To accumulate or not?

[Tom]

Accumulators in your fresh water system are intended to reduce the frequency with which your water pump(s) turn on. So, for example, if you go to the bathroom in the middle of the night, turning on a faucet shouldn't cause the water pump(s) to turn on and wake up the other half. However, there are different sizes of accumulator tanks and some water pumps don't work well with accumulators, specifically the variable speed pumps.

What has been your experience with accumulators & different pumps? What's the optimum size accumulator tank?

 

[Rex]

Tom, I installed a 2-gal unit in a previous coach.  Worked like a charm, and never had a problem with it.  I used one like you would find in a home installed above the hot water tank.  Reduced the inlet fitting down to connect to the coach water line. 

Also installed a cutoff valve for winterizing it.  I would drain the system, and close the valve BEFORE putting pink stuff in the water system.  No need to fill a 2-gal tank.  The tank was pressurized to 22-PSI so all water would be expelled when the system was drained.

Don't have one in my current Monaco, but am planning on installing one.

 

[Tom]

Thanks Rex. We have one on the boat, but not the coach. I saw some discussion on a Monaco group about someone wanting to install a 10 gallon accumulator tank, but I'm not sure I follow the logic.

I used one like you would find in a home installed above the hot water tank.

Haven't seen one above the (home) hot water tank since I lived in the UK. Where did you buy the "above" tank?

We don't winterize the coach; The few nights that it gets below freezing here I move the coach from the storage lot to the house and turn on the basement heater and turn the furnace on low.

 

[Alaskansnowbirds]

I saw some discussion on a Monaco group about someone wanting to install a 10 gallon accumulator tank, but I'm not sure I follow the logic.

The larger the tank the longer between the times the pump runs.

 

[Tom]

Understood Don. But 10 gallons to wash my hands in the middle of the night  ???

 

[Gary RV_Wizard]

A well installed pump makaes little or no noise, so maybe it makes more sense to modify a noisy pump than to add an accumulator.  And its my undertstanding that the variable pumps are really quiet when the demand is small, e.g. washing your hands.

 

[King]

An accumulator tank doesn't fill with water.  If it did, it wouldnt work.  Water isn't compressible.  The air in the tank is compressed to the maximum pump pressure when the pump is on.  it will then provide pressure for water flow until the pressure drops far enough for the pump to turn on again.

 

[Karl]

Actually, the tank does partially fill with water. There is a membrane inside which contains the air 'head' under pressure so it is not absorbed over time into the water. It is the air head which helps maintain a more or less constant flow pressure until the 'draw down' point (how many gallons of water you can extract) is reached, and the pump is again turned on to replenish the water and working pressure in the tank. In some newer homes with well water, there is no accumulator, and the pump runs continuously. The advantage is constant pressure at all times, but the downside is continuous energy usage - not practical for RV's IMHO. 

 

[Ron]

With the Aqua Jet variable speed pump like what is being installed in many Motorhomes a accumulator is not necessary.  We have the AquaJet pump and it has been great.

 

[Tom]

A well installed pump makaes little or no noise, so maybe it makes more sense to modify a noisy pump..

That's what I'd have thought. But apparently folks are having all kinds of noise and other problems with new pumps.

 

[Tom]

Some folks have reported problems with variable speed pumps, specifically the power draw, and have replaced them with a fixed speed pump and accumulator.

 

[Ned]

We replaced our original Shurflo with an Aquajet ES pump and it's no quieter than the Shurflo. ?It still pulsates, especially at low flow rates. ?I don't think I'd spend the money on another one when this one fails. ?I might try one of the Shurflo models, they seem to be getting some good reviews in other forums.  I'd add an accumulator at that time if I can find one that will fit.

 

[Gary RV_Wizard]

Ned,
Strange that a variable speed pump would pulse - that's the antithesis of what it is supposed to to do. Maybe its  more like steps than continuously variable?  Have you inquired at Aquajet about it's poor performance?

Tom,
I'm curious - where did you hear that power draw is a problem? I know that at full flow they draw quite a bit, but supposedly they don't often run at full flow (but I guess a shower would do that).  The bigger models, e.g. the 5.7 gpm would certainly draw some power, but so would a larger fixed flow pump. I think standard RV pumps are well under 5.7 gpm, but don't have thedata handy.  I'm getting low speed on the cell phone here in the boonies northwest of Cortez, so can't search around the net for pump specs right now.

 

[Ned]

At low flow rates, it does pulse.  At higher rates, it's not as noticeable.  In any case, I don't see that it was worth the cost.  I could buy several standard pumps for the cost of this one.

 

[Tom]

...where did you hear that power draw is a problem?

It was on a private group. I need to go back and research all that was said.

 

[Ron]

On the other hand we think the AquaJet is the best pump available.  We sure appreciate ours and wouldn't even consider another shurflo or flojet both of which I consider inadequate pieces of J---K.

 

[Karl]

Gary,

Interestingly, the AquaJet has a Pulsation Dampener available. http://www.rvupgradestore.com/browseproducts/Aquajet-Pulsation-Dampener.html

From their descriptions for both the 3.5 & 5 gpm: "PUMP DESIGN: 5 Chamber Diaphragm Pump, Self Priming,Capable of Being....", the 3.5 draws max. 6.5 amps while the 5 draws max 10 amps. Also a caution of 150F temerature of the motor after 5 minutes of full capacity running.

 

[Ron]

Maybe that is the difference.  I received a dampening hose when I bought the pump.  Install instructions advise to install with a looped hose on the outlet.

 

[Shayne]

Shucks guys --I'm just happy to have water.  That noise don't bother me. It just tells me it's working.  Of course like in the Q you have to turn the valve on.  I'll never live that one down.

 

[Rex]

Tom, we lived in the Knoxville, Tennessee area for several years.  There they put the accumulator tank just above the hot water heater.

The one I installed in my previous coach came from  a hardware store that was going out of business.  Was priced just too low to leave it there.  I have seen the same tank at Lowe's for about $40.