Constant pressure or accumulator type pumps

**Bung** · 20-11-2011, 12:49 PM

Some info on accumulators:

ACCUMULATOR TANK: Model 182
INSTALLATION MANUAL

The SHURflo Accumulator tank is a bladder type pressure storage vessel and/or pulsation-dampening device designed to
hold water under pressure. The accumulator tank provides additional water storage to assist the pump in meeting the total
demands of the system. It extends pressure switch-controlled pump life by reducing pump on-off pulsation.
NOTE: This product is not recommended for use with a 4900 or 5900 Series Smart Sensor Pump.
• See Product label and Specifications section on page 2 for factory pre-charge pressure. Do not exceed
40 psi [2.7 bar] pressure for long-term storage, shipping, or during system non-use.
• It is recommended the pre-charge be checked seasonally, or any time the accumulator does not appear to be
functioning properly. Temperature extremes and changes in altitude can affect accumulator pressure and
performance. Use a standard tire pressure gauge to check the pressure. The valve stem cap MUST be tight to
prevent air leakage.
• The accumulator may be placed anywhere in the pressurized side of the plumbing. It should be installed after the
pump and before any filters or check valves that can add backpressure to the pump or system. The ports are non-
directional in flow and do not have to be plumbed in line (one side can be capped).
• The accumulator can be mounted in any position. However, for complete sanitizing/winterizing, the recommended
mounting position is with pre-charge valve stem up. Do not freeze or mount near a high heat source.
• Threaded fittings (plastic/nylon only) should be torqued approximately 1/2 to 1 turn after hand-tightened. Never
exceed 6 ft/lbs [88 Nm] of torque on the ports. Plumb the system using high pressure (2x pump rating), braided,
flexible tubing to minimize vibration/noise.

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.

WATER HAMMER APPLICATIONS
When used as a dampening device/water hammer or noise suppressor, the pre-charge should be set at the operating
(dynamic) pressure. Place a gauge in the offending plumbing where the accumulator can be mounted. Adjust the valve so
the noise is generated and read the pressure. Set the pre-charge to the observed pressure, remove the gauge, and install
the accumulator. Refer to SHURflo Service Bulletin #1024 for more application information.

TROUBLESHOOTING

SYMPTOMS POSSIBLE SOLUTIONS

Does not function; pump cycles rapidly Check air pressure. Add or remove air as necessary.

Water leaks from valve Diaphragm is torn or has a hole. Replace accumulator.

Does not hold air pressure Screws loose, air valve, torn/hole in diaphragm. Replace accumulator.

Leaks from fittings or ports Check fitting connection. Ports must seal on internal port taper,
Ports should not be sealed on threads with NPT fittings
TESTING AIR PRESSURE
Check air pressure with pump off and one or more faucets open [no water pressure in the system]. Adjust pressure as
needed. If unit leaks water from air valve or does not hold pressure, unit must be replaced.

NOTE: There are no replacement parts or kits for this accumulator. If it is not working, it must be removed or
replaced.

**Bung** · 20-11-2011, 01:10 PM

This is the best explanation:

Accumulator tanks use air to store energy to maintain system pressure between pumping cycles. In most modern accumulator tanks, the air is contained in a flexible bag, instead of just being exposed to the water. This allows you to use more air without losing it every time you run out of water. It also allows for the possibility storing too much air in the tank. To get the most benefit from a given size tank, you should maximize the amount of usable air in the tank. If you put too much air in the tank, it becomes unusable when it finishes pushing all the water out of the tank. You have the maximum amount of usable air when the tank is almost empty (of water) when the pressure switch turns the pump on.

Here’s how you can achieve the ideal amount of air charge: First, determine what the system pressure is when the pressure switch turns on the pump. Do this by draining water very slowly, while listening for the pump start-up. Turn off the pump the moment you hear it start up. At this point you can read the system pressure using an ordinary automotive tire pressure gage on the air fill fitting. This is the pump cut-in pressure. Next, drain all the water out of the system and measure the air pressure again. This is the air-charge pressure. The air charge pressure should be just a little less than the pump cut-in pressure.

If you find that both pressure readings are the same, then you are far over-charged with air. Don’t be surprised, many new accumulators come charged with 50 psi of air. Very few boats run that high of water pressure. With that much pressure, the incoming water never compresses the air, so no water is stored in the tank. Bleed the pressure down some, but try not to let all the gas out. Some new tanks come charged with nitrogen instead of air, which is a little better for the rubber air sack than air. Try bleeding the pressure down to 25 psi and then check the pressures again. Continue bleeding 5 psi at a time until the empty tank air pressure a little less than the pump cut-in pressure.

**ralphlsasser** · 22-11-2011, 05:24 AM

Thanks Bung. Mine looks similiar to the first picture except my tank is on top. If that matters.

**Marmite the Dog** · 15-12-2011, 10:32 PM

I just got a 200w Hitachi pump like this one. The EX has the metal cover and is on special at the moment while the GX(?) is the new model with a plastic cover that will eventually crack according to the plumbing expert at Tool Pro (yes, he did actually know what he was doing unlike the first idiot who 'looked after' us).

We had a small problem that the spring on the return valve was too strong and the pressure from the water tank couldn't open it (even though the tank is 2m high and the water comes through a 3/4" pipe.

I simply removed the unnecessary spring and it works a treat. You can have a shower, flush the loo and open a couple of taps and it doesn't miss a beat.

**DrAndy** · 16-12-2011, 07:07 AM

Originally Posted by Marmite the Dog

The EX has the metal cover and is on special at the moment while the GX(?) is the new model with a plastic cover that will eventually crack according to the plumbing expert at Tool Pro

I have the GX and no signs of cracking!! wonder what I have to do to make it crack?

**Marmite the Dog** · 16-12-2011, 07:40 AM

Originally Posted by DrAndy

wonder what I have to do to make it crack?

Place it in direct sun light? Drop something on it? Get a Thai to install it?

I'm sure he tell those who buy the GX that it's better because it doesn't rust.

**DrAndy** · 16-12-2011, 07:49 AM

yes, it doesn't have any rust at all

actually, it is a good pump. I have had it for two years now and the only problem was that ants got into the pressure switch and stopped it working. They seemed to think that it was a good place to build a nest; I proved them wrong with some harsh chemicals.

They pissed all over the switch contacts which stopped it working properly even after they had been cleared out, but a bit of emery cloth slid between the contacts soon fixed that

besides the cover, I think the EX and GX are a bit different, see Bungs post #25

**Bung** · 16-12-2011, 10:21 AM

I finished up my installation the other day, ended up diong it all myself so I couldn't complain about a shite job...

Bought a GX 250 pump, may have been overkill but it was on special for only 400B more than a 200. everything seems fine, although when taking a shower or running a sprinkler on it's own it will cycle slowly which I am not sure if it is better for it to just run constantly or switch on and off slowly.....I may have to fiddle with the pressure switch.

Incedentally these have no air fitting to pressurise the accumulator so all my cut and pasting is worthless for these pumps. If the start to short cycle you just need to drain the tank out and run it up again.

Marmite, I was told to remove that spring by the guy in the shop, he said that is for if it is sucking from a well but mine is in still and runs fine....I may pop it out to check the difference.

Here is my installation:

You can see the bypass just to the right of the pump, I run it on moo baan pressure most of the day, just swing it over in the evenings for watering and showers. real easy. I also run the cables under ground and mounted a switch on the corner of the house so you just switch it on or off there without bending over and rummaging through the (soon to come) garden. I also used these compression fittings, they are great as you can disconnect them and remove the pump and tank later without cutting although I couldn't get them to work on the outlet-too much pressure and blew apart so I had to glue that up. They did have nice stainless fittings and couplings but there was little stock right now and not the size I needed. (1").

The tank, I was going to get a stainless one but liked this as it was lower, had the supply line internal, was cheaper and looked nicer. It has a valve at the very bottom to flush it (I have a nipple in it so can connect a hose and run it away) and with the couplings it is pretty easy to move it away all together.

Pretty happy with it all.

**Bung** · 16-12-2011, 12:21 PM

Originally Posted by Marmite the Dog

We had a small problem that the spring on the return valve was too strong and the pressure from the water tank couldn't open it (even though the tank is 2m high and the water comes through a 3/4" pipe.

From the manual:

"In case the suction range is less than 3m or the water pump is higher than the pump head (not exceeding 2m) put the check spring in the check valve."

make of that what you will

Just took mine out - same. Will check it over a day and leave it out if ok, after all, the "expert" I bought it off said to take it out.....

**Maxion** · 16-12-2011, 02:46 PM

Originally Posted by Bung

I also used these compression fittings, they are great as you can disconnect them and remove the pump and tank later without cutting although I couldn't get them to work on the outlet-too much pressure and blew apart so I had to glue that up. They did have nice stainless fittings and couplings but there was little stock right now and not the size I needed. (1").

Plastic unions are the answer

**Marmite the Dog** · 16-12-2011, 03:07 PM

Originally Posted by Bung

From the manual:

I didn't get a manual, as I bought a display model cheap.

**Bung** · 16-12-2011, 03:37 PM

Originally Posted by Maxion

Originally Posted by Bung

I also used these compression fittings, they are great as you can disconnect them and remove the pump and tank later without cutting although I couldn't get them to work on the outlet-too much pressure and blew apart so I had to glue that up. They did have nice stainless fittings and couplings but there was little stock right now and not the size I needed. (1").

Plastic unions are the answer

Bollocks! Didn't see any of them!

**Bung** · 17-12-2011, 10:26 PM

I think I will put the spring back in, I can't tell any difference except I can hear the check valve slam shut clearly when the pump stops which I couldn't with the spring in. It has a rubber seal so it may save on wear and is quieter anyway.

Thread: Constant pressure or accumulator type pumps

Thread Tools

Display

Thread Information

Users Browsing this Thread

Posting Permissions