RV style pump to fill a 86 gallon bladder tank?

[JamesHird]

I need to pressurise water from a 1500 gallon water tank.
We use between 50-100 gallons per day.
Practically no head pressure
I have bought a 86 gallon bladder tank.

My question is, would a 120v diaphram pump (RV pump style) be suitable for pressurising this tank or do I need something beefier?

I estimate a pressure tank that size should provide 30/40 gallons of water before the pump kicks on to re pressurise it.

I have a 1hp 240v jet pump still in its box that I was intending to install but the more I think about it the more I think something with such a high current draw is not necessary.

Can anyone with experience in this field pass on some knowledge?

Thanks

 

[speedsenft]

Check the rated duty cycle, most of them are rated for 5-10min on, then a cool down of 15 min. I transfer 60 gallons at a time to a storage tank. It takes 10 min or so. The pump gets damn hot. There may be ones out there that can run continuously.

 

[sparrowhawk]

I use a Shurflo 2088-594-154 Industrial Water Pump. I actually use 2 of them in parallel, I tried 1 pump but I didn't get the pressure and volume I wanted. I don't have have a bladder tank and just draw water from my 500 gallon tank that I refill about once a week. There would be no issue with pressurizing your tank although you really don't need it. I have have used 1 of these pumps for several years and one time I let it run dry for about 6 hours with no ill effects. In fact I just pulled it from service to keep as a backup if one of the other pumps fails.​

I chose to use this style pump because of their low power draw. I believe they're 1/10 horse power so should work fine for almost any solar setup..

 

[JamesHird]

Check the rated duty cycle, most of them are rated for 5-10min on, then a cool down of 15 min. I transfer 60 gallons at a time to a storage tank. It takes 10 min or so. The pump gets damn hot. There may be ones out there that can run continuously.

Good point. I'll check that.
I pump 35 gallons into my 5th wheel tank with one at the moment. it gets pretty hot after that. It is pumping the water 100ft slightly uphill through a 3/4 garden hose.

 

[JamesHird]

I use a Shurflo 2088-594-154 Industrial Water Pump. I actually use 2 of them in parallel, I tried 1 pump but I didn't get the pressure and volume I wanted. I don't have have a bladder tank and just draw water from my 500 gallon tank that I refill about once a week. There would be no issue with pressurizing your tank although you really don't need it. I have have used 1 of these pumps for several years and one time I let it run dry for about 6 hours with no ill effects. In fact I just pulled it from service to keep as a backup if one of the other pumps fails.​

I chose to use this style pump because of their low power draw. I believe they're 1/10 horse power so should work fine for almost any solar

I also let mine run dry for god knows how many hours and its fine. Slightly louder I have to say. I've used and abused that pump and it still runs. Thats why I want to incorporate that type of pump into my new set up.
Last year I let that pump freeze up completely at least three or four times. Its still running now.

We want the pressure tank so the pump doesn't have to kick on every time we turn the tap on, especially at night.

I could parallel two pumps into the pressure tank and it would still be less than the draw of a jet pump.
How much distance in between the two pumps? Have you found and drawbacks from running two pumpsin parallel?

 

[sparrowhawk]

I also let mine run dry for god knows how many hours and its fine. Slightly louder I have to say. I've used and abused that pump and it still runs. Thats why I want to incorporate that type of pump into my new set up.
Last year I let that pump freeze up completely at least three or four times. Its still running now.

We want the pressure tank so the pump doesn't have to kick on every time we turn the tap on, especially at night.

I could parallel two pumps into the pressure tank and it would still be less than the draw of a jet pump.
How much distance in between the two pumps? Have you found and drawbacks from running two pumpsin parallel?

The two pumps are right next to each other. The main drawback is the noise. There's significantly more noise for me when running two pumps. It causes the main input pipe to rattle which I think may be from cavitation. I have them connected with flexible hose both on the input & output sides but it doesn't help with the noise. The noise is mainly being generated where the pipe enters the wall. It's right up against the stud and it rattles against it. If I had more clearance around the pipe I could isolate it and dampen some of the noise.
I have considered adding a pressure tank for the same reasons as yours. I decided against it for two reasons. One is the cost. I'm living far below the poverty line so I'm literally dirt poor and a good tank cost far than I can afford. And two is that I might be able to swing getting a cheaper tank, but they seem to have a high rate of failure, mainly from rusting through. Now the rust throughs may be from not properly isolating the steel tank from the copper plumbing, but I'm not willing to take a chance on one.

 

[JamesHird]

The two pumps are right next to each other. The main drawback is the noise. There's significantly more noise for me when running two pumps. It causes the main input pipe to rattle which I think may be from cavitation. I have them connected with flexible hose both on the input & output sides but it doesn't help with the noise. The noise is mainly being generated where the pipe enters the wall. It's right up against the stud and it rattles against it. If I had more clearance around the pipe I could isolate it and dampen some of the noise.
I have considered adding a pressure tank for the same reasons as yours. I decided against it for two reasons. One is the cost. I'm living far below the poverty line so I'm literally dirt poor and a good tank cost far than I can afford. And two is that I might be able to swing getting a cheaper tank, but they seem to have a high rate of failure, mainly from rusting through. Now the rust throughs may be from not properly isolating the steel tank from the copper plumbing, but I'm not willing to take a chance on one.

I ordered a 120v diaphragm pump. I’m going to try it with one pump to begin with, see how long it takes to pressurize the tank. I’ll design the system so there is space to add another pump if necessary.
I need to do some research into cavitation. See how to reduce the affects

 

[Checkthisout]

Add a small pressure tank to dampen the output pulses and of course make sure all pipes are secured.

The 12v seafloor pumps with bypass work good.

Getting a 120v model is better simply because your flow rate doesn't change as your battery voltage fluctuates throughout the day.

 

[sparrowhawk]

Add a small pressure tank to dampen the output pulses and of course make sure all pipes are secured.

The 12v seafloor pumps with bypass work good.

Getting a 120v model is better simply because your flow rate doesn't change as your battery voltage fluctuates throughout the day.

In my system I have never felt any pulses at any of the faucest or shower heads with one or both pumps running. Perhaps because the water in the pipes act to dampen the pulses.

 

[Checkthisout]

In my system I have never felt any pulses at any of the faucest or shower heads with one or both pumps running. Perhaps because the water in the pipes act to dampen the pulses.

Not talking about feeling water pulses. Talking about the output pulses making pipes rattle.

 

[12VoltInstalls]

We want the pressure tank so the pump doesn't have to kick on every time we turn the tap on, especially at night.

Spring buffered pump. And then put a 3/4 pipe on a Tee about 48” tall to buffer hammer

 

[littleharbor2]

I use a 120 vac Sea Flo 5.5 gpm. pump to transfer 1000 litres from a tote to a rooftop tank here at home. does a great job without ever getting hot.

 

[Bobert]

In rv applications sometimes people will use an accumulator to soften the rattling of the pipe from the pump and decrease the frequency of the cycling of the pump.

 

[12VoltInstalls]

In rv applications sometimes people will use an accumulator to soften the rattling of the pipe from the pump and decrease the frequency of the cycling of the pump.

The pump I linked has a spring-buffered no-surge feature that effectively stops hammer and rattle. If using pex, 99.44% of ‘rattles’ are from not securing the pipes.

 

[sparrowhawk]

The pump I linked has a spring-buffered no-surge feature that effectively stops hammer and rattle. If using pex, 99.44% of ‘rattles’ are from not securing the pipes.

I agree and in my case the pipe is banging against a stud. To secure the pipe I would have to open the wall up and don't want to do that so I think I will live with the noise. When only using one pump the pipe doesn't even move at all. So the pumps are interacting together to cause more vibration then I would expect.
The reason suspect cavitation may have something to do with it because I'm getting air in the pipes and it's not sucking air in from the outside. It's a very small amout that's only noticable when the toilets are filling. And although a pressure tank may help a little, my concern with that would be air getting trapped in the tank and eventually rendering it useless.

 

[12VoltInstalls]

And although a pressure tank may help a little, my concern with that would be air getting trapped in the tank and eventually rendering it useless.

Air in the tank is what makes it work though

 

[sparrowhawk]

Air in the tank is what makes it work though

Yes and humans need air to live and there's air in water, and yet if you submerge us in water long enough we expire.

 

[12VoltInstalls]

Air in the tank is what makes it work though

Most of the time like basically always these days the pressure tank is a bladder that holds air and maintains a volume of water at pressure.
Any air in the water side of the bladder will just add to the pressure reservoir.

Home furnaces when I was a kid often had “pressure tanks” that periodically needed draining of water or repressurizing with air- no bladder. 5-10, sometimes 15psi. “Expansion tank”
Same principle- I was just trying to allay your concern.

 

[sparrowhawk]

Most of the time like basically always these days the pressure tank is a bladder that holds air and maintains a volume of water at pressure.
Any air in the water side of the bladder will just add to the pressure reservoir.

Home furnaces when I was a kid often had “pressure tanks” that periodically needed draining of water or repressurizing with air- no bladder. 5-10, sometimes 15psi. “Expansion tank”
Same principle- I was just trying to allay your concern.

It really has nothing to do with the bladder as it's a separate air charged chamber.

What's most likely to happen is air entering the tank will rise to the top and displace water. Eventually replacing most the water with air. The air would need to be purged every so often. The tank may continually purge some of the air when it's in use but how much depends on at what point the pump kicks in. It's likely some air will remain in the tank until all the pressure is bled off.

 

[12VoltInstalls]

really has nothing to do with the bladder as it's a separate air charged chamber

Yes. As I described.
My points were A) air won’t disable the tank and B) any air tends to absorb into the water over time in general.
But any air on the wet side of the bladder will still act to provide pressure, just without the water reserve volume.