On Demand Water Pump and Accumulator

kiwaon · 10-17-2013, 07:23 AM

Has anyone installed an accumulator on their unit that is equipped with an on demand water pump? Our 2012 is equipped with an on 'demand pump'.

It would seem the on demand pump must have the 'on' and 'off' pressure parameters set close to one another, and would probably be of little value to install an accumulator, or am I wrong?

On my old unit, with no on demand pump, I found the accumulator (5 gals.) especially useful at night when someone uses the bathroom. You could normally get 2 to 3 flushes before the pump would come on, or more if you turned the pump off at night.

I would welcome hearing from anyone who has tried this, or has ideas.

Thanks and have a great day.

Cosmik Debris · 10-17-2013, 07:54 AM

By "on demand" are you talking about a pump with pressure adjustment? I knew that I had read about using an accumulator with one and found the forum.
http://lanceowners.hoop.la/topic/shu...008-adjustment
What this person found was that there was no need for an accumulator with this pump.
On my old TT I installed an accumulator and it was a nice mod, but haven't looked into do it on my new 2013 Jayco. Your question has me thinking that I should check the model of pump first to see if the tank would be needed.

mcfarmall · 10-17-2013, 08:19 AM

To me, on demand means that when you call for water the pump turns on and supplies it. An accumulator tank will work fine with an "on demand" pump such as is installed on RV's. Look in the mods section for my write up on my accumulator tank install. I bought a 2 gallon captive air "bladder" tank off Ebay for under $20 I think and simply tee'd it into the cold water line under the bathroom lavatory cabinet. Works awesome! My pump doesn't cycle on/off every time you crack a faucet and I can flush the toilet several times in the night without the pump coming on. I'll never go back to a typical pumping system.

**Crabman** · 10-17-2013, 09:16 AM

Here is mine. The shurflo accumulator tank hooked up to a shurflo pump:

msturtz · 10-17-2013, 09:20 AM

Quote:

Originally Posted by Crabman

Here is mine. The shurflo accumulator tank hooked up to a shurflo pump:

The foam isolation is a nice touch! I have a 2 gallon accumulator tank.

**Crabman** · 10-17-2013, 09:22 AM

Two gallons would certainly be better, even less pump cycling.

TeamFoxy · 10-18-2013, 01:41 PM

I can see having the accumulator on a TT if you operate on tanks most of the time, but a waste of time if you are at campsites with a city water connection most of the time.

**Crabman** · 10-18-2013, 01:58 PM

Quote:

Originally Posted by TeamFoxy

I can see having the accumulator on a TT if you operate on tanks most of the time, but a waste of time if you are at campsites with a city water connection most of the time.

Very true. Many of the state parks here have electric only, no water hookups so it makes sense for us.

dmax_83 · 10-18-2013, 02:57 PM

I also have a Surflo pump and their matching accumulator. Since 99% of my camping is without water hookups, this really cuts down on the short cycling of the pump. It is too small to keep the pump from cycling if you flush the toilet though, but it was all I had room for. The water flow is also much more consistent now too, I would recommend the upgrade to anyone.

msturtz · 10-18-2013, 03:40 PM

Quote:

Originally Posted by TeamFoxy

I can see having the accumulator on a TT if you operate on tanks most of the time, but a waste of time if you are at campsites with a city water connection most of the time.

I use my RV while in route. An accumulator can prevent the pump from running dry. It also allows me to wash hands or use the toilet without turning the pump on.

kiwaon · 10-18-2013, 04:30 PM

Quote:

Originally Posted by Cosmik Debris

By "on demand" are you talking about a pump with pressure adjustment? I knew that I had read about using an accumulator with one and found the forum.
http://lanceowners.hoop.la/topic/shu...008-adjustment
What this person found was that there was no need for an accumulator with this pump.
On my old TT I installed an accumulator and it was a nice mod, but haven't looked into do it on my new 2013 Jayco. Your question has me thinking that I should check the model of pump first to see if the tank would be needed.

Cosmic, thanks for the link to the Lance forum. The 'on demand' pump on my current unit, unlike my previous one, has no shut off and start up pressure setting. ( The old unit's pump shut off at 42 lbs and came back on at 28, thus making an accumulator useful). My new one simply comes on when I open the tap and stays on until I shut it regardless of the flow, thus not requiring an accumulator. I guess if I really wanted the pump not to come on at night but still have water for a few flushes I could still install the accumulator and shut the pump of at night.

cheers and have a great day.

msturtz · 10-18-2013, 05:20 PM

The pump on my new Greyhawk is a demand pump. Most of these pumps use a spring return valve that allows water to return to the low pressure side when you have the tap partially open. That said it doesn't eliminate the need for an accumulator. The pump is still running and using (wasting) energy. An accumulator allows the pump to stop running when the tank is full even if water is still being used. The pump will run at full volume fill up the tank then stop until the pressure drops below the pump set point. This is much more efficient and better for the pump. There are variable speed pumps that are incompatible with accumulators. If you have one of those then you can't use an accumulator.

northmeck0255 · 11-02-2013, 05:07 AM

Quote:

Originally Posted by TeamFoxy

I can see having the accumulator on a TT if you operate on tanks most of the time, but a waste of time if you are at campsites with a city water connection most of the time.

We always use the installed pump, even at a FHU site. It protects us from damaging pressure spikes, and we only use campground water to refill the onboard tank. Walking away from an RV and leaving it connected to an inexhaustible water supply isn't a good idea. Many an RV'er has returned from dinner to find water running out the door. By running on the onboard tank/pump and turning it off when we leave, we lessen the risk of damage. The worst case scenario would be springing a leak, in which case the residual pressure in the line would seep some water out, but there is no chance for major flooding.

troutslayer · 11-02-2013, 09:52 AM

Quote:

Originally Posted by northmeck0255

We always use the installed pump, even at a FHU site. It protects us from damaging pressure spikes, and we only use campground water to refill the onboard tank. Walking away from an RV and leaving it connected to an inexhaustible water supply isn't a good idea. Many an RV'er has returned from dinner to find water running out the door. By running on the onboard tank/pump and turning it off when we leave, we lessen the risk of damage. The worst case scenario would be springing a leak, in which case the residual pressure in the line would seep some water out, but there is no chance for major flooding.

I heard of an incident where a cat hit the kitchen fawcet lever, the sink filled and overflowed which flooded the camper. Ever since hearing this story, we have always turn the water spigot off when leaving our 5er.

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