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Rickkrus
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# Posted: 20 Mar 2017 04:04pm
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I am a bit confused on the size pressure tank to use. I'm planning on a 300 gallon storage tank in the cabin. Then a Shurflo 4008-101-E65 pump to a Waterworker HT-14B vertical pressure tank. Will the pressure tank be ok or too big for what I am planning?
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Just
Member
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# Posted: 20 Mar 2017 04:18pm
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You could go a bit smaller if space is a issue, but that should work well . The pump will work without a tank but, a bit better with one..
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bldginsp
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# Posted: 20 Mar 2017 06:39pm
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You can put in as large, or as small a pressure tank as you want to, it's just a matter of short term or long term economy.
A small pressure tank is less expensive but will cause the pump to come on and off more frequently, shortening the life of the pump. Pay less for the tank now, more for pumps later.
A large tank costs more at the outset but causes the pump to come on less frequently, extending pump life. More cost at the outset, less down the road.
Pump life is a function of number of times it is switched on and off, generally. That's the hardest thing on the pump. From what I hear the Sureflows don't have the best reputation for longevity (but never used one myself) so you have to ask yourself how often you want to replace the thing.
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Al Burton
Member
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# Posted: 20 Mar 2017 09:21pm
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Be aware that if you are using an instant hot water heater like an eccotemp the change in flowrate with a small expansion tank will cause fluctuating water temps. Ask me how I know this! I am looking at upsizing my pressure tank because it is always a challenge while showering when the temp goes from cool to scalding.
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Rickkrus
Member
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# Posted: 21 Mar 2017 12:55am
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What's a small tank? I see some that are only 2-4 gallons in size. Is 14 big enough to prevent this?
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bldginsp
Member
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# Posted: 21 Mar 2017 08:57am - Edited by: bldginsp
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Not real experienced with tanks, but the basic issue is cycling. If the tank can deliver enough water for one shower before cycling, it should only cycle once during the shower. Which means you only get scalded once instead of four times. Could be that larger tanks reduce the effect of each cycling pressure variation just due to size. I'd call or email a tech support and see what they say. If you do, let us know.
There is something called a CSV, cycle stop valve, that is supposed to cure the problem, but I don't understand how. Here's one link-
http://inspectapedia.com/water/Short_Cycle_Stop_Valves.php
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Al Burton
Member
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# Posted: 21 Mar 2017 02:10pm
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True mine is small at maybe 3-4 gallons. That CSV valve looks like it might be the ticket for sure. I will have to look into that. Thanks bldginsp! I was thinking of a regulator on the inlet of the heater but will check this out. I store 1000l (250G) of water in my utility building that I keep heated all winter. Another problem I ran into is that when I am gone I set the temp down to 38f or so. When I get to the cabin the water is now 38 and I have to crank up the eccotemp. As the week progresses the temp of the water tank goes up and the temp out of the heater goes up accordingly. More adjusting. The things we don't anticipate are half the fun I guess!
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Just
Member
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# Posted: 21 Mar 2017 02:31pm
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All that velve does is add some air to your tank it will not work with a blater tank like you have pictured. that is why they invented blater tanks so you never get too much water in the tank. the best way to fix your problem would be to get a larger pump and keep that tank.I think they make a 3 gal. per min. pump should work..I have 6 rural
pumps with tanks working every day
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Al Burton
Member
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# Posted: 21 Mar 2017 03:04pm
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Just; the issue I have while showering as follows. When I start the water flowing the pump is off and at max pressure and flow. As the shower goes on the pressure and flow drop until the pump kicks back on. 30 seconds or so later the pump shuts off again as it hits the high cutoff setting on the pump switch. This cycle of on/off continues. Because I am using a demand water heater, as the flow rate through the heater decreases the temp of the water out of the heater increases and vice versa. In this case we go from lukewarm to scalding hot and back again. I am unclear how a bigger pump would solve this. I was thinking either a bigger pressure tank so the pump won't cycle during a shower although the flow would still change to some degree. The other alternative would be a regulator at the heater inlet or going to a smaller pump that would not cycle at all. Thoughts? sorry if I hijacked the thread.
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Just
Member
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# Posted: 21 Mar 2017 03:58pm - Edited by: Just
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Sorry Al I was refering to Rickkrus's problem I see buy your pic you have a much bigger pump . not sure what kind of pressure tank you have but you may need to add some air to your tank or adjust your pressure switch so it kicks on at a little higher pressure.The adjusting screws are inside the power box on the pump There are 2 screws follow the instructions inside the cover.You will want to raise the cut in pressure and leave the cutout the same ..It should cut in about 35 lb and turn off at 40lb that will solve your hot cold problem.
Rickkrus sure flow pumps have factory set pressure switches not adjustable to my knowledge.
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NorthRick
Member
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# Posted: 21 Mar 2017 04:07pm
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Al, you might try installing an anti-scalding valve at the shower. They are supposed to automatically adjust the incoming hot and cold water to keep the temperature at the shower head constant.
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Rickkrus
Member
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# Posted: 21 Mar 2017 09:30pm
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Don't have to use a Shurflo. What brands are better?
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Just
Member
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# Posted: 21 Mar 2017 10:18pm
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Are you on or off grid ?? Al Burtons pump is a 110 volt pump and pumps 8 gal per min ..surflow makes a large 3 gal per min 12 volt pump not sure how much the water heater needs to run properly.
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Rickkrus
Member
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# Posted: 21 Mar 2017 11:53pm
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Off grid solar and propane. That shurflo is 3 gallons a minute with preset 55 psi.
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Rickkrus
Member
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# Posted: 22 Mar 2017 12:02am - Edited by: Rickkrus
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Ecotemp 10 delivers 2.6 g/m and ecotemp 12 is 3.6 g/m both operating at 30-80 psi.
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Just
Member
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# Posted: 22 Mar 2017 08:57am
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So you have it all rite,all you need now is a valve were the supply line leaves the tank so you can restrict the flow to balance the hot and cold supply,should work ..the valve will allow you to control the water exiting the tank to a more constant flow..
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