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Accumulator tank - replace or not?
In late 2009, the LD group was hot with talk about the Shurflo Extreme pump problems.  I did some research and found pressures as high as 150 psi, when I started the water heater in the morning.  At those pressures, my fittings and the pump would spring leaks.  I ordered a new pump, and an accumulator tank.

My log notes:

October 29, 2009
The water pump is here. I am not going to install it – yet. I hope to solve the
leaking with an accumulator tank. I have one ordered.
ShurFlo advised against the use of an accumulator tank but the issue seems clear
to me. I have installed a pressure gauge that shows that, when I turn on the heater the
system pressure increases to 150, at which time leaks occur - somewhere. The air space
in the heater is not sufficient to address the water expansion. From an engineering
perspective I see no difference to the pump from an air space in the heater and an air
space in the heater and the accumulator tank, except that the space in the heater is
insufficient to accommodate the expansion.

November 5, 2009
I am in Newport, Oregon. …The water system continues to stay dry if I keep the water pressure below 150. I
have an accumulator tank on order.

November 11, 2009
I got Enterprise her 15,000 mile service today. All. OK.
Additionally, the accumulator tank arrived and I installed it. So far, it seems to be
working as hoped. Tomorrow morning when I heat water will be the real test.

With the accumulator tank in place, I had no more leaks, and my pressure stayed below 105.  The pump eventually failed, and I replaced it with a Revolution.  Since then, no problems.  In the past few days, however, I noticed that my pump is cycling more often than it used to, and with the pump off, an open faucet drops pressure to zero more quickly than normal.  This could be due to two causes.  Either the water heater air space needs to be restored, or the accumulator has lost its air cushion, or both. 

Yesterday, I turned off the pump and opened a faucet, then opened the water heater pressure relief valve to restore the air cushion there.  Not much water came out, suggesting that the air cushion was up to spec.  I took the cap off the Schrader valve on the accumulator tank to check its pressure.  It should have been 30 psi.  What I got was… water.  Clearly, the diaphragm had failed.

SO - I removed the accumulator tank.  I am now debating with myself whether I should replace it.  The points favoring replacement include less pump cycling and more stable flow and pressure.  The points against replacement include fewer components means fewer possible leak points, plus I have more space in that tight compartment by the water pump.  Reading accumulator tank reviews on Amazon, the positives predominate, but the negatives all talk about leaking - leaking fittings on the tank and leaking at the seam where the two halves of the tank are joined together on the diaphragm.

Any thoughts or input on whether to replace the accumulator tank would be welcome.

Ken F in NM
'08 MB
Re: Accumulator tank - replace or not?
Reply #1 –
   Ken. Years ago (about 23 years) I made my own accumulator for my SOB out of a !-1/2" vertical piece of PVC. No diaphragm, but a flexible 'polyflow' hose back down to the refrigerator access hatch. It would have been winterized if needed. Like the water heater the air cushion could be renewed by draining the water, and opening the valve on the airline coming down to the hatch. It is still working today for the person I sold it to. (a coworker) If you already have the plumbing in place, and you can get a new accumulator the same size, I would just replace it. I do a 'dump and fill' about every two months on my water tank/heater depending on how much I use the motorhome. The water goes into my rain barrels. I want fresh water in the MH when, as Larry says, 'The big one hits'. I live about 7 miles from the Rose Canyon earthquake fault. I notice that to replenish the air cushion in my water heater completely I need to open the overpressure valve at the top.
   On a related note I once awoke to a water geyser in my front yard. The top of a sprinkler vacuum breaker had blown off. Investigating that I found my unregulated inlet water from the city at about 300 PSI (gauge only went to 250). About then the city arrived to fix the in-street pressure regulator that had failed. Good thing the regulator on my house did its job.
   Have you thought about an overpressure valve set to something in the 60-80 psi. range?  HTHelps  RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Accumulator tank - replace or not?
Reply #2 –

It's rather amusing that SHURflo recommended against an accumulator tank, since they sell several such tanks under their own brand name.

I'm in the process of reworking my 2003 midbath's plumbing, including installing an accumulator tank. My current setup--more or less a feasibility test--features a half-gallon Whale accumulator tank and matching pump. I intend to replace that tank with a two-gallon tank in the near future.

My aim is not just to relieve strain on the system due to water heater overpressure. I want to eliminate the noise of the water pump every time I turn on a faucet, and the surging behavior of the SHURflo 4008 pump when I'm running just a trickle, as I often do. That means leaving the water pump switched off normally and relying on the accumulator tank to deliver the water I need most of the time, only turning on the pump briefly to refill the tank. To facilitate this, I've made a couple of simple electrical changes.

First, I installed a momentary (only on while held down) toggle switch in the bathroom. I mounted it on the slanted front panel below the sink, where it's out of the way yet easily accessible. (Why momentary? So I won't forget and leave the pump on.) I connected it between the water pump’s + 12 V input line and ground--in other words, it's in parallel with the factory-installed water pump switch, so either one can turn on the pump. This lets me leave the pump off, but turn it on when needed--that is, when the accumulator tank runs out of oomph.

Next I replaced the factory-installed water pump switch on the stove hood with a momentary switch that only powers the pump while held down. The swap was easy, since it's a direct replacement for the original switch; just pull off the quick-connect wires on the back, snap out the old switch, and pop in the new one.

So how does it work in practice? Very well. The water pump is un-powered 99% of the time. (That's a good way to avoid plumbing disasters, by the way.) When I open a tap or flush the toilet, water flows steadily and quietly. A few times a day I'll hold down one of the switches for twenty seconds or so to replenish the pressure in the accumulator tank.

The only shortcoming I've found is that the half-gallon accumulator tank doesn't last quite as long as I'd like... hence my plan to swap in a two-gallon tank. With the new tank, I should be able to go all day without hearing the pump run. That seems like a small thing, but you'd be surprised how much it improves my quality of life.

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Accumulator tank - replace or not?
Reply #3 –
Hmm, now where would I be able to fit a 2 gallon tank...  You have me thinking!

Ken F in NM
'08 MB
Re: Accumulator tank - replace or not?
Reply #4 –
"where would I be able to fit a 2 gallon tank?"

I plan to mount mine upside down, on the underside of the shelf above the water pump. (Of course I'll make sure there's enough structural strength to bear the tank's roughly 20-pound filled weight.)
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Accumulator tank - replace or not?
Reply #5 –
Quote from: Andy Baird  - 
I plan to mount mine upside down, on the underside of the shelf above the water pump.

Hello Andy.  When you complete this project, would you post pictures of the results?  This idea for a 2 gallon accumulator tank is very interesting for just the reasons you mentioned in your post.

P.S.  Found this video that shows the installation of a 2 gallon accumulator tank.  Interesting for sure.

https://www.youtube.com/watch?v=DQYYvxDb10w


Re: Accumulator tank - replace or not?
Reply #6 –
Quote from: Andy Baird  - 
The water pump is un-powered 99% of the time. (That's a good way to avoid plumbing disasters, by the way.)

However, with the 2-gal tank installed, a leak would still create quite a mess until the pressure dropped - and silently. When in our tankless rig, an occasional cycling prompts me to immediately check for a problem. And when I turn the pump off, residual pressure would drop fast if there is a leak. Another tried-and-true method to avoid pressure build is to turn off the pump and open a faucet while the water heater warms. You can catch the small amount of water that drips into a pan to recycle.

Steve
2004 FL
2013 Honda Fit
Re: Accumulator tank - replace or not?
Reply #7 –
"However, with the 2-gal tank installed, a leak would still create quite a mess until the pressure dropped - and silently."

Good point, Steve. On the one hand, it would be better than having fifty gallons pumped out of your freshwater tank while you were out hiking... but on the other hand, if it happened in the middle of the night, you'd have no warning, because the pump wouldn't cycle. So I guess I can't claim it's safer this way. But it certainly is more pleasant. :-)
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Accumulator tank - replace or not?
Reply #8 –
To add to all of the thought in this chain,  my '88 MB had a cold side check valve on the water heater.  I believe that it was to keep hot water from flowing to the Swamp Cooler.  I removed the cold side check valve a few months ago because it was leaking on to the floor and I wanted a Winterizing bypass. 
If I replace the swamp cooler will I need to put the cold side check valve back?
Is an accumulator needed with the cold side check valve?
Is an accumulator needed when the Hot water heater is bypassed?

Rod
'88MB
Rodney
1988 Mid Bath
Re: Accumulator tank - replace or not?
Reply #9 –
I don't use an accumulator but I do leave the water pump on all the time when in the RV. A water detector placed next to the water pump did save me once when it alarmed one evening. A leak had developed in a pump fitting.

I would give a link for the water detector but I can't find it on line. There are several others. It uses a 9 volt battery with a low battery alarm which has surprised me a time or two. There would be no way to stop a two gallon accumulator leak even if you were notified. We did seal the wood around the water pump with spar varnish. It will get wet so you may as well be prepared.
Harry 2006RB
Harry 2006RB
Re: Accumulator tank - replace or not?
Reply #10 –
Quote from: hbn7hj  - 
I don't use an accumulator but I do leave the water pump on all the time when in the RV. A water detector placed next to the water pump did save me once when it alarmed one evening. A leak had developed in a pump fitting.

I would give a link for the water detector but I can't find it on line. There are several others. It uses a 9 volt battery with a low battery alarm which has surprised me a time or two.
Leak detectors are widely available.
 Re-Useable Water Leak Alarm-RWD21 - The Home Depot

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Accumulator tank - replace or not?
Reply #11 –
Quote from: hbn7hj  - 
I would give a link for the water detector

I've been using a Glentronics water alarm for over a year now.  The sensor is at the end of a long wire, so the sensor can be placed under the water pump and the alarm can be placed where it's easier to change the battery.

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Accumulator tank - replace or not?
Reply #12 –
Don't use one in the rig, but do at home in the laundry room. Note that when they alarm, there is no mute switch, so make it easy to either access and remove the battery, or access the sensor. It is painful to access and repair a leak while the alarm is shrieking in your ear!

Steve
2004 FL
2013 Honda Fit
Re: Accumulator tank - replace or not?
Reply #13 –

I have several of these:
Zircon Leak Alert Electronic Water Detectors Bonus Pack, Batteries Not...
I have one under the pump, one under the bathroom sink and one behind the toilet.  They emit a S-O-S beep when the contacts get wet.  The beep stops when you dry the contacts.  They use a single 9 volt battery.  Mine are 8 years old and still going strong.

Ken F in NM

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
'08 MB
Re: Accumulator tank - replace or not?
Reply #14 –
So... here's my concern with the water leak detectors mentioned so far...where do you plan to be when your out and about? In your LD 24/7?

Water leaks wait for no one. They don't say, "Hey I think I'll pour water all over the place when everyone is in the rig/house/basement so they can hear this darned alarm thingy".

I am curious if anyone has come back to their coach to find the alarm going off. A bit late at that point.

Mind you, I'm not saying, "Don't bother". The water detection alarm is pure brilliance at its simplest point. But then again, what if you're away?

I looked around the web and checked out and found at least one alarm that will sound the alarm via smart phone (possible audible as well).

The problem I see here is connectivity. Samsungs Smartthings requires a hub and a sensor an internet connection and power. Yikes!

Is there anything out there than can alert us while we are out and about? I'd like that one please.

Or...we could simply turn off the water when we're not using it.

Just sayin'

Kent
2015 27' RB "MissB.Haven"
Re: Accumulator tank - replace or not?
Reply #15 –
Quote from: Kent Heckethorn  - 
So... here's my concern with the water leak detectors mentioned so far...where do you plan to be when your out and about? In your LD 24/7?

Water leaks wait for no one. They don't say, "Hey I think I'll pour water all over the place when everyone is in the rig/house/basement so they can hear this darned alarm thingy".

I am curious if anyone has come back to their coach to find the alarm going off. A bit late at that point.

Mind you, I'm not saying, "Don't bother". The water detection alarm is pure brilliance at its simplest point. But then again, what if you're away?

I looked around the web and checked out and found at least one alarm that will sound the alarm via smart phone (possible audible as well).

The problem I see here is connectivity. Samsungs Smartthings requires a hub and a sensor an internet connection and power. Yikes!

Is there anything out there than can alert use while we are out and about? I'd like that one please.

Or...we could simply turn off the water when we're not using it.

Just sayin'

Kent


The obvious answer is turn the water off before leaving the rig. That has worked for us all these years. More than once we have seen water pouring out under an entry door while people were away from their rig.

We have had the alarm go off under the water pump a couple of times catching a problem early. The one under the sink has gone off when a bottle of liquid cleaner leaked.

Jim
Re: Accumulator tank - replace or not?
Reply #16 –
"The obvious answer is turn the water off before leaving the rig. That has worked for us all these years. More than once we have seen water pouring out under an entry door while people were away from their rig.

We have had the alarm go off under the water pump a couple of times catching a problem early. The one under the sink has gone off when a bottle of liquid cleaner leaked."

In the early years, we just turned off the pump switch as we left the coach, but later on added a twist of the outside faucet to the mix, thus eliminating (hopefully) the occasion of water going INTO the coach when we were not there.

Now that we are mostly in a S&B abode, we STILL turn off the water to the house if we intend to be gone all day - or longer.  Probably overkill, but having seen the overflow in others' rigs, and an up close and personal mini-flood in a different S&B home, we find that the few seconds it takes to turn a handle is time well spent. 

BTW, we HAD actually turned off the water prior to the flood.  A house minder turned it back on to water the trees, and then forgot to turn it back off.  Comes along freezing weather and the ice maker hose popped off and created a slow drip.

At that point, we tee'd off the water supply to INSIDE and OUTSIDE!!!

As for the alarm in the Lazy Daze . . . it went off when everything was totally dry.  We just yanked it for expediency.  Will investigate possibilities next time we are in the rig.

   Virtual hugs,

   Judie
Re: Accumulator tank - replace or not?
Reply #17 –
Judie,

Brilliant work. As I was reading I thought, "Tee the water to the house". Experience is a quick study.

Thanks for your input.

Prepping for Indian Cove next week. Should be nice weather, but keeping my fingers crossed.

Kent
2015 27' RB "MissB.Haven"
Re: Accumulator tank - replace or not?
Reply #18 –
Quote from: Kent Heckethorn  - 
I looked around the web and checked out and found at least one alarm that will sound the alarm via smart phone (possible audible as well).

So, what if cell connection is poor, or the app tanks? Simple is best. We never hook up to water, but if you do, turn off the faucet, and turn off the water pump when you leave. Turn off your phone to save the battery. Breathe a sigh of relief and head out to explore.

Steve
2004 FL
2013 Honda Fit
Re: Accumulator tank - replace or not?
Reply #19 –
Judie said, "At that point, we tee'd off the water supply to INSIDE and OUTSIDE!!!"

My brain cells aren't quite catching this...I turn off the H2O in the S & B when I leave for a trip (never thought about when just gone for the day, but that could certainly be long enough to create great misery)--it looks like it's just a regular outside faucet handle in the basement where the H2O comes in from the front yard.   The H2O meter is in the front yard, & I guess I could turn it off there, too, but I don't quite get the "tee'd off the water supply."  What kind of gadget/hydrant/etc. did you use?  Thx.

Lynne

Lynne
LDy Lulubelle, Green '05 31' TB
Lilly, the 4-Legged Alarm
Re: Accumulator tank - replace or not?
Reply #20 –
Hi Lynne. Here in San Diego, the street pressure in the water mains is quite high, since they also supply fire hydrants. Each house comes with a pressure regulator to reduce stress on your indoor plumbing. Many people 'Tee' off the incoming line to run their irrigation sprinklers. Here a couple hundred square feet of lawn, not acres. I actually put in a high flow separate regulator for my lawns to protect the schedule 40 plastic pipes. Low flow sprinkler heads put extra pressure on the pipes. I have separate 1/4 turn ball valves to close off each circuit, after the water company valve at the meter. RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Accumulator tank - replace or not?
Reply #21 –
Hi, Ron B--

Thx for that explanation.  I don't have a sprinkler system, but several of the neighbors do.  I guess I figured the pressure was managed at the meter where it comes off the city line to the house.  The fire hydrant between the neighbors & me (but in my yard), is about 30 feet past the meter--boy, I'd hate to think of the pressure required for the hydrant blowing something in the house...guess I'll call the H20 department & get some more education about my smalltown system...I'd not like a geyser inside or out because something wasn't tee'd off.   :P

Lynne
Lynne
LDy Lulubelle, Green '05 31' TB
Lilly, the 4-Legged Alarm