Fesh water pump recommendation?

[alpine44]

Looking for a reliable and not too expensive 12v pump for fresh water system with shower.

Any recommendations based on long term use?

[PNW_Steve]

Flojet

https://www.amazon.com/Shurflo-2088-...NsaWNrPXRydWU=

[JDOnTheGo]

Ditto. Also consider a pressure tank so the pump doesn't have to work every time you open a faucet.

I keep a spare pump on hand, just in case. I destroyed one once due to freezing (the pump end, not the motor) but otherwise never had an issue with them.

[PNW_Steve]

Originally Posted by JDOnTheGo

Ditto. Also consider a pressure tank so the pump doesn't have to work every time you open a faucet.

I keep a spare pump on hand, just in case. I destroyed one once due to freezing (the pump end, not the motor) but otherwise never had an issue with them.

+1

I set out in my first bus without a pressure tank. Shortly after I went out and got one. I wouldn't do without now.

I carry a spare rebuild kit for my water pump on hand. I may consider carrying a full spare with me. Given the slim availability of 24v pumps while on the road a complete spare may be the best route to go.

[kazetsukai]

Originally Posted by PNW_Steve

+1

+2


Mine came with a pressure tank and the water will run continuously w/o the pump for 20-30s. The pump consumes about 240W while running, and without a pressure tank its possible the setup will sputter.

[PNW_Steve]

Whet I experienced with no pressure tank is what I would describe as "short cycling ".

The pump came on every few seconds and then shut off for a few seconds. This caused varying water pressure and that caused temperature variations in the shower. No fun....

[Drew Bru]

Originally Posted by PNW_Steve

Whet I experienced with no pressure tank is what I would describe as "short cycling ".

The pump came on every few seconds and then shut off for a few seconds. This caused varying water pressure and that caused temperature variations in the shower. No fun....

And the pressure tank is dead easy to install, simple in design, and relatively inexpensive. Keeps the pump from cycling when you need just a bit of water to rinse your hands or toothbrush or something.

[alpine44]

Thanks everyone for the comments and suggestions.

I ordered two Shurflo pumps and accumulator tanks for this system


Top third of the drawing is the potable water system.

Middle section of the drawing is the recirculating shower. Water from that tank will also be used to flush the toilet. There is a one way connection to the potable water circuit if the level in the recirculation tank gets too low. Not shown in the drawing is a small corner sink in the bathroom through which the recirculation tank can be refilled. The kitchen has a separate grey water tank.

Bottom third of the drawing is the hydronic heating system with heat exchangers for warm water. There will be a small electrically heated reservoir (a hacked 500W Kats pre-heater) for small amounts of warm water in the kitchen.

All water lines are 1/2" PEX with some flexible hoses where needed.

[kazetsukai]

Whoa- that looks cool.

Originally Posted by alpine44

Middle section of the drawing is the recirculating shower.

I've had problems designing one: First, you do need some "clean" water initially. The grey tank will be empty at some point- how do you handle that scenario? Second, would it really be safe/advisable to send (filtered) grey water back into the main plumbing? Wouldn't I have to separate the shower in its own plumbing loop, necessitating its own heater, etc? Not sure I want used shower water in my sink faucet! (looks like some check valves may keep the grey water to the shower, but does it reheat, ever?)


Any thoughts on how you designed this appreciated, it would really make water stretch a long way.

[alpine44]

Originally Posted by kazetsukai

Whoa- that looks cool.


I've had problems designing one: First, you do need some "clean" water initially. The grey tank will be empty at some point- how do you handle that scenario? Second, would it really be safe/advisable to send (filtered) grey water back into the main plumbing? Wouldn't I have to separate the shower in its own plumbing loop, necessitating its own heater, etc? Not sure I want used shower water in my sink faucet! (looks like some check valves may keep the grey water to the shower, but does it reheat, ever?)


Any thoughts on how you designed this appreciated, it would really make water stretch a long way.

I am still working on the details to make this as simple as possible.

The kitchen faucet is only connected to the potable water tank, has its own heat exchanger and will never get in contact with the recirculation water. The kitchen sink will drain into a separate holding tank since this water contains food residue.

The recirculation system has its own pump and heat exchanger for warm water in the shower.

I think I will hook the corner sink in the bathroom to the potable supply but have it drain into the recirculation tank. Initially, the recirculation tank will be filled with fresh water. As this water is depleted by the toilet flush, I can run the bathroom corner sink to replenish it. That would omit the problematic check valve bypass between potable and recirculating loop.

[alpine44]

Latest version:


Recirculating tank is now replenished via bathroom sink, that has a faucet connected to the potable water system.

The whole plumbing distribution and zone valves for the hydronic heat are going to be installed in a hollow wall separating the shower from the living quarters. Opposite side of the wall holds the shower valve and corner sink. The Espar heater is mounted under-floor in the same location.

With everything concentrated there, I only need to run one line through the floor insulation to the toilet and two lines to the kitchen on the opposite side of the vehicle. Both runs will be adjacent to loops of the floor heat.

[kazetsukai]

Originally Posted by alpine44

Latest version:

Much cleaner diagram. As long as you can make assumptions about what will go into the recirculation tank (no food residue), I don't see any of the above raised issues in this version. The first thing I thought when looking at the recirculation loop, specifically filtration was oils and animal fats from the kitchen sink (I currently have one, single holding tank with a diverter valve for situations where the shower water can drain directly to the ground) clogging that filter almost instantaneously.



For me to do what you're doing (lucky!), I'd need a separate holding tank _just_ for shower water, and because a heat exchanger loop presents other challenges (the heat loop needs to be circulating hot water to work), I'd probably just opt for a second water heater. Your solution of draining the bathroom sink to the tank to "seed" it is great.



And then the ultimate problem if I was to try this: All of my plumbing is in the cabin intentionally for winter weather- but I cannot do this for drained shower water. I'd have to do something to ensure it didn't freeze, and antifreeze isn't an option in this scenario.

Originally Posted by alpine44

The whole plumbing distribution and zone valves for the hydronic heat are going to be installed in a hollow wall separating the shower from the living quarters.

My hydro heat is currently in series, which is a problem if I want to focus heat a certain part of the cabin. If I could do zones, that would be pretty awesome. What kind of valves are you using?

[alpine44]

Originally Posted by kazetsukai

Much cleaner diagram. As long as you can make assumptions about what will go into the recirculation tank (no food residue), I don't see any of the above raised issues in this version. The first thing I thought when looking at the recirculation loop, specifically filtration was oils and animal fats from the kitchen sink (I currently have one, single holding tank with a diverter valve for situations where the shower water can drain directly to the ground) clogging that filter almost instantaneously.

For me to do what you're doing (lucky!), I'd need a separate holding tank _just_ for shower water, and because a heat exchanger loop presents other challenges (the heat loop needs to be circulating hot water to work), I'd probably just opt for a second water heater. Your solution of draining the bathroom sink to the tank to "seed" it is great.



And then the ultimate problem if I was to try this: All of my plumbing is in the cabin intentionally for winter weather- but I cannot do this for drained shower water. I'd have to do something to ensure it didn't freeze, and antifreeze isn't an option in this scenario.



My hydro heat is currently in series, which is a problem if I want to focus heat a certain part of the cabin. If I could do zones, that would be pretty awesome. What kind of valves are you using?

I am going to use a standard PEX radiant heat manifold with manual valves. The valves are for balancing the system, for summer use of the Espar as a water heater, and for repairs.

The final filter in the recirculation loop is activated charcoal. That would deal with some kitchen waste but I need to balance the weight across the width of the vehicle and that's why the kitchen had a separate grey tank already before I decided to go with a recirculating shower.

The fresh and grey tanks will be insulated and have a pad heater underneath.

I'll try to get instant hot water in the kitchen by putting a well insulated Kats tank heater in the hot water line coming from the heat exchanger. That holds 1/3 gallon and has a built-in thermostat. The usual point-of-use water heaters cost three times as much and suck even more amps when heating. I am also certain that I can do a much better insulation job with the smaller Kats. What matters in the end is the continuous heat loss of a tank-type water heater.

[Jolly Roger bus 223]

heck of a design you are going for.
a few things that i see and maybe you didnt include to keep the drawing simplified is with your design there are some places that you need check valves and it could work fine.
the radiant heat water system through heat exchanger or radiant flooring usually wants 160-180 water but a normal home only wants 110-120 at a sink shower or wherever.
they do make point of use mixing valves that would work well for your scenario except at your kitchen sink loop. for instantaneous water there you need a pump to keep the water moving in that loop and then a point of use mixing valve to temper the water.
forget that sorry had to find your diagram again?
the cold water should not be going to a heat exchanger it should be going directly to your water heater with a check valve and expansion tank on the entering side of your heater and tank after check valve then a recirc pump and line from the farthest point to keep the entire hot water system instantaneous and a cheap little aquastat can be used to maintain temps.
does your water heater have a pump built into it.
most of your idea looks doable but the cold water from the kitchen sink to the heat exchanger aint gonna work cause without a check valve one the cold water line is opened on the faucet the heat exchanger temp is going to over come the cold water temp. time depends on length of pipe run but that also takes pressure water and pressure away from your radiant heat exchanger which could airlock the coils unless you have auto air vents installed for when the pressure comes back.
i have a few more but will shut up for now? life happens gotta deal with it.
good luck

[alpine44]

Originally Posted by Jolly Roger bus 223

heck of a design you are going for.
a few things that i see and maybe you didnt include to keep the drawing simplified is with your design there are some places that you need check valves and it could work fine.
the radiant heat water system through heat exchanger or radiant flooring usually wants 160-180 water but a normal home only wants 110-120 at a sink shower or wherever.
they do make point of use mixing valves that would work well for your scenario except at your kitchen sink loop. for instantaneous water there you need a pump to keep the water moving in that loop and then a point of use mixing valve to temper the water.
forget that sorry had to find your diagram again?
the cold water should not be going to a heat exchanger it should be going directly to your water heater with a check valve and expansion tank on the entering side of your heater and tank after check valve then a recirc pump and line from the farthest point to keep the entire hot water system instantaneous and a cheap little aquastat can be used to maintain temps.
does your water heater have a pump built into it.
most of your idea looks doable but the cold water from the kitchen sink to the heat exchanger aint gonna work cause without a check valve one the cold water line is opened on the faucet the heat exchanger temp is going to over come the cold water temp. time depends on length of pipe run but that also takes pressure water and pressure away from your radiant heat exchanger which could airlock the coils unless you have auto air vents installed for when the pressure comes back.
i have a few more but will shut up for now? life happens gotta deal with it.
good luck

You are correct, the Espar heater will switch between 2400W and 5000W to keep the loop temperature between 165F and 185F. That's great for the radiant floor heat but too much for hot water even if there is a temperature loss in the heat exchanger.

To make this safe, I plan on using European-style thermostatic mixing valves on the sinks and the shower. These valves maintain a selected temperature regardless of the temperature/pressure of the feed water and serve as an anti-scald protection. The Chinese knock-offs are so cheap and easy to change that I'll keep a spare for the road.

There is no need for check valves in the hot and cold branches. The water will follow the path of lowest resistance set by the mixing valve.

Instant hot water in the kitchen will come from a small, electric water heater very close to the faucet. If I need a lot of warm water, I will have to wait for the Espar to fire up and the heat exchanger to warm up.

[Frogpondfoug]

Seaflo 12V 3.0 GPM 55 PSI Water Pressure Diaphragm Pump with Internal Bypass Valve to reduce cycling https://www.amazon.ca/dp/B01CQ7DD0S/ref=cm_sw_r_cp_apa_i_oEJSDbPK1BDTV




I used this one, quite and mean little pump works greak on demand. I plumbed with 1/2 pex. Good got the price

[Rustynails]

What’s the best choice for my new skoolie water pump? A 12v or 24v? What’s the advantages?
Thank you very much!!
Frank

[Danjo]

Originally Posted by Rustynails

What’s the best choice for my new skoolie water pump? A 12v or 24v? What’s the advantages?
Thank you very much!!
Frank

The only advantage I see to running 24v anything is either to match your house voltage and/or use smaller gauge wiring for long runs. In the case of an RV water pump, I think it would only be the former reason