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Small Cabin Forum / Off-Grid Living / On demand pump and water heater
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Rickkrus
Member
# Posted: 6 Aug 2019 12:13
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Looking for suggestions. I have a 250 gallon tank with a 20 gallon pressure tank. Need help choosing an on demand pump and water heater. Going to be solar powered.

FishHog
Member
# Posted: 6 Aug 2019 13:24
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Eccotemp L10 and the shuflo pump package is pretty hard to beat for the price

Brettny
Member
# Posted: 6 Aug 2019 15:21
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The ecotemp units require alot of pressure and dont have alot of temp rise. The manufacures like to put things like L5, L7 or L10 on them but all that really matters is the minimum pressure and the temperature rise at a specific GPM.



We have a 3.9gpm pump and a iheat heater. I dont think i ever actualy get more than 2.5gpm out of this pump even if its pumping with only 4ft head.

ICC
Member
# Posted: 6 Aug 2019 16:46
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Brettny is correct to mention temperature rise. Every on demand heater should have a chart or table that shows the number of degrees rise in water temperature for a few different flow rates. Often it can be impossible to get the water warmed enough with the volume rate you want. Check the coldest inlet temperature that is likely. Also important to check operating pressure requirements.

Rickkrus, you have a pressure tank but no pump with it?

For low volume uses one of the Shurflo or Flojet RV type pumps work great. No pressure tank needed. They switch on and off whenever water is used by opening the tap or valve.

aktundra
Member
# Posted: 6 Aug 2019 21:55
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I’m rather dissatisfied with Shurflo. 3 pumps in 4 years... including two in the last year. We only use the pump with Eccotemp water in the summer and not full time at the cabin.

Getting the right pressure for the eccotemp is important. Honestly, I’m looking for better options now.

darz5150
Member
# Posted: 6 Aug 2019 22:42
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Quoting: aktundra

I’m rather dissatisfied with Shurflo.

Wow. That's a lot of pumps.
I recently replaced one from 2011 that pumped at least 600 gallons per month year round. I have another that is in the bathroom that feeds kitchen and bathroom sink plus a shower that has been in use since around 2006.
Did yours quit pumping or did the motor fail? I won't buy anything but shurflo. You got me wondering what went wrong with your pumps. We live full time at our place. The pump I just replaced got used everyday. Even in the winter when it was so cold that the inlet screen would get clogged because the water would ice up in the hose between the water wagon and the inside tank.
What do you think went wrong?
And what pump are you going to use now?

FishHog
Member
# Posted: 7 Aug 2019 08:52
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I’m going on year 5 with my setup with no issues. I guess I don’t need a ton of water flow but I run my L10 at the Lowest water flow setting and can shower comfortably when I have a skim of ice in my water tank or when it’s at 75deg in the summer just by adjusting the temp knob in the L10

Brettny
Member
# Posted: 7 Aug 2019 09:18 - Edited by: Brettny
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Are you getting the pumps with a small motor or larger one?

I was wrong with my inital GPM. Its a 2.8gpm @ 0ft head. Most household showers are 2gpm at 30-50psi.
20170127_102324.jpg
20170127_102324.jpg


Ontario lakeside
Member
# Posted: 7 Aug 2019 09:52
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We have had good luck with our shurflow-ecotemp combo. No issues for 4 years

ICC
Member
# Posted: 7 Aug 2019 10:05
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I ha e used Shurflo pimps in RV's for decades and a few others in a small line cabin and other utility uses. I have never had a motor fail. I had one stop holding pressure because of dirt getting into the valve body. Another failed when I did not drain it and it froze. For that I bought a repair kit.

What or how fails on yours aktundra?

aktundra
Member
# Posted: 8 Aug 2019 20:55 - Edited by: aktundra
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I also use mine on the lowest water setting.

Shurflo 4008 - The one just went dead. I couldn't get anything from it. I tried everything thing from pressure switch to fuses/wiring/switches. I tore it apart, and nothing. Pump looked fine. I run two filters prior to the pump and these weren't clogged either. This pump lasted the longest. When this was running, the Eccotemp/Shurflo combo was great unless the batteries voltage dropped too much (really needed topped off batteries, solution since been solar/battery system). Edit to the original post - this was purchased in 2014, and was the primary pump, so 5 years is pretty good.

The other was sporadic with output, like surging with very little pressure, almost like it couldn't get primed. This happened this summer and I played with it for a bit, but ultimately swapped it out until I can take the time to mess with it. This pump was less than 2 summers old.

My third pump, to be fair, was probably my fault. I cracked in the inlet. I wish this weren't plastic.

My replacement? Another Shurflo pump. They are some of the most efficient pumps and I guess worth the $80-100 every couple of years.

Which Shurflo models are you guys running? I'm hoping the newest one I got is the last one for a while.

ICC
Member
# Posted: 8 Aug 2019 21:37 - Edited by: ICC
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Quoting: aktundra
My third pump, to be fair, was probably my fault. I cracked in the inlet. I wish this weren't plastic.


I often add a brass adapter so I can very carefully install that once and then any subsequent disconnections and reconnections are done at the brass threads. I remove the pumps when I winterize the RV or the line cabin. Then blow air through everything. So I do remove and replace several times a year especially if we make trips in the depth of winter.

I've mostly used the 4008 but the RV has a 4048

I've also had that cap end crack from freezing water

aktundra
Member
# Posted: 8 Aug 2019 22:07
Reply 


The brass adapter is smart and I will follow. I also remove and replace the lines and blow air through so the get removed fairly often.

darz5150
Member
# Posted: 8 Aug 2019 22:32
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4008.

ICC
Member
# Posted: 8 Aug 2019 23:00
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And for the water lines that connect to the pump, I use S/S braid-covered faucet supply lines with metal threaded ends, No more cross-threading plastic parts.

ICC
Member
# Posted: 8 Aug 2019 23:05 - Edited by: ICC
Reply 


Example of the brass adapter. I have found them at Home Depot too

https://www.amazon.com/2-pack-Brass-Fitting-Adapter-Female/dp/B079XT6TKK/ref=pd_lpo_s bs_469_t_2?_encoding=UTF8&psc=1&refRID=J3ZHJVZM9WBYBCB9J7CG

I've also seen stainless steel ones someplace--- can't remember where.

Rickkrus
Member
# Posted: 9 Aug 2019 01:13
Reply 


Bought a Shurflo 2088. Will this have enough power to lift water four feet into a pressure tank?

Steve_S
Member
# Posted: 9 Aug 2019 09:24
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A Couple of tips from Lessons Learned Dept.

Using Braided Stainless pipes made for water heaters is a GREAT solution which will solve issues IF you ever have maintenance to do. They also work really well in a Radiant Heating application to interconnect to the floor risers where being a bit flexible is a good move.

If you INCOMING water temp is too low and you feel your On-Demand Heater is working too hard OR if you want to save on propane, you can use a PRE-MIXING Valve ( thermostatic valve) which injects a small amount of the hot water created back into the cold in-flow line to warm it a touch, making it easier (less energy intensive) to get water temp up & fast without hurting pressure. This is NOT a conventional use fr such valve and not all would do it properly BUT here is a good PDF Document from Watts Industries that covers them. https://www.wattsindustries.com/images1/wif/doc/d_tmv_gb.pdf

That Tip I got from my Radiant Heating equipment supplier and BOY what a difference it makes !

creeky
Member
# Posted: 10 Aug 2019 09:15
Reply 


Nice tip Steve.

I'm using Shurflo. My biggest beef is the pre-filter.

They are hard to get sealed. The pre-filter screen thing basically lasts two years if you're lucky and then start to leak air. It is very very annoying.

I buy them two at a time now. And ditto with the plastic threads.

Brettny
Member
# Posted: 10 Aug 2019 11:59
Reply 


Buy a real filter. And housing. These small screens are almost useless. For the price you can get a small house filter housing.

ICC
Member
# Posted: 10 Aug 2019 13:55
Reply 


Have you tried drawing water through a filter that is usually used on the downstream side of a pump like a Shurflo? I have not, but given the fact that these pumps have a rather low lift (the 4048 can lift about 6 feet before the performance (GPM) falls way off, I wonder if they have enough suction ability to pull through a conventional cartridge water filter. There are better made filters similar to the one Shurflo sells for their pumps. They are also larger and use a larger area stainless steel screens like Shurflo but seem better made. You may have to check with a marine dealer as that's where I have seen them as filters for sea water bait and fish tanks.

The only purpose of the pre-pump filter is to keep particles out of the pump valve system.

Chadr
Member
# Posted: 5 Jan 2020 20:52
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I'm new here and working on a plan for going off grid soon. We are planning on one luxury, a large soaking tub. On demand propane heating is what I have been looking into but have noticed from reading through a few threads that water pressure and temperature may be issues. I will have gravity fed spring water and don't want a water tank heater. Any suggestions on where I can get things figured out?

ICC
Member
# Posted: 5 Jan 2020 23:57
Reply 


Quoting: Chadr
I will have gravity fed spring water and don't want a water tank heater.


Gravity feed has slightly better than zero PSI. If you've been reading you should have come across the figure 0.43 PSI per foot of water level "head". So if the water is 10 feet above the point of entry to the water heater that is about 4.3 PSI less friction loss in the piping. Check the specs on any on-demand heater you look at. Many won't work at that low a pressure. An RV pressure water pump might be needed.

Temperature of the incoming water: On-demand heaters should have a table or chart that will indicate different degrees of temperature rise at different rates of flow. You measure the temperature of the incoming, see how many degrees of rise you need and see what works.

How many gallons does the tub hold? My Jacuzzi holds about 120 gallons. Yes, it is a largish size. Divide the GPM of the heater into the capacity of the tub and you may decide a storage tank type is better than waiting close to an hour to fill at the rate some of the less powerful, but inexpensive, on-demand heaters can supply.

Chadr
Member
# Posted: 6 Jan 2020 08:22
Reply 


Thank you. Good info to start with.

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