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Poppin

Water pump woes

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Right... So for a while I have been suffering with poor water pressure and various other problems. My shurflo started leaking so I decided to try a quick pump swap to see if it solved everything. 

 

I changed it for a Jabsco par max 3.5 (seriously LOUD pump!), and while everything was disconnected I also opened the sediment prefilter under the sink. The filter element was so clogged up that I decided to order a new one and, meanwhile, just put the filter housing back together without the element.

 

I have a strange situation now. The pressure in most of the taps is fine. However the kitchen sink taps (closest to the pump), have terrible pressure and the pump basically goes on and off pushing out a poor, pulsating flow. This doesn't happen with the other taps. I have tried sucking on the mixtap in case of air lock. I have noticed a slow drip from the mixtap which I'm not sure is related. I will turn off the pump and inspect the washers.

 

Furthermore, the old pump would pre-fill the calorifier until pressurised when the hot taps have been open. This pump does not, and simply pushes hot water through in a similar on/off fashion as the kitchen taps.

 

I don't particularly miss the pressurising into the expansion tank that used to happen, because it would always be like stored cold water that I would need to get out of the tap before the hot came through. I could never figure out this problem either. 

 

Anyway, I have found the screw under the cover on the new pump that I imagine is a pressure or cut in adjuster. Can someone confirm this and how it works or if it's even part of the solution!?

 

Any advice is much appreciated!

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3 minutes ago, Poppin said:

I have a strange situation now. The pressure in most of the taps is fine. However the kitchen sink taps (closest to the pump), have terrible pressure and the pump basically goes on and off pushing out a poor, pulsating flow. This doesn't happen with the other taps. I have tried sucking on the mixtap in case of air lock. I have noticed a slow drip from the mixtap which I'm not sure is related. I will turn off the pump and inspect the washers

Long shot.You haven't got one of those silly filter things on the tap? if so, try removing it and or cleaning it

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Check the pump cut in pressure and ensure the accumulator is set to the same pressure or a tiny bit more. I think your new pump is a different setting to the old one and may be causing problems.  Or it may be that your accumulator has gone a bit flat over time.

 

I also bet your mixer tap swirl unit ( the plastic vanes at or in the end) are bunged up with crud.

 

N

 

 

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1 minute ago, BEngo said:

also bet your mixer tap swirl unit ( the plastic vanes at or in the end) are bunged up with crud.

That's the thing I was talking about,but didn't know what it was called....

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1 minute ago, rusty69 said:

That's the thing I was talking about,but didn't know what it was called....

but some taps do have filters where the water goes in as well

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Or a little gauze filter in the tap spout, just dig it out and chuck it. Ceramic valve taps almost invariably have them.

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4 hours ago, BEngo said:

Check the pump cut in pressure and ensure the accumulator is set to the same pressure or a tiny bit more. I think your new pump is a different setting to the old one and may be causing problems.  Or it may be that your accumulator has gone a bit flat over time.

 

I also bet your mixer tap swirl unit ( the plastic vanes at or in the end) are bunged up with crud.

 

N

 

 

From what I gather, the new pump.is supposed to cut in at 15psi. How do I check the expansion tanks pressure? Do simply put a gauge on the Schrader valve on top? Or do I need to disconnect from calorifier first? Can it be pressurised with a simple bicycle pump!? I thought perhaps it takes its pressure from the calorifier.

 

Is there any reason why the expansion vessel is fitted to a pipe that enters the calorifier at the bottom? Since hot water rises I would have thought higher up would make more sense? Can someone explain this to me? Here are some pics:

 

 

IMG_20181130_155215512.jpg

IMG_20181130_155204949.jpg

IMG_20181130_155608213.jpg

IMG_20181130_155346151.jpg

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Attach a car or bicycle pump with a pressure gauge included.

Switch of the water pump and drain the pressure.

Read the pressure, for a 1.5 bar pump the air precharge should be about 0.8 to 1.0 bar. If yours is at the domestic heating precharge , as shown on the label, it will do nothing at a lower system pressure

1 bar is 14.7 psi approx.

Pump up to this and try the pump. The pressure will rise as the air inside the rubber bag in the expansion vessel is squeezed. 

Switch off and drain again, if the gauge pressure drops to zero the rubber bag is US.

Plenty of suppliers for vessels, can be bought at good plumbing suppliers but need to be potable water grade no the very cheap central heating steel body without internal finish.

It does not matter at what point the vessel is connected, it is there to store water under pressure although the cold side is better

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3 minutes ago, adrianh said:

Attach a car or bicycle pump with a pressure gauge included.

Switch of the water pump and drain the pressure.

 

Do you mean switch off the pump and then drain the pressure from the calorifier?

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Just realised you said 1.5 bar cut in therefore probably a 2.5 bar pump hence precharge at 1.8 to 2.0 bar.

Yes re pressure drainage

Edited by adrianh

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11 hours ago, Poppin said:

Do you mean switch off the pump and then drain the pressure from the calorifier?

Despite his answer I very much doubt Adrianh meant drain the calorofier. Just turn the pump on and open a tap. When the tap stops running the WATER pressure in the system has gone so you are just left with air pressure in the calorifier

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Without having fully read the thread I would just repeat that an expansion as opposed to an accumulator vessel must be on the hot side rather than the cold side if a non-return valve is present in the calorifier pipework. (eg SureCal calorifiers) Probably not relevant to the OP but might be to some newbie reading this.

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6 minutes ago, system 4-50 said:

Without having fully read the thread I would just repeat that an expansion as opposed to an accumulator vessel must be on the hot side rather than the cold side if a non-return valve is present in the calorifier pipework. (eg SureCal calorifiers) Probably not relevant to the OP but might be to some newbie reading this.

Presuming the cold input to the calorifier is at the bottom and the hot output is at the top (am I right?), What I have is an isolation valve, followed by what looks like a non-return valve, followed by a T that leads to the expansion vessel, and then the calorifier. Does this mean I have an accumulator rather than an expansion vessel? Expansion vessels provide somewhere for expanding water pressure to go as it heats up, so if it were an expansion vessel it would be pushing the lower down water into the vessel, is this right?

 

Is this tank being used as an expansion vessel? I'm wondering if fitting a separate accumulator closer to the pump would help my problems too.

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So could this be my problem... The old shurflo I took out was a 30 psi pump, the Jabsco 3.9 I put in (whilst being 13 litres/min and horribly loud) is only 25psi. 

 

The pressure problems I've had since getting this boat could be due to the fact that 30psi wasn't enough to begin with. The water has to travel a good 45 feet to the calorifier. But at least it was enough to charge the calorifier. 25psi now just doesn't cut it, so I'm left with a very poor flow, both because the new pump isn't charging the calorifier AND because it's cut in pressure is too low causing it to cut in and out. 

 

Perhaps if I went for a 45psi pump (and pumped up the expansion vessel to match this), and perhaps also got an accumulator to go next to It to smooth things out?

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12 minutes ago, Poppin said:

So could this be my problem... The old shurflo I took out was a 30 psi pump, the Jabsco 3.9 I put in (whilst being 13 litres/min and horribly loud) is only 25psi. 

 

The pressure problems I've had since getting this boat could be due to the fact that 30psi wasn't enough to begin with. The water has to travel a good 45 feet to the calorifier. But at least it was enough to charge the calorifier. 25psi now just doesn't cut it, so I'm left with a very poor flow, both because the new pump isn't charging the calorifier AND because it's cut in pressure is too low causing it to cut in and out. 

 

Perhaps if I went for a 45psi pump (and pumped up the expansion vessel to match this), and perhaps also got an accumulator to go next to It to smooth things out?

Jabsco 3.5 or 3.9. If you go for a 45 psi pump, that may be too close to the calorifier prv pressure rating.

 

We have a jabsco 2.9 which happily works on a calorfier at greater distance than 45 foot at a reasonable flow rate.

 

What spec was the shurflo you replaced? Have you adressed the kitchen tap low flow rate, checked for blockages in filters/strainers, semi closed valves etc?

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18 minutes ago, Poppin said:

the Jabsco 3.9 I put in (whilst being 13 litres/min and horribly loud) is only 25psi. 

I also have a Jabsco Par-Max 3 (13 litres).

I don't have any of the problems you are highlighting and it is happily feeding 2-showers & 2 wash basins (in the bathrooms) + a shower in the 'en-suite' shower room), plus the Kitchen sink, plus the calorifier.

The water tank is in the keel and so probably has to overcome a lift of 4 or 5 feet as well.

 

I have a second identical pump as a 'deck-wash' and that is lifting water (probably) 10 feet and pumping out via the deck hose with plenty of power.

 

I don't think your pump is the problem - maybe incompatability with the rest of the system, or, as suggested, a problem with the expansion vessel / accumulator

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22 hours ago, Poppin said:

Right... So for a while I have been suffering with poor water pressure and various other problems. My shurflo started leaking so I decided to try a quick pump swap to see if it solved everything. 

 

I changed it for a Jabsco par max 3.5 (seriously LOUD pump!), 

 

I have a Jabsco Parmax 3.5 and it's not particularly loud. 

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2 hours ago, Poppin said:

Presuming the cold input to the calorifier is at the bottom and the hot output is at the top (am I right?), What I have is an isolation valve, followed by what looks like a non-return valve, followed by a T that leads to the expansion vessel, and then the calorifier. Does this mean I have an accumulator rather than an expansion vessel? Expansion vessels provide somewhere for expanding water pressure to go as it heats up, so if it were an expansion vessel it would be pushing the lower down water into the vessel, is this right?

 

Is this tank being used as an expansion vessel? I'm wondering if fitting a separate accumulator closer to the pump would help my problems too.

That order makes it an expansion vessel so pressurise to pump cut out pressure.

 

If, and I mean IF it was pressurised to the pump cut in pressure then it would act as an accumulator cum expansion vessel for hot water only but with a reduced expansion volume.

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1 hour ago, Poppin said:

So could this be my problem... The old shurflo I took out was a 30 psi pump, the Jabsco 3.9 I put in (whilst being 13 litres/min and horribly loud) is only 25psi. 

 

The pressure problems I've had since getting this boat could be due to the fact that 30psi wasn't enough to begin with. The water has to travel a good 45 feet to the calorifier. But at least it was enough to charge the calorifier. 25psi now just doesn't cut it, so I'm left with a very poor flow, both because the new pump isn't charging the calorifier AND because it's cut in pressure is too low causing it to cut in and out. 

 

Perhaps if I went for a 45psi pump (and pumped up the expansion vessel to match this), and perhaps also got an accumulator to go next to It to smooth things out?

You mention the pump is loud? How have you mounted it and what onto? Have you got fully flexible inlet and outlet pipes from and to the pump etc?

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1 hour ago, Poppin said:

So could this be my problem... The old shurflo I took out was a 30 psi pump, the Jabsco 3.9 I put in (whilst being 13 litres/min and horribly loud) is only 25psi. 

 

The pressure problems I've had since getting this boat could be due to the fact that 30psi wasn't enough to begin with. The water has to travel a good 45 feet to the calorifier. But at least it was enough to charge the calorifier. 25psi now just doesn't cut it, so I'm left with a very poor flow, both because the new pump isn't charging the calorifier AND because it's cut in pressure is too low causing it to cut in and out. 

 

Perhaps if I went for a 45psi pump (and pumped up the expansion vessel to match this), and perhaps also got an accumulator to go next to It to smooth things out?

 

I don't understand where this "not charging the calorifier" comes from. If you have 25 psi pressure then that pressure will force water into the calorifier (with the hot taps open) and air out of the taps. If it does not and the calorifier remains empty then there must be something blocking the flow - either into the pump or between pump - calorifier - open taps.

 

The noise make me suspect its on the inlet side of the pump and that will also cause a poor flow.

 

Although flow from an outlet will be proportional to pressure the more important data is the delivery rate of the pump (litres per min).  Have you given us the flow rate of the old pump? Its not in the above. If the new pump output (l/m) is more than the old one then you are looking at undersized pipes for the run length or a physical deliberate or accidental blockage.

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29 minutes ago, Tony Brooks said:

That order makes it an expansion vessel so pressurise to pump cut out pressure.

 

If, and I mean IF it was pressurised to the pump cut in pressure then it would act as an accumulator cum expansion vessel for hot water only but with a reduced expansion volume.

So you're saying that reducing the pressure to the pump cut in will make it BOTH an expansion vessel and an accumulator? Though with less expansion capacity...

 

24 minutes ago, mrsmelly said:

You mention the pump is loud? How have you mounted it and what onto? Have you got fully flexible inlet and outlet pipes from and to the pump etc?

No the pre-existing outlet and inlet pipes are copper. I can quite easily replace with flexile hose if this will reduce the noise.

 

24 minutes ago, Tony Brooks said:

 

Although flow from an outlet will be proportional to pressure the more important data is the delivery rate of the pump (litres per min).  Have you given us the flow rate of the old pump? Its not in the above. If the new pump output (l/m) is more than the old one then you are looking at undersized pipes for the run length or a physical deliberate or accidental blockage.

I think we may have found the problem here. The last pump was something like 10 litres/min. The 45ft run (one way) is only 15mm speedfit pipe (and some copper). Since this pump is more litres/min could this be causing my pressure and noise problems? 

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1 minute ago, Poppin said:

So you're saying that reducing the pressure to the pump cut in will make it BOTH an expansion vessel and an accumulator? Though with less expansion capacity...

Yes, that’s what he’s saying. It’s more usual to have two vessels, each performing their own function. That way both are optimised for their function. 

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1 minute ago, Poppin said:

So you're saying that reducing the pressure to the pump cut in will make it BOTH an expansion vessel and an accumulator? Though with less expansion capacity...

 

No the pre-existing outlet and inlet pipes are copper. I can quite easily replace with flexile hose if this will reduce the noise.

 

I think we may have found the problem here. The last pump was something like 10 litres/min. The 45ft run (one way) is only 15mm speedfit pipe (and some copper). Since this pump is more litres/min could this be causing my pressure and noise problems? 

1. Yes, but there is no point in doing it. If it is on the calorifier side of a NRV then it was probably intended to be an expansion vessel but it would act as an accumulator for the HOT water system only if pressurised differently. This will not cure your problem.

 

2. Flexible hose direct to the pump will quieten it to some degree a swill ensuring the screws in its rubber mounting feet are just about "nipped up".

 

3. A higher output pump should not cause low pressure but a lower cut out pressure will. I still suspect the noise may be caused by a restriction on the inlet side and that would contribute to your problems. It would also give a low flow rate on the old pump.

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22 minutes ago, Poppin said:

 

 

No the pre-existing outlet and inlet pipes are copper. I can quite easily replace with flexile hose if this will reduce the noise.

 

 

Replacing with flexible hose will greatly reduce the noise and also be better for the pump housing as copper is far too rigid. I also have in the past mounted onto a wooden board and then onto rubber mounts/bobbins this again helps a lot. Ebay is your friend for the fittings.

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