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22-10-2015, 17:13
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#1
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Registered User
Join Date: Aug 2008
Location: Hawaii
Boat: CS 40
Posts: 171
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Accumulator or Pump Switch
Quite suddenly in the last day or so our fresh water pump cycles on as soon as we open a faucet. I pumped air into the accumulator with a bicycle pump which made no difference. I then disassembled the pump head (Shurflo 2088 series) and cleaned then reassembled. No difference.
I'm at a loss as to why we suddenly have no accumulator effect.
Also when the pump runs, it seems to stutter as though it's cycling very quickly.
I'm at a bit of a loss.
__________________
Michael Fössl
S/V Second Jump
British Columbia
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22-10-2015, 18:42
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#3
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Registered User
Join Date: Jan 2008
Location: Kingston, ON
Boat: Albin Vega 27'
Posts: 530
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Re: Accumulator or Pump Switch
Might want to look at the check valve (pressure holding), had a similar problem with my well pump at home recently.
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Glenn
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22-10-2015, 23:06
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#4
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Senior Cruiser
Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 3,499
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Re: Accumulator or Pump Switch
Agree with sailorchick34... sounds like your accumulator no longer has a working diaphragm. Some can be opened. I doubt a new diaphragm can be found. Older accumulator tanks, 20-30 years ago, had no diaphragm and depended on an air bubble to compress. Over time the tank would loose the air bubble, completely fill with water and you get the short cycling. You could try completely draining your accumulator as a temporary fix.
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23-10-2015, 07:33
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#5
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Registered User
Join Date: May 2011
Location: Miami Florida
Boat: Ellis Flybridge 28
Posts: 4,057
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Re: Accumulator or Pump Switch
What Sailor Chick said. Replace the accumulator tank.
__________________
Retired from Hopkins-Carter Marine Supplies
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23-10-2015, 08:41
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#6
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Registered User
Join Date: Aug 2008
Location: Hawaii
Boat: CS 40
Posts: 171
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Re: Accumulator or Pump Switch
Our accumulator is vertically oriented with a bike tube valve on top. In the past when the pump started to short cycle I pumped air into the accumulator with a bicycle pump which solved the problem. Now it makes no difference.
I assume that even with a leaking diaphragm, the air pumped into the tank would resolve the short cycling at least for a while.
I did another test where after I pumped air into the accumulator I turned on the pump and after it turned off, I released some air from the valve in the accumulator. The pump cycled on. It seems that the accumulator is operating.
This leads me back to the pump switch. Is it just the inherent design of the switch to have a high and low pressure differential? There is only one screw to adjust the overall pressure of the pump.
__________________
Michael Fössl
S/V Second Jump
British Columbia
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23-10-2015, 09:28
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#7
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Registered User
Join Date: Feb 2007
Location: Live in Boise, boat is in the Rio Dulce
Boat: 56' CNSO Mikado Cutter Ketch
Posts: 367
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Re: Accumulator or Pump Switch
Very simple to determine if the accumulator tank is functioning properly with a tire gauge. Pump it up, check the psi every few minutes. Should be obvious within a short period of time if the tank is leaking or not.
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23-10-2015, 09:38
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#8
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Moderator Emeritus
Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 5,486
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Re: Accumulator or Pump Switch
Quote:
Originally Posted by mikefossl
Our accumulator is vertically oriented with a bike tube valve on top. In the past when the pump started to short cycle I pumped air into the accumulator with a bicycle pump which solved the problem. Now it makes no difference.
I assume that even with a leaking diaphragm, the air pumped into the tank would resolve the short cycling at least for a while.
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When you pumped air in, was the pump off and a faucet open. there has to be a place for the water that is not compressable under normal pressures, to go when it's displaced by air.
A tank with a torn bladder can operate for a few days. So try it after filling the accumulator with air again. If the pump cycles on and off after that as it should then it's the accumulator. If the pump short cycles then it could be bad contacts (arc'ed/ pitted)on the pressure switch.
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24-10-2015, 07:46
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#9
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Registered User
Join Date: Mar 2003
Location: Currently on the boat, somewhere on the ocean, living the dream
Boat: Morgan 461 S/Y Flying Pig
Posts: 2,298
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Re: Accumulator or Pump Switch
Quote:
Originally Posted by sailorchic34
When you pumped air in, was the pump off and a faucet open. there has to be a place for the water that is not compressable under normal pressures, to go when it's displaced by air.
A tank with a torn bladder can operate for a few days. So try it after filling the accumulator with air again. If the pump cycles on and off after that as it should then it's the accumulator. If the pump short cycles then it could be bad contacts (arc'ed/ pitted)on the pressure switch.
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What she said. Beat me to it.
Relieve any pressure in the line before you pump. It will still be challenging to pump as you have to remove the water in the line with the air you're pumping, if the diaphragm is intact. If it's not, still displace all the water. When you're pumping air through the faucet, you're as far as you can go if the diaphragm is toast.
If you do that AND still have the immediate cycle, it's your switch or one-way valve. Otherwise it's the accumulator. I took out our pringles can version for a big-box several-gallon unit; that lasted 8 years and I just replaced it. I'm not at the boat so don't have pix for you but this will give you an idea:
Pictures: Flying Pig Shakedown 2013-2014/New Accumulator Tank
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24-10-2015, 09:02
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#10
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Registered User
Join Date: May 2011
Location: Miami Florida
Boat: Ellis Flybridge 28
Posts: 4,057
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Re: Accumulator or Pump Switch
Newer pumps don't need accumulator tanks. Jabsco makes pumps with variable speed motors that just deliver as much water as needed. Shurflo makes pumps with a bypass that feeds excess water back to the inlet. Neither type needs an accumulator tank to prevent short cycling. Next time you need a new pump you might want to try one of these and free up the space the tank now occupies.
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Retired from Hopkins-Carter Marine Supplies
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24-10-2015, 09:17
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#11
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Registered User
Join Date: Feb 2007
Location: St Thomas USVI
Boat: Freedom Express 39 cat ketch
Posts: 752
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Re: Accumulator or Pump Switch
How's the reliability of the newer Jabsco and Shurflo pumps? I believe I read about a variable speed Jabsco, don't recall model number, but it didn't get very good reviews for noise or longevity.
Sent from my iPhone using Cruisers Sailing Forum
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24-10-2015, 13:44
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#12
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Registered User
Join Date: May 2011
Location: Miami Florida
Boat: Ellis Flybridge 28
Posts: 4,057
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Re: Accumulator or Pump Switch
Both Jabsco and ShurFlo came out with variable speed pumps about ten years ago. Both had problems. ShurFlo gave up on the variable speed idea and went with the simpler mechanical bypass. Jabsco stuck with the electronically controlled variable speed.
Both are much improved over their earlier efforts.
The ShurFlo turns on and runs full speed as long as there is a demand for water.
The Jabsco turns on when ever you open a faucet but only runs fast enough to deliver the required amount of water. It's quieter than the ShurFlo, most of the time.
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Retired from Hopkins-Carter Marine Supplies
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29-10-2015, 06:41
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#13
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Registered User
Join Date: Aug 2009
Location: Saint Petersburg, Florida
Boat: CSY 33
Posts: 179
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Re: Accumulator or Pump Switch
I agree with HopCar. I have a newer Jabsco that doesn't require an accumulator pump. It is noisy but I mounted it with foam under the mounting feet and it helped reduce the noise. I like to hear it come on. I found a small leak after hearing the pump start up and shut off a few times.
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