Proper Accumulator Tank Pressure

[egarant]

Hi,

I have a Shurflo 4008-101-E65 that shows a shut off at 55 psi and a restart at 40 psi.

I have a Shurflo 182 accumulator tank, that if I am correct, should be set at 40 psi. That seems rather hight to me, I believe it is shipped with 20 psi.

I've had them in the past but never paid attention to the proper psi, I just installed them as they came.

Can anyone clarify this?

Thanks,
Eric

[egarant]

Well I called Shurflo today, hard to find their number, but it's 1-800-834-3218, keep it in your phone.

According to the tech, if you have the 4008 pump, as stated the turn on pressure is not the re-start presure and he didn't know why the manual for the pump doesn't clearly state it.

The turn on pressure for that pump is 38 psi, so the accumulator pressure should be set at 38 psi.

I think someone did come to that same conclusion, but I thought I'd double check.

Cheers,

Mr. E

[Vintage465]

I pumped mine up to 40psig to go with a 55 psig pump/system. And I didn't really think it all that easy to connect the dots in the manual........

[C_Schomer]

The reasons for -2 DP and 0 DP are in my previous post. Setting the pressure at zero or slightly less all depends on how fussy you want to get. Zero will give you the maximum draw down and -2 will allow for slight pressure switch variations and make sure the pump always cycles the way it should. You just have to outsmart your bladder!! Haha!

[ScottG]

Dutch_12078 wrote:

ScottG wrote:
Mr. E, please let us know how this works out for you. I have the same pump and have been considering adding an accumulator to smooth out flow but not sure how it will work with these bypass pumps. (Manufacturer just says "not needed").

The accumulator will work ok with a bypass pump. The manufacturer is correct that it's not needed for the low flow pump cycling that occurs with non-bypass pumps, but it still works well for cutting down on how often the pump runs. I have a 2-gallon accumulator installed with a SHURflo Revolution bypass pump, and we can often make it through the night with typical old folks bathroom visits without the pump running at all.

Good info - thx! What did you set the tank pressure to?

[Gdetrailer]

egarant wrote:


I read the manual, I even quoted the one part of the manual that I had a question on....is the RESTART pressure the same as the Turn on Pressure?

That's all.....

There is no such thing as "restart pressure" in water systems.

You have turn on (IE the "lowest" pressure) and turn off (IE the "highest" pressure).

Pump will only "turn on" when the pressure is less or equal to the turn on pressure.

Pump will "turn off" when the pressure reaches the highest pressure and will not turn back on until the pressure falls to or below the turn on pressure.. The pump will not turn on (or "restart" as you put it) until the pressure is equal to or less than the turn on pressure.

So your pressure tank precharge in order to make the system work correctly SHOULD be set no higher than the TURN ON pressure.

The precharge pressure however can be less than the turn on pressure to a certain extent and still work fine. The well driller that I had in to replace my home well pump and pressure tank yrs ago actually sets the precharge 2 PSI below the turn on pressure.. Not sure exactly why, but it works fine, the guy does that for a living so he must have some reasoning for doing it that way.

To be clear, turn on is the lowest pressure.

Pump will not turn on between the turn off and turn on after it has been tripped to off until pressure drops to or below the turn on pressure..

You do not want the precharge to be higher than the turn on, otherwise, why bother with the pressure tank?

Turn off is the highest pressure.

[Dutch_12078]

ScottG wrote:
Mr. E, please let us know how this works out for you. I have the same pump and have been considering adding an accumulator to smooth out flow but not sure how it will work with these bypass pumps. (Manufacturer just says "not needed").

The accumulator will work ok with a bypass pump. The manufacturer is correct that it's not needed for the low flow pump cycling that occurs with non-bypass pumps, but it still works well for cutting down on how often the pump runs. I have a 2-gallon accumulator installed with a SHURflo Revolution bypass pump, and we can often make it through the night with typical old folks bathroom visits without the pump running at all.

[C_Schomer]

I was taught to run the bladder pressure at two psi below the pump cut in pressure and that always worked great for me. The reason is, so there will be a little bit of leeway so the bladder will still have some cushion affect just before the pump comes on. I always use the same gauge to check the pump cut in pressure and to pressurize the bladder.
Running the bladder pressure exactly the same as the pump cut in pressure would give the max drawdown but I never tried to get that precise … flip a coin. Craig

[ScottG]

Mr. E, please let us know how this works out for you. I have the same pump and have been considering adding an accumulator to smooth out flow but not sure how it will work with these bypass pumps. (Manufacturer just says "not needed").

[egarant]

Thanks so much!

Mr. E

[opnspaces]

Yes turn on pressure and restart pressure and accumulator pressure (aka pre-charge) should all match.

[egarant]

Gdetrailer wrote:

egarant wrote:

shastagary wrote:
ACCUMULATOR TANK: Model 182
INSTALLATION MANUAL

Thanks, but I do have those manuals, I'm interested in what the proper set pressure...

Egads man, don't be so lazy, read the manual!

From the manual that was linked above (took me a whole 2 seconds to find the info)..

"RV/MARINE APPLICATIONS WITH PRESSURE SWITCH-CONTROLLED PUMPS
The accumulator contributes to longer pump life, less noise, less amperage draw, and reduced water pulsation.

The most efficient use of the accumulator occurs with the pre-charge set at the SAME pressure as the pump’s pressure switch “turn
on” setting.

Typically, a 45 psi [3 bar] pump will turn on around 30 psi [2.07 bar]. Therefore, the pre-charge should also be 30 psi [2.07 bar]. The pre-charge MUST be set in a “static” condition (pump off and at least one water fixture opened).

Depending on pre-charge pressure to the accumulator, in relation to the pump turn on/off pressures, stored liquid is about
2 to 4 oz. [60-120 ml]. If accumulator tank pre-charge exceeds pump turn on pressure, the liquid volume is reduced."

Simply put, find the TURN ON pressure of YOUR pump, set accumulator pressure to the TURN ON pressure of YOUR PUMP.

Is that clear enough?

I read the manual, I even quoted the one part of the manual that I had a question on....is the RESTART pressure the same as the Turn on Pressure?

That's all.....

[Gdetrailer]

egarant wrote:

shastagary wrote:
ACCUMULATOR TANK: Model 182
INSTALLATION MANUAL

Thanks, but I do have those manuals, I'm interested in what the proper set pressure...

Egads man, don't be so lazy, read the manual!

From the manual that was linked above (took me a whole 2 seconds to find the info)..

"RV/MARINE APPLICATIONS WITH PRESSURE SWITCH-CONTROLLED PUMPS
The accumulator contributes to longer pump life, less noise, less amperage draw, and reduced water pulsation.

The most efficient use of the accumulator occurs with the pre-charge set at the SAME pressure as the pump’s pressure switch “turn
on” setting.

Typically, a 45 psi [3 bar] pump will turn on around 30 psi [2.07 bar]. Therefore, the pre-charge should also be 30 psi [2.07 bar]. The pre-charge MUST be set in a “static” condition (pump off and at least one water fixture opened).

Depending on pre-charge pressure to the accumulator, in relation to the pump turn on/off pressures, stored liquid is about
2 to 4 oz. [60-120 ml]. If accumulator tank pre-charge exceeds pump turn on pressure, the liquid volume is reduced."

Simply put, find the TURN ON pressure of YOUR pump, set accumulator pressure to the TURN ON pressure of YOUR PUMP.

Is that clear enough?

[egarant]

shastagary wrote:
ACCUMULATOR TANK: Model 182
INSTALLATION MANUAL

Thanks, but I do have those manuals, I'm interested in what the proper set pressure...

[shastagary]

ACCUMULATOR TANK: Model 182
INSTALLATION MANUAL