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paulz
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# Posted: 8 Jun 2022 04:40pm - Edited by: paulz
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I'm still on a quest for the 'rip the skin off your back' hot showers I get back at the city house. I think they say it's 80psi, and of course lots of flow.
At the cabin I have a Flojet 2.9GPM, 50PSI 12v pump. It is non adjustable, unlike the Shurflos. Browsing around, I see some like the SeaFlo 5.5GPM, 60PSI pump. I'm not sure an extra 10PSI is going to help much, and a shower head is nowhere near that GPM.
The relationship between flow and pressure confuses me. Seems the more restricted the flow, the higher the pressure, something like that. I replaced the shower head with a pressure gauge, and Flojet does hit 50, but as soon as I open a valve it drops way down, so how can they accurately advertise pressure? There are some cheapo $30 pumps on Amazon that advertise 130 PSI but only 6L a minute flow.
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NorthRick
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# Posted: 8 Jun 2022 05:37pm
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Quoting: paulz The relationship between flow and pressure confuses me. Seems the more restricted the flow, the higher the pressure, something like that. I replaced the shower head with a pressure gauge, and Flojet does hit 50, but as soon as I open a valve it drops way down, so how can they accurately advertise pressure? There are some cheapo $30 pumps on Amazon that advertise 130 PSI but only 6L a minute flow.
Come on Paul, you have to be old enough to know that advertisements can say almost anything and nobody will call them on it.
But you are right, pressure and flow are inversely related, one goes up and the other goes down.
A reputable pump manufacturer will have pump curve charts showing what pressure and flow you can expect at different heads. These pumps will cost more than $30.
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Nobadays
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# Posted: 8 Jun 2022 07:55pm
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I've thought about getting one of THESE
I've heard they do work well... lits of RV'ers use them. Just never heard a first hand accout.
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Brettny
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# Posted: 8 Jun 2022 08:16pm
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Your shower head should say what GPM it is. I would be suprised if it's more than 2.5gpm how ever I would also be suprised if a 2.9gpm pump is actualy putting 2.5gpm out at the shower head.
Have you filled a 5gal bucket and timed it? I would start there as it's a free test and a bench mark on where to go.
I also have a 2.9gpm pump and have used it for a shower before and can also say it's not really a whole lot of water. This was from a 55gal barrel at about 4ft lower than the shower head. I would double the GPM on the pump next time.
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paulz
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# Posted: 8 Jun 2022 08:36pm - Edited by: paulz
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I've tried multiple shower heads, including the ones I use at the city. I believe you are right Brett, I don't think it's over 2.5 a minute on any of them. With the adjustable ones, at a high flow setting the pump will run constantly but the pressure is not there. Turning to a lower flow setting gets more pressure but then pump cycles constantly.
Seems to me I'm looking for a pump with higher pressure more than flow, but as Rick said the two are inversely related. I did see a couple of curve charts online, looking into that.
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gcrank1
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# Posted: 8 Jun 2022 09:17pm
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I like a Hot, Strong shower too; but with an old country house system it has been kinda weak.
1st, I think you need a pressure tank.
I just adjusted the pressure switch on ours at home that has been puny for too long (think the tank is 30gal). I had replaced the switch years ago when the old one failed and we just 'got by'.
The shower head is one of those cheap sunflower type, about 6" dia. and I took the reducer out right away after trying it a bit. It has been the best of the bunch weve had.
Ive got the pressure switch now set at 45psi-on, 60psi-off. In the shower it feels pretty good and steady, only a tad light before the pump switches on.
The tank 'buffers' the pressure in a meaningful way. It looks like most pressure switches have a 20psi differential, that was too much for me. And the low end at 30-35psi was too weak. I liked a 10psi diff but that made our submersible pump cycle too much; the 15psi diff is pretty nice.
Btw, home for us the past 35ish yrs is a 940sf cottage, the off grid, dry cabin is 380ish with no shower (unless we rig up the big sprinkler can or stand under the eve when it rains).
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paulz
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# Posted: 10 Jun 2022 09:11am
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Quoting: gcrank1 I just adjusted the pressure switch on ours at home that has been puny for too long (think the tank is 30gal). I had replaced the switch years ago when the old one failed and we just 'got by'. The shower h
You have a 30 gallon pressure tank? With a switch? The ones I've seen for 12v RV type systems, basically what I have, are a gallon or so, and have an air pressure adjustment.
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gcrank1
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# Posted: 10 Jun 2022 10:21am
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I should have emphasized its the 'home' system, 1950's technology in a pre-1900 remodeled school house.
I dont know what a typical rv type 12v pump can pressurize to but in my limited knowledge my guess is a small tank and a weak pump is your nemisis.
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travellerw
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# Posted: 10 Jun 2022 10:59am
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Quoting: paulz You have a 30 gallon pressure tank? With a switch? The ones I've seen for 12v RV type systems, basically what I have, are a gallon or so, and have an air pressure adjustment.
We had one of those in our RV and pulled it out to instead install a 5 gallon domestic pressure tank. We then installed a "Square-D" type pressure switch, bypassing the pumps pressure switch.
We didn't do any scientific measurements when we set it up, just adjusted the pressure by feel. Both the switch and tank can be adjusted. We adjusted the low cut-ON pressure switch while turning the shower on and off. Once it felt like good flow and pressure from the shower head, I called that good. I pumped up the tank to somewhere in between the low and high cut-off. It provides about 20 seconds of flow before the pump kicks in. This reduces the number of pump cycles in the night when the toilet is flushed. It also means the pump starts up and runs constantly to fill the pressure tank instead of cycling on-off-on-off-on-off. I find that is easier to sleep through. That was over 10 years ago now.
We also have an oxygenics shower head as mentioned above. I think it helps with a good shower feel, but its main benefit is the low water use. It really helps conserve water and still have a nice shower.
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paulz
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# Posted: 11 Jun 2022 11:11am - Edited by: paulz
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Quoting: Nobadays I've thought about getting one of THESE
Interesting. Doesn't say what the 'cutting edge technology' is that I saw, but if it works..
Here's my current crop of cabin shower heads, all adjustable. Some do work better that others.
I have something in the works for next week..
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gcrank1
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# Posted: 11 Jun 2022 05:26pm
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Well, fwiw, after all those years of having a puny shower, and trying 3 different heads, the solution for us was to get that tank pressure up.
Im thinking it might be kinda like HP, want better performance?, get more!
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