. If so give the PRV a couple of twists to dislodge any limescale build up to see if that helps. Do you have a hot water expansion tank fitted?

If the OP has an accumulator then it needs repressurizing (air pressure). it takes a lot longer than one second to refill and pressurise an accumulator.

 

The expaniosn tank will only make a minimal difference because its only accommodating the expanding hot water so a soon as any is drawn off it just sits there until the water in the calorifier is heated again. Its the accumulator that makes most difference because it will contain several litres of water that will "make up" for the supposed leak (I don't think there is one as the OP has not been back) to give more info re accumulator etc.).

 

Not all PRVs vent to a skin fitting, many just vent into a bilge, mine vented back to the inlet side of the pump so it did not waste water.

 

Actually we are all assuming a calorifier, this may have an instant gas water heater.

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30 minutes ago, cutandpolished61 said:

Sorry Alastair, i don't know how to do that without creating a mess. Need to check the manual. It's an ITT accumulator and i can see a screw on top of the cylinder. 

No mess at all, its just the air valve on top not a water connection.

TD'

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And you can measure the pump cut out pressure by using a car tyre gauge on that valve with the pump on and not running. You can measure the air pressure in the accumulator in the same way but with the pump off and a tap open. The air pressure should be about half the pump cut out pressure. I bet its far, far less. f water comes out of that valve you need a new accumulator.

 

Do the air pressure test first and if it not al least 10psi pump it up to that value and then do the rests and adjust the air pressure to suit.

 

Make sure it is an accumulator in a COLD pipe and not an expansion vessel in a HOT pipe.

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  • 4 weeks later...
On 06/07/2020 at 14:08, Tracy D'arth said:

No mess at all, its just the air valve on top not a water connection.

TD'

So i opened the air valve and water came out straight away. But no improvement at all. It got worse over the last 2 weeks. When i open the tap fully the pump comes on directly and runs continuously until i close the tap. But with a slightly opened tap and little flow of water the pump works on a second basis on - off - on - off until the tab is closed again. I have no knowledge in plumbing and struggle to figure out what is going on.

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2 minutes ago, cutandpolished61 said:

So i opened the air valve and water came out straight away. But no improvement at all. It got worse over the last 2 weeks. When i open the tap fully the pump comes on directly and runs continuously until i close the tap. But with a slightly opened tap and little flow of water the pump works on a second basis on - off - on - off until the tab is closed again. I have no knowledge in plumbing and struggle to figure out what is going on.

The accumulator is knackered, bladder busted. Fit a new one.

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What Tracy said.

If the accumulator was working you would get this pattern:

Open tap - water flows. After a delay, pump runs. If tap is only opened slightly, pump will cut out after a short run and water continues to flow. 

If you open the tap fully, water flows, pump comes on after shorter delay and continues briefly after you turn tap off. 

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4 minutes ago, Alastair said:

What Tracy said.

If the accumulator was working you would get this pattern:

Open tap - water flows. After a delay, pump runs. If tap is only opened slightly, pump will cut out after a short run and water continues to flow. 

If you open the tap fully, water flows, pump comes on after shorter delay and continues briefly after you turn tap off. 

not quiet. Accumulators only alter the cycling frequency of the pump so with lower than pump delievry flow rates from the tap the pump is still likely to cycle with the longer the tap is open the more likely you will get more than one on-off cycle before you close the tap.

 

Apart from the fact the pump may still cycle Alastair's description is correct.

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9 minutes ago, cutandpolished61 said:

Thanks all. So I will have to replace the accumulator as the pump comes on as soon as I open the tap.

If you are happy for the pump to run for a moment every 4 or 5 hours hen no you do not have to replace the accumulator. If you want to stop that and extend the cycling frequency the yes you do.

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