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Date: 02 Jul 2007 11:31:19
From: Nick Alexander
Subject: Does a rotary pump need a high-pressure inlet?
I have just bought a machine with a rotary pump. Our house is on a
gravity feed water system, with the tank about one floor above the
machine, so very low pressure. Can I feed this straight into the
rotary pump? someone recommended that I fit a non-return valve on
the inlet of the pump to prolong it's life.

What do people think?





 
Date: 03 Jul 2007 10:50:13
From: DavidMLewis
Subject: Re: Does a rotary pump need a high-pressure inlet?
You do want a check valve, as well as an inlet filter if the machine
doesn't have one (most do). With such low feed pressure, you should
make sure you have enough flow. When doing auto-fill, the machines
I've seen will draw about 250 ml in ten seconds. If the inlet doesn't
flow that much, the pump will cavitate, which you don't want. If that
turns out to be a problem, you'll need some sort of storage local to
the machine.

Best,
David



 
Date: 03 Jul 2007 11:27:20
From: daveb
Subject: Re: Does a rotary pump need a high-pressure inlet?
it should do fine.
the main thing is your water source is above the pump.


dave
www.hitechespresso.com


"Nick Alexander" <nic.alexander@gmail.com > wrote in message
news:1183375879.121918.289040@i13g2000prf.googlegroups.com...
>I have just bought a machine with a rotary pump. Our house is on a
> gravity feed water system, with the tank about one floor above the
> machine, so very low pressure. Can I feed this straight into the
> rotary pump? someone recommended that I fit a non-return valve on
> the inlet of the pump to prolong it's life.
>
> What do people think?
>




  
Date: 03 Jul 2007 18:05:36
From: Dan Bollinger
Subject: Re: Does a rotary pump need a high-pressure inlet?
Dave, Maybe not. I checked at Procon, the little Series 1 pump is self-priming
up to 6 ft. suction lift. Meaning it can draw water from a tank 6 ft. below the
pump and still operate normally. Dan


> it should do fine.
> the main thing is your water source is above the pump.
>
>
> dave
> www.hitechespresso.com
>
>
> "Nick Alexander" <nic.alexander@gmail.com> wrote in message
> news:1183375879.121918.289040@i13g2000prf.googlegroups.com...
>>I have just bought a machine with a rotary pump. Our house is on a
>> gravity feed water system, with the tank about one floor above the
>> machine, so very low pressure. Can I feed this straight into the
>> rotary pump? someone recommended that I fit a non-return valve on
>> the inlet of the pump to prolong it's life.
>>
>> What do people think?
>>
>
>



   
Date: 05 Jul 2007 09:14:03
From: daveb
Subject: Re: Does a rotary pump need a high-pressure inlet?
just being conservative

: )

d
"Dan Bollinger" <danNObollinger@insightSPAMbb.com > wrote in message
news:-uidnW9jK5DTVRfbnZ2dnUVZ_jqdnZ2d@insightbb.com...
> Dave, Maybe not. I checked at Procon, the little Series 1 pump is
> self-priming up to 6 ft. suction lift. Meaning it can draw water from a
> tank 6 ft. below the pump and still operate normally. Dan
>
>
>> it should do fine.
>> the main thing is your water source is above the pump.
>>
>>
>> dave
>> www.hitechespresso.com
>>
>>
>> "Nick Alexander" <nic.alexander@gmail.com> wrote in message
>> news:1183375879.121918.289040@i13g2000prf.googlegroups.com...
>>>I have just bought a machine with a rotary pump. Our house is on a
>>> gravity feed water system, with the tank about one floor above the
>>> machine, so very low pressure. Can I feed this straight into the
>>> rotary pump? someone recommended that I fit a non-return valve on
>>> the inlet of the pump to prolong it's life.
>>>
>>> What do people think?
>>>
>>
>>
>




 
Date: 02 Jul 2007 09:36:22
From: Dan Bollinger
Subject: Re: Does a rotary pump need a high-pressure inlet?
Mine is feed by only 15 psi. Your pressure would be about 4-5 psi. Rotary pumps
are displacement pumps and should be able to operate at slight negative inlet
head. That is, they should be able to draw water up from a tank under a counter,
or even the next floor down.

To be sure you don't get cavitation, see the pump specs. If Procon:
http://www.proconpumps.com/

Dan

>I have just bought a machine with a rotary pump. Our house is on a
> gravity feed water system, with the tank about one floor above the
> machine, so very low pressure. Can I feed this straight into the
> rotary pump? someone recommended that I fit a non-return valve on
> the inlet of the pump to prolong it's life.
>
> What do people think?
>