Issue with AC and DC Pumps off Solar Electrical system

SystemSystem Posts: 2,511 admin
Hi:

I have had issues with my water system ever since I installed solar. Electricity is fine and all radios, tv's, lights all are working.

I had a shurflo DC pump which I bought from New England Solar in Mass. My plumber installed it but it kept coming on every other minute or so every time
we turned on the water. I have two 900 gallon water wells on a hill which flow
down hill to the place I have. I have a basement and had gravity feed so I thought
no issue, just install the Shurflo DC pump. with my Rinnai Gas water heater and should have no issues. The pump kept coming on every other minute, so my plumber suggested I get a new Jet pump instead. I called New England Solar and
they said no problem your Inverter should be able to handle it without any issues.
Sure enough the AC jet pump comes on every other minute just like the DC pump.
It loses its prime and my plumber is perplexed. So now I have a jet pump which loses it prime.

Here is what my plumber is saying (the loser!!!!!!)
The symptom that the pump is showing is similar to a tank with more pressure than the switch calls for. I checked the tank pressure yesterday because it should be 2 pounds lower than the cut-in pressure of the pump. The pressure is 18 pounds so that is not the problem – you might want to tell the next plumber that. When I turned on the power the pump was primed. You get water and pressure in the house but the pump continually turns on and off. I was going to bring in another plumber today but then saw your email last night. It’s understandable that you want the problem solved quickly and you are right to get another plumber. I’m sure he’ll be able to work it out for you. Please send me your mailing address so I can bill you for the last few hours.

Any of you SOLAR GURU'S have an idea what may be going on?
I have an Inverter and it appears to work correctly. 6 Trojan 105 batteries.
It sounds like the Plumber just does not know what he is doing. I just can not
tell what the issue is? ANY IDEAS or any SOLUTIONS WOULD BE GRATEFULLY ACCEPTED.

Charles Rowell

Comments

  • mike95490mike95490 Posts: 6,290Solar Expert ✭✭✭✭
    Re: Issue with AC and DC Pumps off Solar Electrical system

    Maybe try setting the water pressure switch to a wider setting,
    On at 18 psi, Off at 50 psi.

    Also check for a waterlogged pressure tank, and an oversized pump. 18 psi seem a bit low. Oversize pump fills the tank too fast. waterlogged tank has very little airspace to store pressure.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Issue with AC and DC Pumps off Solar Electrical system

    now i can't say i may know the answer to your problem, but i'm having difficulty knowing if the pump is feeding these tanks or is it to pressurize your home lines. if it is feeding the tanks to pressurize your home lines then that isn't good in my opinion. clarify it for these guys that have more knowledge and experience with pumps than i do.
  • System2System2 Posts: 6,290 admin
    Re: Issue with AC and DC Pumps off Solar Electrical system
    niel wrote: »
    now i can't say i may know the answer to your problem, but i'm having difficulty knowing if the pump is feeding these tanks or is it to pressurize your home lines. if it is feeding the tanks to pressurize your home lines then that isn't good in my opinion. clarify it for these guys that have more knowledge and experience with pumps than i do.

    I have a TRACE DR2412 2400 WATTS 12 Volt system.
    These TRACE INVERTERS are fully capable of powering an alterative energy household. THE DR2412 can be used for a deep well pump. It will run a correctly
    chosen submersible pump or jetpump or DC pump. I have 6 TROJAN 105 batteries
    about two years old. Everything is charging correctly. Output voltage 12O VAC
    280 Amps Input. Waveform Modified Sine Wave. So I had a DC pump coming on
    every other minute and now a AC jetpump coming on every other minute. I think
    the Plumber is the issue. Could this be a Solar Power electrical system issue?

    What I have are two wells each store 900 gallons of water. They are built up on a Spring on a hill that is about 8 feet above where my basement is. I have attached a water line to both of these two wells and the water flows down to the
    house about 800 feet or so at which point it enters to basement where a jetpump
    and tank reside. I have gravity feed from both of these wells but not enough water pressure to run up to the first floor of the house, which is why I need a shurflo pump or jetpump to pump the water up 10 feet to the first floor.

    I am trying to get the jetpump to fill up the water tank which is about 8 to 10 gallons without coming on all the time which it does every time I turn the water on. The pump and tank are brand new so I doubt the new tank is water logged.

    I just can not tell if it is the solar power system causing this issue or is it the pressure in the water tank or lack thereof... As both the DC pump (Shurflo) and the new AC Jetpump are having the same issues, it is either the Solar Power, or the other common denomimator is the Plumber. I have gotten rid of the Plumber
    and am getting another Plumber but what about the Solar. Both runs are coming
    on ok.

    I kind of think it may be because my plumber does not know how to configure a jetpump or a DC pump for that matter, but I was just wondering if anyone has had a similar issue with their solar power system as well. I have 6 trojan batteries
    and an Inverter. New England Solar felt it could easily run either pump. So I am at a loss to explain what is going on.

    Charles Rowell
  • mike95490mike95490 Posts: 6,290Solar Expert ✭✭✭✭
    Re: Issue with AC and DC Pumps off Solar Electrical system

    A 10 gallon pressure tank is WAY TOO SMALL. Those small tanks need a special pump to run them. Standard size tank is about 30 gallon, and up. I think your pump is way too big, and fills the tank too quickly. And small tank empties too fast, and pump comes back on.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CariboocootCariboocoot Posts: 17,615Banned
    Re: Issue with AC and DC Pumps off Solar Electrical system

    Get yourself a new plumber. Or better yet, become your own plumber.

    Pumps turn on because the pressure switch turns them on. They don't care what the source of power is. The power source might cause them to turn off due to insufficient power, however. So if the pump comes on, the power drops to inadequate, the pump shuts down, the power level comes back up, the cycle repeats.

    I don't think this is your problem, as one way or another the pump will eventually fill the pressure tank and then that must be drawn down below the 'on' pressure before the pump activates again, regardless of power.

    So what does the pressure gauge read? Tell me there's a pressure gauge! You should be able to get distinct results by watching the gauge and opening a tap: pressure drops below 20 psi, pump comes on. Close tap: pressure builds to 50 psi, pump turns off. If it behaves other than this (pressure settings might be different but 20 to 50 is pretty much a normal operating range) please report the results back.

    One other thing: put a tire gauge on the bladder of your pressure tank. It should be set 2 psi below the pump's 'on' pressure.
  • CariboocootCariboocoot Posts: 17,615Banned
    Re: Issue with AC and DC Pumps off Solar Electrical system
    mike90045 wrote: »
    A 10 gallon pressure tank is WAY TOO SMALL. Those small tanks need a special pump to run them. Standard size tank is about 30 gallon, and up. I think your pump is way too big, and fills the tank too quickly. And small tank empties too fast, and pump comes back on.

    I missed that tank size info. Mike is 100% correct about this. At least 20 gallon! Bigger is better for pressure tanks; reduces pump cycling.
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Issue with AC and DC Pumps off Solar Electrical system

    Your problem is most certainly in the plumbing, not the power system. As has been suggested, be your own plumber or find one who knows something other than conventional well pump systems.

    If you have gravity feed into the house, you should only need a tiny little pump to pressurize your P-tank system. I second (or treble) the note about not enough tank. Tiny tanks lead to rapid cycling. Also, pumps generally like to "push" water better than "pull" water.

    If I understand you basic system correctly (which I may not) you have gavity to the house. I would plumb the intake to the pump (making sure that line from the gravity tanks is big enough, given the distance, at least 3/4" and ideally 1 or 1 1/2 if it is a long run with lots of elbow or other restrictions). I would then run it into at least a 50 gal P-tank. (A 50 gal tank will deliver ~30 gallons of water) I would set the tank 20-40 or perhaps 30-50 psi. The extra pressure won't make any difference in the "feel" or volume of water, nor will it deliver much more water without the pump cycling, and it takes significantly more power to pump that last 10 psi.

    Tony

    PS I personally would only install a bladder tank. They never get water logged, you never introduce air to the water system. To use any other type of tank is like trying to drive the Indy in a Model A.

    PPS Your demand water heater will perform much better once you get the water pressure stabilized.

    PPPS If you have gravity feed, I think the ac jet pump is way more pump than you need, and it therefore may not be a very efficient installation. I have run single cabin systems on tiny little shurflo pressure pumps, that draw as little as ~5 amps, drawing water out of the lake, lifting it ~15' and pumping it into 20-30 psi.

    I'll stop now.
    t
  • blackswan555blackswan555 Posts: 246Solar Expert ✭✭✭✭✭
    Re: Issue with AC and DC Pumps off Solar Electrical system

    A big pressure storage tank is better all round for pump , Batts & inverter (1 long pump run as opposed to lots of little ones) But from your description I would have a look at your plumbers use and placement of non return valves (and are they the correct way round)

    Tim
  • System2System2 Posts: 6,290 admin
    Re: Issue with AC and DC Pumps off Solar Electrical system
    A big pressure storage tank is better all round for pump , Batts & inverter (1 long pump run as opposed to lots of little ones) But from your description I would have a look at your plumbers use and placement of non return valves (and are they the correct way round)

    Tim

    Appreciate the info. I am not a Plumber but what is a non return valve?

    Charles
  • CariboocootCariboocoot Posts: 17,615Banned
    Re: Issue with AC and DC Pumps off Solar Electrical system
    rowellc wrote: »
    Appreciate the info. I am not a Plumber but what is a non return valve?

    Charles

    I believe he's referring to a check valve: it allows the water to flow in one direction only. There probably aren't any on your system, as it wouldn't be strictly necessary with the Shurflo which is a positive displacement pump (has check valves built in). Otherwise there would be one between the water source and pump (usually a foot valve in a well) to keep prime on the pump (prevents water from flowing back out of the pump and into the well). Sometimes there is one between the pump and pressure tank, particularly if it is a long run.

    Which brings up another point: is it a long run from the pump to the pressure tank? If so, where is the pressure switch? It should be at the tank, not the pump. The Shurflo's (usually) built-in switch should be bypassed in such an installation.
  • BB.BB. Posts: 24,542Super Moderators admin
    Re: Issue with AC and DC Pumps off Solar Electrical system

    A check valve.

    Even if the pressure tank is too small... It sounds like there is a water leak somewhere. The pump losing prime sounds like air is getting into the system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Issue with AC and DC Pumps off Solar Electrical system

    I was going to add, check valve(s) as well as it sounds like it could be sucking air on the intake side. Tiny air leakage on the intake side will result in pumps losing the ability to pump quite easily.

    The lack of a check valve may allow the pressure in the tank to bleed "backwards" up the gravity line, reducing the pressure to the net head of the gravity. (But as I think of this, the result of this would be cycling of the pump every few seconds (or minutes) regardless of usage, so I would guess that really isn't too much of an issue).

    Tony
  • Dave AngeliniDave Angelini Posts: 2,146Solar Expert ✭✭✭✭
    Re: Issue with AC and DC Pumps off Solar Electrical system

    I am with Bill, there is a leak. Get a pressure gage $15 and tee it into the output of the pump. The 40PSI should hold for days without usage.

    Other possible problems are if the pump is very close to a water heater or worse a solar water tank. You must have a checkvalve on the shurflo output to protect it's rubber valve assembly from excessive system pressure. I have seen the 40psi output peg a 100psi gage. There are only so many times you can do this.
    "we go where power lines don't" Sierra Mountains near Mariposa CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • Texas WellmanTexas Wellman Posts: 153Solar Expert
    Re: Issue with AC and DC Pumps off Solar Electrical system

    1st off- you don't need a plumber, you need a water well man. Plumbers know about plumbing, water wells and pumps are not their speciality.

    Sounds like your tank is too small and your on/off setting is too narrow. On/Off (rapid cycling) will kill your pump and void your warranty.

    I would get a bigger tank, at least a 40 gallon equivalent bladder, or call a well guy out to look at the set-up.

    Good luck.
  • russruss Posts: 593Solar Expert
    Re: Issue with AC and DC Pumps off Solar Electrical system

    Can the pressure tank be 'water logged'? Leaked some of the air pressure in the bladder? That makes the active volume much smaller and would lead to rapid start/stops.
  • System2System2 Posts: 6,290 admin
    Re: Issue with AC and DC Pumps off Solar Electrical system

    Well, I have this camp and have not been able to take a shower at the camp for two summers. I just wanted to thank all of you for your advice on this particular matter. First of all, all of you who recommended getting a new plumber were absoulutely correct. I just learned a bunch of things the former plumber did wrong.
    Getting the right plumber versus the wrong plumber can make all the difference in the world believe me.

    The first thing the new plumber caught was the fact that I had no check valve. In case any of you don't know what that is, it stops the water that your pump has drawn from your well or submersible well from going back down into the well. I have 5 PSI water pressure gravity feed. The tank has 18 PSI minimum and 40 PSI
    at the high end. The former plumber had installed a Shurflo DC pump with a 40 gallon tank. Then he had me install a jet pump with a smaller tank. In both cases
    the dc pump and jetpump kept coming back on recycling if you will. Once the new plumber installed the check valve it stopped the recycling. Now the pressure is still going down and we have some sort of slow leak even when the water is turned off. The former plumber also installed the wrong size diameter lines. We needed 3/4 on the lines and we had 1/4 inch lines.

    So, what did I gather from all of this. Get the right plumber, because if you get the wrong plumber you might not be able to use the shower in your Solar powered camp for two years because you were convinced that it was something you did wrong and not the plumber whom you rely on to know such things. Just FYI it was not a Solar Power issue but a plumber(not understanding Solar equipment) or plumbing for that matter. Suffice to say I enjoyed my shower for the first time...

    Charles Rowell
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Issue with AC and DC Pumps off Solar Electrical system

    Glad you fixed it!

    1/4" water line? Who in the world would design and build such a system? Even in an RV water lines are routinely 1/2" minimum!

    To find a leak, you can install a tee, valve or plug off all appliances that would be effected by high pressure, then pressurize the entire system with high pressure air,,,~100ps, watch the gauge drop, then listen for the hiss.

    Tony
  • solar_davesolar_dave Posts: 2,261Solar Expert ✭✭✭
    Re: Issue with AC and DC Pumps off Solar Electrical system
    icarus wrote: »
    Glad you fixed it!

    1/4" water line? Who in the world would design and build such a system? Even in an RV water lines are routinely 1/2" minimum!

    To find a leak, you can install a tee, valve or plug off all appliances that would be effected by high pressure, then pressurize the entire system with high pressure air,,,~100ps, watch the gauge drop, then listen for the hiss.

    Tony

    I have used the air pressure trick before, and to isolated is even further a little dish-soap and water brushed on the joints while pressurized will make it stick out like a sore thumb. It helped me find a really slow leak.
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Issue with AC and DC Pumps off Solar Electrical system
    solar_dave wrote: »
    I have used the air pressure trick before, and to isolated is even further a little dish-soap and water brushed on the joints while pressurized will make it stick out like a sore thumb. It helped me find a really slow leak.


    That is the same trick for finding gas line leaks. Gas lines are pressurized to 30 psi for 15 minutes which is a much better test than just looking for leaks with a soap solution, as regulated gas pressure is ~1/2 psi. If it doesn't leak down with 30 psi, it sure won't leak with 1/2 psi.

    Water plumbing I would pressurize to 100psi, being careful not to put that kind of pressure against certain valves like toilet fills, or dish washer or washing machine controls.

    Tony
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