What size water pump ?

[Badger]

I have fitted to my boat Shurflo pump for the fresh water taps and shower. This works in conjunction with an accumulator at about 15psi . The pump is now 15 years old. My partner and I can both remember the shower in the early days having really good pressure. Now though the shower flow seems well, adequate at best. Could it be that the pump is past it's best, do they become weaker with age ?. The pump is rated at 11.3 litres per minute. Is this big enough, I see you can buy pumps with a greater flow rate...what size is yours !. Any advice would be much appreciated.

 

Badger

[ditchcrawler]

Does the pump cut in and out while you are showering or does it run continuously. If it cuts out it could be the pressure switch has gone out of calibration.

[bottle]

Could be furred pipe work.

[Alan de Enfield]

We have a Par-Max-3.5 which is 13 litres per minute.

 

It feeds 2 bathrooms, a shower room, and the galley.

 

We also have a Par-Max 2.9 which is 11 litres per minute - this feeds the deck wash and gives a good forceful jet on the hose pipe.

[Tony Brooks]

If it runs all the time it could be faulty valves in some of the pumping chambers reducing its output volume.

[Alan Saunders]

Cleaning your shower head may solve the problem. On the 'rubbery' ones just rub the surface, some solid ones can be dismantled and the hard water deposits scraped out, some may need each individual hole to be probed. Use something that will not damage the jets, like a wooden cocktail stick. Turn the shower on and the loosened calcium will be ejected. For a perfect job immerse the shower head or, better, its parts in a warm solution of kettle descaler acid.

 

Even in hard water areas many people are unaware of the need to decalcify the shower head. e.g. In London and Portsmouth my kettle and shower would build a serious crust of chalk within a few months; where I am now both have minimal deposits. If you are used to soft water you may be particularly unaware of this problem.

 

My cheap, plastic shower head produced literally stinging jets from an old Shurflo pump. I have throttled it back to a more gentle but adequate spray which also uses less water. Under the cover of my cheap, thermostatic shower valve each inlet (hot & cold) has a (ball?) valve operated by a screwdriver slot.

 

There was a free kit available to measure the flow rate of your shower. It consisted of a calibrated plastic bag to measure the flow-rate and a valve to limit the flow if it was found to be more than advised/recommended.

 

HTH, Alan

[Badger]

Thanks for your replies. When we shower the pump runs constantly...it would, wouldn't it ?. I checked the pressure in the accumulator...about 15psi, and the pump is cutting out at around 32psi (as it should ). I did think about furring of the pipes (which are all plastic ). Can plastic pipes fur up ?. I have seen no evidence of furring. I was wondering if the pump is not pumping as it did when new. The diaphragms appear good...the pump had a new front end kit about ten years ago I think. Does anybody know if these pumps do deteriate after long period of use.

 

Badger

Cleaning your shower head may solve the problem. On the 'rubbery' ones just rub the surface, some solid ones can be dismantled and the hard water deposits scraped out, some may need each individual hole to be probed. Use something that will not damage the jets, like a wooden cocktail stick. Turn the shower on and the loosened calcium will be ejected. For a perfect job immerse the shower head or, better, its parts in a warm solution of kettle descaler acid.

 

Even in hard water areas many people are unaware of the need to decalcify the shower head. e.g. In London and Portsmouth my kettle and shower would build a serious crust of chalk within a few months; where I am now both have minimal deposits. If you are used to soft water you may be particularly unaware of this problem.

 

My cheap, plastic shower head produced literally stinging jets from an old Shurflo pump. I have throttled it back to a more gentle but adequate spray which also uses less water. Under the cover of my cheap, thermostatic shower valve each inlet (hot & cold) has a (ball?) valve operated by a screwdriver slot.

 

There was a free kit available to measure the flow rate of your shower. It consisted of a calibrated plastic bag to measure the flow-rate and a valve to limit the flow if it was found to be more than advised/recommended.

 

HTH, Alan

At the weekend I fitted a new shower rose, but this also made no difference.

[MtB]

Can plastic pipes fur up ?

 

 

Quick answer? No.

 

What can fur up though is the heat exchanger in a gas water heater. How do you get your hot water?

 

My money is on it being the shower head, despite your comment about having changed it. Different shower heads provide a huge range of different flow rates.

 

Take care not to confuse 'flow' with 'pressure'. Different parameters meaning different things to technical peeps.

 

Try measuring the flow rate (use a bucket and a stopwatch) with the shower head removed i.e. from an open-ended hose, then again with the head put back on.

[Tony Brooks]

Thanks for your replies. When we shower the pump runs constantly...it would, wouldn't it ?.

 

Not necessarily. If the pump output volume is higher than that exiting the shower the pump will cycle (turn on and off). If the volume that could flow from the shower is morel than the volume being delivered by the pump the pressure will drop to a degree and the pump will run continuously.

 

The more restricted (read furred) the flow through the system is the more likely the pump is to cycle so with theses symptoms I suspect it is lack of pump delivery volume but we really need to know more about the hitsory and the system you are using.

[ditchcrawler]

 

Not necessarily. If the pump output volume is higher than that exiting the shower the pump will cycle (turn on and off). If the volume that could flow from the shower is morel than the volume being delivered by the pump the pressure will drop to a degree and the pump will run continuously.

 

 

As mine does because the pump can supply more water than the shower delivers.

[MtB]

My water pump cycles On and OFF while the shower is in use.

In fact the reason yours doesn't could be that the shower is demanding more than the pump can deliver. This suggests the pump is at fault.

 

Have you measured the flow rate as I suggested earlier? try it at both a fully open cold tap, and at the shower with and without the handset attached to the hose. Post the results back on here...

[Badger]

My water pump cycles On and OFF while the shower is in use.

In fact the reason yours doesn't could be that the shower is demanding more than the pump can deliver. This suggests the pump is at fault.

 

Have you measured the flow rate as I suggested earlier? try it at both a fully open cold tap, and at the shower with and without the handset attached to the hose. Post the results back on here...

Yes that's a good simple test...pity I did not think of it when we were on the boat at the weekend. I will try a bucket test next visit. ...MANY THANKS

 

Badger

[Badger]

just back from boat ...as Boilerman suggested, tested volume of water pumped in minute. It is pumping less than half of the stated rate. New pump for me then !.

 

Many thanks to all for their help.

 

Badger

[Alan Saunders]

just back from boat ...as Boilerman suggested, tested volume of water pumped in minute. It is pumping less than half of the stated rate. New pump for me then !.

 

Many thanks to all for their help.

 

Badger

The pump's rated volume is with zero 'head' and short, adequate diameter pipes. 5l/m via several metres of 15mm pipes to a shower 2m above the water tank level and may be adequate and reasonable from an 11l/m pump.

 

My 11l/m Surflow provides better pressure than a house tank in the loft but less than many cold water domestic supplies. Flow rate is adequate, within guidelines for economical shower operation.

 

I doubt that a new pump will solve your problem but for ~£60 you will have a spare pump to install if/when the new one fails.

 

Alan

[Tony Brooks]

The pump's rated volume is with zero 'head' and short, adequate diameter pipes. 5l/m via several metres of 15mm pipes to a shower 2m above the water tank level and may be adequate and reasonable from an 11l/m pump.

 

My 11l/m Surflow provides better pressure than a house tank in the loft but less than many cold water domestic supplies. Flow rate is adequate, within guidelines for economical shower operation.

 

I doubt that a new pump will solve your problem but for ~£60 you will have a spare pump to install if/when the new one fails.

 

Alan

 

 

In the OPs second post he says the pump runs constantly - that means no pressure rise high enough to cut out and that means less flow form the pump than can flow from the shower. Water, being a liquid, is all but incompressible so if the above is correct where does the loss of water volume go to except into the accumulator but even so when that is "full" the pressure will rise to cut out point.

 

Long/thin pipes will cause a loss of pressure at the outlet point but in doing so will cause the pump to cycle.

 

I think.

[Badger]

Are you saying that the pump only producing approx 6 litres at a cold tap is about right ?.

[smileypete]

Depends if/how restrictive the tap is.

 

Surest test is take the pump out, clean the strainer and measure 'open flow' into a bucket at 12V.

 

Most take the easy way out and just put in a new pump (but if taking the old one out for replacement anyway why not double check it really IS the pump ...)

 

cheers, Pete.

~smpt~

Edited September 7, 2015 by smileypete

[Dave Clinton]

We have a Par-Max-3.5 which is 13 litres per minute.

 

It feeds 2 bathrooms, a shower room, and the galley.

 

We also have a Par-Max 2.9 which is 11 litres per minute - this feeds the deck wash and gives a good forceful jet on the hose pipe.

 

couple of questions: what do you use at the other end of the deck wash ? A karcher lance or such like? And do you pick up water from the canal or feed it from fresh water?

I saw this http://www.amazon.co.uk/dp/B00EUW28JUfor £17 , it says it's 0.8mpa which google helpfully translates to 110 psi - so I guess something doesn't add up but it might make a good deckwash

[Alan de Enfield]

 

 

couple of questions: what do you use at the other end of the deck wash ? A karcher lance or such like? And do you pick up water from the canal or feed it from fresh water?

I saw this http://www.amazon.co.uk/dp/B00EUW28JUfor £17 , it says it's 0.8mpa which google helpfully translates to 110 psi - so I guess something doesn't add up but it might make a good deckwash

 

 

We have a 'wash brush' - a hose pipe fed brush. Alternatively we have a 'pistol' which has a varying output (just twist a 'ring') from a shower to a jet.

 

Water is picked-up via a skin fitting from the River and pumped up about 8-10 feet to deck level.

[MtB]

just back from boat ...as Boilerman suggested, tested volume of water pumped in minute. It is pumping less than half of the stated rate. New pump for me then !.

 

Many thanks to all for their help.

 

Badger

 

 

Numpty edit. Comments deleted as I thought this was the other thread on a similar subject!

 

The one where a poster had a Liverpool widebeam, and was focusing on the pick-up pipe from their tank being in the wrong place as the reason for poor flow. Now I can't find the thread! Or is this the same poster?

Edited September 8, 2015 by Mike the Boilerman

[Tony Brooks]

Are you saying that the pump only producing approx 6 litres at a cold tap is about right ?.

 

I am not, I am questioning the logic of Alan's post GIVEN YOUR SYMPTOMS.

 

A 11lpm pump delivering 6 lpm from a tap must cycle unless something has reduced the pumps output volume. You said the pump runs all the time the shower is on so it is not cycling. This means the volume it is delivering is less that what is flowing form the shower. If it did not cycle when you tested the flow rate at the tap then I sand by my original diagnosis - one or more pumping chambers faulty, probably with valves jammed open.

 

I agree with Mike that a restriction on the inlet will give the same symptoms so that needs checking. In fact Alan could be correct if your pump is at the opposite end of the boat to the water tank.

[Badger]

Of course i realise that the pump is not likely to produce exactly 11.3 litres. Running off a measured amount from the galley cold tap, that is only about 14ft from the pump...I would not expect a drop of 50% 0f the rated capacity.

[smileypete]

OK, why not put a new pump straight in and measure the flow from the tap

 

cheers, Pete.

~smpt~

[Tony Brooks]

Of course i realise that the pump is not likely to produce exactly 11.3 litres. Running off a measured amount from the galley cold tap, that is only about 14ft from the pump...I would not expect a drop of 50% 0f the rated capacity.

 

Sorry to keep on but flow from the tap is only one of the symptoms of this problem. The other important on is the degree to which the pump is cycling as you draw water from the tap. Plus a statement about what you have done about inspecting/checking the inlet side of the pump.

 

The choice is assuming no cycling:

 

1. Inspect the inlet side, including "rodding through" the the tank outlet stub in case it is rusted up, and dismantling & cleaning the inlet filter that should be fitted. The try again.

 

2. Fit a new pump and try again. If the new pump exhibits the same symptoms then you will have to do 1 above. If the inlet has no filter/strainer then you need to fit one to the new pump.