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I have a 70' boat with water pump & acc tank residing in the bows near the water tank. My shower is midships, and by the time I have pumped water down to the calorifier in the engine bay and back to the shower I get a problem: the water pump never quite reaches its cutoff pressure due to the length of the pipe run. As a result of this the pump trips, meaning whoever is in the middle of having her their extended luxury shower needs to get out of the shower and 'untrip' the pump.

 

Any thoughts on whether putting a second pump near the calorifier on the hot water 'out' will address this problem? It will be on the same loop as the first pump, not a separate loop.

Edited by Boomslang
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Just now, Boomslang said:

I have a 70' boat with water pump & acc tank residing in the bows near the water tank. My shower is midships, and by the time I have pumped water down to the calorifier in the engine bay and back to the shower I get a problem: the water pump never quite reaches its cutoff pressure due to the length of the pipe run.

 

Any thoughts on whether putting a second pump near the calorifier on the hot water 'out' will address this problem? It will be on the same loop as the first pump, not a separate loop.

You have some problem somewhere with your set up, not the pump unless its a very small one? what pump is it? I had twin pumps on my 70 footer and removed one and it worked better. My present tiny 68 footer has one pump and brulliant pressure everywhere on the boat including bathroom amidships and stern utility room with washing machine.

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if you mean the circuit breaker trips. It is possible you have:

 

1.Undersized wiring for the length of run.

2.Poor electrical connections

3.Voltage drop somewhere along the cabling

4.Faulty pump

 

Caveat:I have had a few beers so I may be talking crap.

Edited by rusty69
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1 minute ago, rusty69 said:

if you men the circuit breaker trips. It is possible you have:

 

1.Undersized wiring for the length of run.

2.Poor electrical connections

3.Voltage drop somewhere along the cabling

4.Faulty pump

 

Caveat:I have had a few beers so I may be talking crap.

You always talk crap ?

I agree though, is it skinny cables causing the doobrey to trip? or precsiely what does the OP mean?

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1 hour ago, Boomslang said:

I have a 70' boat with water pump & acc tank residing in the bows near the water tank. My shower is midships, and by the time I have pumped water down to the calorifier in the engine bay and back to the shower I get a problem: the water pump never quite reaches its cutoff pressure due to the length of the pipe run. As a result of this the pump trips, meaning whoever is in the middle of having her their extended luxury shower needs to get out of the shower and 'untrip' the pump.

 

Any thoughts on whether putting a second pump near the calorifier on the hot water 'out' will address this problem? It will be on the same loop as the first pump, not a separate loop.


Your description doesn't add up to me.

If you are trying to push through more pipe and constrictions than in a shorter boat, then the pump will surely reach its cut off pressure sooner because it can't shift the water down the pipework fast enough.
 

After all if you take the most extreme case and cut all the taps off to give zero flow it will quickly reach its cut off pressure and shut down.  How can your pump not be reaching its cut off pressure?

As someone else asks what do you actually mean by "the pump trips"?

A pump shouldn't "trip" if you shut all the taps, of if you close one to nearly shut, so why should it just because of a long pipe run?

I don't think you are using the right words to describe the issues you are having,and without a beter description, I doubt anybody can give you the right advice.
 

Edited by alan_fincher
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1 hour ago, rusty69 said:

if you mean the circuit breaker trips. It is possible you have:

 

1.Undersized wiring for the length of run.

2.Poor electrical connections

3.Voltage drop somewhere along the cabling

4.Faulty pump

 

Caveat:I have had a few beers so I may be talking crap.


Why would any of 1 to 3 cause a circuit bereaker to trip, though? All would surely resut in less current passing through a circuit breaker than was intended - definitely not more current.

EDIT:  I missed the "beers" bit of your post!  You might not have come up with the first three items had you not drunk those beers!

Edited by alan_fincher
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18 minutes ago, alan_fincher said:


Why would any of 1 to 3 cause a circuit bereaker to trip, though? All would surely resut in less current passing through a circuit breaker than was intended - definitely not more current.

EDIT:  I missed the "beers" bit of your post!  You might not have come up with the first three items had you not drunk those beers!

 

If you reduce the voltage and thus current that can be pushed through most motors the motor speed drops. This reduces the internal varying magnetic fluxes that in turn have the effect of reducing the motor's apparent "resistance" so the current rises. A very common problem on water pumps.

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44 minutes ago, alan_fincher said:

Why would any of 1 to 3 cause a circuit bereaker to trip, though? All would surely resut in less current passing through a circuit breaker than was intended

Nope, the opposite. Greater resistance causes a lower voltage at the pump which in turn (a motor is a largely reactive device, not a resistive one) will cause the current to rise. 


Oh, Tony B beat me to it. 

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4 hours ago, Boomslang said:

I have a 70' boat with water pump & acc tank residing in the bows near the water tank. My shower is midships, and by the time I have pumped water down to the calorifier in the engine bay and back to the shower I get a problem: the water pump never quite reaches its cutoff pressure due to the length of the pipe run. As a result of this the pump trips, meaning whoever is in the middle of having her their extended luxury shower needs to get out of the shower and 'untrip' the pump.

 

Any thoughts on whether putting a second pump near the calorifier on the hot water 'out' will address this problem? It will be on the same loop as the first pump, not a separate loop.

My 70' Orion came (not new) with two pumps and two accumulators, one on the hot water circuit and one on the cold.

 

They manage the shower comfortably, I did contemplate changing them for one larger pump (to save replacement costs) but instead I stopped buying Sureflo and left the double arrangement alone.

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9 hours ago, Tony Brooks said:

 

If you reduce the voltage and thus current that can be pushed through most motors the motor speed drops. This reduces the internal varying magnetic fluxes that in turn have the effect of reducing the motor's apparent "resistance" so the current rises. A very common problem on water pumps.

 

8 hours ago, WotEver said:

Nope, the opposite. Greater resistance causes a lower voltage at the pump which in turn (a motor is a largely reactive device, not a resistive one) will cause the current to rise. 


Oh, Tony B beat me to it. 

 

Fair enough!

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11 hours ago, Boomslang said:

I get a problem: the water pump never quite reaches its cutoff pressure due to the length of the pipe run.

 

As Alan points out earlier, this does not follow. If the pipe run was too long (i.e. of too high resistance), the pump would reach its cut-off pressure very easily and simply cycle on and off repeatedly, perfectly happily. 

 

As others have also said, the cable feeding the pump is probably inadequate, but no-one so far has told you how to prove it. Start the shower, then use a multimeter to measure the voltage at the pump terminals while the pump is running. It needs to be 12.0v or higher. I predict you'll find a value of perhaps 10v or possibly a lot less, confirming the diagnosis.

 

The fault is probably cables too thin, but might just be a high resistance switch of cable joint somewhere.

 

Do report back what you find...

 

 

 

 

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12 hours ago, Boomslang said:

I have a 70' boat with water pump & acc tank residing in the bows near the water tank. My shower is midships, and by the time I have pumped water down to the calorifier in the engine bay and back to the shower I get a problem: the water pump never quite reaches its cutoff pressure due to the length of the pipe run. As a result of this the pump trips, meaning whoever is in the middle of having her their extended luxury shower needs to get out of the shower and 'untrip' the pump.

 

Any thoughts on whether putting a second pump near the calorifier on the hot water 'out' will address this problem? It will be on the same loop as the first pump, not a separate loop.

Is this a new (to you) boat ?

Has it always done this ?
Is it a recent development ?

Are you plugged into a 'mains' electric supply  with the battery charger 'on' ?

Edited by Alan de Enfield
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6 minutes ago, Tony Brooks said:

Could even be flat batteries - what happens with the engine running at 1200 rpm?

 

Yes I totally overlooked this!

 

Lets do it a step at a time. First, we need to find out the terminal voltage on the water pump under whatever conditions the tripping occurs. Then we can confirm the diagnosis of low pump voltage, or rule it out. 

 

Once we know the pump terminal voltage when the fault is happening, we can go forward without running up blind alleys. 

 

 

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8 hours ago, frahkn said:

My 70' Orion came (not new) with two pumps and two accumulators, one on the hot water circuit and one on the cold.

 

I too have an Orion boat and just because Richard did weird things like this, it does not necessarily make them a Good Idea!!!

 

 

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I don't understand.

On our boat (with nice big accumulator), we start the shower and the pump pumps at 11 litres a minute and water comes out of the shower at 11 litres a minute so the pump runs all the time. The shower is turned off and the pump runs until the pressure builds in the accumulator to the set point and the pump stops.

Siimples!

A few years back we had problems with our water pump tripping the switch on the panel ....a bugger to sort out....but it turned out to be a switch panel problem solved by disconnecting the switch panel -ve (to provide the circuit for the warning lights). Never had a problem since.

Sounds to me that the OPs pump circuit is tripping because of some sort of issue like this and 'extended running' of the pump is causing a trip.....nothing to do with the pressure. Switch panel issue, old pump, crap pump etc.

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1 minute ago, Dr Bob said:

I don't understand.

On our boat (with nice big accumulator), we start the shower and the pump pumps at 11 litres a minute and water comes out of the shower at 11 litres a minute so the pump runs all the time. The shower is turned off and the pump runs until the pressure builds in the accumulator to the set point and the pump stops.

Siimples

You obviously have no instantaneous water heater. 

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1 hour ago, Mike the Boilerman said:

 

I too have an Orion boat and just because Richard did weird things like this, it does not necessarily make them a Good Idea!!!

 

 

You absolutely don't need to tell me about Richard's eccentricities!!!  Last winter I paid an arm and a leg (probably some other bits as well) to have Debdale move my engine to a more sane position in the boat. Water pump weirdness is (more or less) the least of my worries.?

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36 minutes ago, rusty69 said:

You obviously have no instantaneous water heater. 

No one...........has an instantaneous water heater.

To raise the temperature of a water molecule one has to expose that molecule to heat and it takes a finite time for even the littlest amount of heat to transfer into said molecule of water. That 'finite time' means it can never be instantaneous - maybe instantaneous plus a little bit??‍?

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