Considering Adding a Pressure Pump (Hidroneumatico) to Your Gravity Feed System?

About every 6 months, someone new pops onto Mexican expat construction and home repair forums and asks about the in’s-and-out’s of improving their household water pressure by adding a hidropneumatico (pressure-pump) that includes a bladder & tank system.

There are a number of issues and alternate problems that need to be considered first before choosing to install a pressure pump system on an existing gravity feed water system. If you rule out other likely problems, and still need/want even higher pressure, then there are also issues to consider about what type of system to buy, how to protect it from the weather and sun, and who to hire to install it.

Common misconceptions and frequent advice that is off the mark
Some expats advise that the person should get a bigger tinaco:
~ Getting a larger tinaco usually does little to affect pressure, unless your tinco re-fills only slowly. Bigger tinacos fill much more slowly, actually giving noticeably lower pressure in gravity feed systems.
~ Raising the height of the tinaco does increase pressure in a gravity-fed system, so raising your tinaco even 4-5 feet may make all the difference.

Some expats advise installing large pipes (1½ inch-3 inch) in the plumbing between the tinaco and house.
~ If your tinaco is only 5 to 9 feet higher than your faucet or shower head, increasing the size of the “down-pipe” will not increase pressure noticably (unless you have really small ID plumbing.) 3/4 inch ID plumbing is usually sufficient in most instances.

Is the “Pressure Problem” really due to low pressure, or might there be other issues?
~ Are you sure that the problem is the pressure? e.g. Some types of shower heads work much better than others in gravity feed systems. As seen in the next 4 points, reduced flow can be the actual cause of seeming pressure problems. e.g. Do you have low flow and low pressure at all points in the system, or in just selected areas? If you answered that the pressure is too low at ALL points in the system, then you really might need to raise the tinaco or buy a hidropneumatico.

~ Does your “new” system have vent pipes on every high point in the system’s sections? If you don’t have vent pipes at strategic points, the systems often get small/partial cavitations at high points – where a little trapped air greatly reduces flow. There are some good tricks for removing these cavitations/air-bubbles if you want to send me a PM.

~ Have you definitively ruled-out physical blockages? I have seen 5 different “new” systems where the workers got small rocks, sand, bits of concrete, and other dreck in the new plumbing – partially blocking the little valves beneath sinks & toilers, or blocking the flexible connectors, etc etc etc and lowering flow and pressure.

~ If there were ever runs of white PVC pipe running in sun-exposed areas, the pipes are almost guaranteed to grow algae inside, and then bits of algae break loose and partially plug narrow spots in the plumbing. This algae lasts for years.

~ Physical blockages must be physically removed by either opening up key joints & connections & fixtures, or blast the gunk out with a high pressure flow of water, or suck out the gunk with strong vacuums – like from creative use of a rigid-walled garden hose.

After Resolving all other likely problems/issues: What equipment should you consider:
~ Pressure pump systems that cost less than about $2,500 – $2,700 pesos generally use lower quality components and tend to fail within 1 – 3 years.
~ Even if you buy a better quality hidroneumatico system (spending more than $3,000 pesos on the pump and bladder system), like an Evans brand system, many of these models must be protected from the sun and weather, because their plastic parts break down in our tropical sun.

Potential Issues Unique to Retrofitting a Gravity-Fed Water System with a Pressure Pump:
~ Most Yucatecan plumbing jobs are done by workers who do not understand the materials or how to install them, or they take hidden short-cuts, which means that even Yuco-PVC systems with glued joints often do not tolerate pressures above 20 – 25 psi. I’ve had to repair 2 different systems where the workers made home-made unions by trying to glue a section of slightly larger pipe over the 2 neighboring pipes as a funky connector that leaks under the pressure of their new hidropneumatico. It’s really a challenge when the leak is hidden under a walkway or floor, and the water just flows down into the ground unseen.

How to Select a Plumber to Install the New Pressure Pump / Hidroneumatico System:
~ Hire only a well-qualified plumber who is well experienced and consistently successful with retro-fitting hidroneumaticos onto Yucatecan systems.
~ If your prospective “plumber” plans to install the new hidroneumatico without unions, find a new plumber.
~ If your prospective “plumber” plans to to use cheap parts – like a less expensive check valve – find a new plumber.
~ Ask your prospective “plumber” what range of working pressures he intends to use, and also ask how he plans to adjust the upper and lower pump pressure settings, and the bladder pressure, and what pressures he likes. If he looks at you blankly, or hesitates, or waffles or hand-waves about how that’s all preset at the factory, then consider finding a different plumber.
~ Figure out whether your prospective “plumber” has considered and ruled-out all the potential flow-issues described above. If he has not checked-out the 5 points I described above, it may be time to interview a different plumber.

Your final system settings should have a working range of about 5 psi, with the air bladder pressure set either at the low-pressure pump-start pressure or 3 psi below that value. Pressures set higher than 20 – 25 psi tends to cause problems with most Yucatecan plumbing systems. e.g. The D ring seals and coupling designs in flexible connections used here to couple faucets and toilets to the PVC pipes are just not designed to handle pressures higher than 20-25 psi, not to mention the potential for hidden leaks inside walls or under floors.

Hope you get all the pressure you want and enjoy years of strong showers and brisk flows.

* * * *
Feel free to copy while giving proper attribution: YucaLandia/Surviving Yucatan.
© Steven M. Fry

Read on, MacDuff.

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21 Responses to Considering Adding a Pressure Pump (Hidroneumatico) to Your Gravity Feed System?

  1. Pingback: Considering Adding a Pressure Pump (Hidroneumatico) to Your Gravity Feed System? | Surviving Yucatan

  2. Eric Chaffee says:

    It looks like the article is missing.

    ~eric.

  3. Eric Chaffee says:

    But once I posted my comment, it magically appeared! (Not sure what the issue is.)

    ~eric.

  4. Tzatzil says:

    Hi.
    I am trying to find out what is more energy and water efficient (I don not live in Yucatán, but in Oaxaca) and your blog came up. I am building a new house (al the pluming has been installed) but we are not sure between a ROWA pressurizer and an hidroneumático.
    The ROWA goes on and off every time you open the water and this does not seem efficient to me, but my husband is convinced that the amperage required to do so is less than what is used by the hidroneumatico.
    I see that your page is all about adapting in Yucatán/México, more than about plumbing but you seem to have a rather ample knowledge on the subject, so your insight would be helpful.
    Thank’s
    Tzatzil

    • yucalandia says:

      Hi Tzatzil,
      Good question.

      If the ROWA is a small unit (100 Watts), then it can be more efficient.

      Since typical AC appliance motors use at least 40% more current when they start up, it is cheaper to run an AC motor longer to pressurize the tank for one longer cycle than it is to start it up several times in several shorter cycles. Since the ROWA presssurizer starts up every time the pressure drops, it goes though the low low efficiency startup cycle 2X to 4X more often than a hidropneumatico/pressure-tank system.

      Why AC motors use 40% – 70% more power when starting: Whenever the phase of the load (armature) is out of phase with the AC line frequency, the motor consumes more power/current trying to get the armature up to speed to match the line frequency. When the motor first starts, the armature is turning only slowly – far out of phase = using a lot more current. As the motor starts spinning closer to it’s operating speed, the motor draws much less current, and at the full operating speed, it draws even less.

      A pressure tank / hidropneumatico system allows the pump motor time to come up to full speed, and then runs the motor at its highest efficiency while pressurizing the tank – minimizing the expensive start-up period.

      This analysis assumes that the 2 motors are approximately the same size.

      Since some of the ROWA pressurizers use only 100Watts, they only draw less than 1 amp when running. If the ROWA draws 40% more power during startup – it would draw 140 Watts during starting… A typical hidropneumatico has a 1/4 horse motor, which uses about 3.2 amps => 350 watts….

      So, if you choose a smaller ROWA, it will use less power than the hidropneumatico, but the small ROWA only makes a maximum of 6 gal per minute, which means you might not want to flush a toilet while taking a shower. Since it is a small low-power pump – Brasilian made – based on a Swedish design – it does not pump water that high…

      Did your hubby look at it’s specifications? See: http://www.imagemrio.com.br/manuais/Manual_da_Mini_Bomba_Pressurizadora_de_agua_TP40_Komeco_40W_-_110V.pdf page 15. At 8 meters of head pressure, the flow drops to just 5 lpm = 1.3 gal per min = a pretty weak shower…

      If you only have a 1 story house, the ROWA should work OK, if you take showers without watering the yard, flushing the toilet, etc. If you have a 2 story house, with the ROWA on the first floor – far from the bathroom, you may find shower pressure less than exciting.

      Looks cool though….

      Make sense?
      steve

  5. Tzatzil says:

    Thank’s Steve. We will take your comments in to consideration.
    Saludos, from Oaxaca.
    Tzatzil

  6. Missy says:

    Hi Steve,
    I hope you don’t mind me dropping in here to ask some questions about water pressure systems! We had one of those big 100-liter orange pump/pressure systems from Niplito that got louder and louder as the years wore on, and after about 2 months of abrupt and frequent short-cycling, it finally kicked the bucket yesterday after 4 impressive years. We need to replace it ASAP, as we don’t have a gravity-fed system as a backup and are currently roughing it without running water.

    Some background: our previous system was basically pulling water (along with all kinds of debris, I’m sure) straight up from the ground, without any filtration, which I assume contributed to the increasingly loud grinding sound and eventual bucket-kicking of the whole thing (we were very new at this when we started out here, and we let our contractor handle the whole thing while we were still out of the country). This time around, we’d like to do this properly, and welcome any advice you have for our particular set-up (no city water, no tinaco, a two-story house with 2 full baths and a washing machine, I’m not sure of the width of the PVC piping, but I could find out if that’s useful information); plus any advice you might have for finding a plumber “well experienced and consistently successful with retro-fitting hidroneumaticos onto Yucatecan systems.” Have you ever worked with anyone from Impulsora Hidraulica? They were recommended by someone at Home Depot, and it seemed like a good suggestion, since they seem to offer maintenance service also (our “service man” for our previous system was… well, let’s just say he doesn’t match your description above for what to look for in a plumber.) Any suggestions are very welcome, and I’m very grateful for all of your very helpful information here!

    • yucalandia says:

      HI Missy,
      Other than Jan, (a fellow from Belgium), we still have not found a really good plumber yet. Jan charges more than the local guys, and I am not sure if he is still doing plumbing (as we have not seen him in a year). I can send you his email if you are interested.

      When installing the new unit, inspect your well, to see that is clean, and that the intake tube for your water system is properly positioned. The tube should be pulling water from a point not next to the bottom of the well. Do you get debris or sediment in your toilets or tubs when running water? If there is no debris or sediment accumulating in the showers or toilet tanks, then the water is likely not causing the hydropneumatico.

      I have not worked with Impulsora Hidraulica. When you select your new hydropneumatico, be sure to get one with a large enough motor to lift the water out of the well. As you inspect the well, measure the height that the pump must lift the water from the water level in the well up to the pump. The new pump should be rated to lift water at a decent flow rate (3 gal per minute minimum) at your ____ feet of head, If your uptake tubing between the pump and the well has a lot of elbows, then add 3 feet of additional head to your measured head, to select a large enough pump.
      All the best,
      steve

  7. Missy says:

    Many thanks Steve! This is really helpful. We found a fiberglass tank at Rivas that suits our needs and will be rust-free, and now we’re just trying to figure out if we want to get the submersible motor, which costs more but will be quieter? Or attach an above-ground motor. Any thoughts on that end? Thank you again for your time. -M

  8. Lucio de Souza says:

    I love your work, I am now in Brazil and trying to improve the water pressure in my house, after read your work, I question my self now if I really wants to pressurize the gravity fed system. Here they don’t have the same standards for plumbing workers as in USA, anybody can be a plumber.
    It scars me, because I did not had the control who did the plumbing when the house was build. As a Brazilian I know that they did a lot short cuts, and did not use the PVC glue the way it suppose.
    I will follow your steps to try to find where is the cause to loose the pressure, and my last thing will be to raise the container to increase pressure or start over with the plumbing, witch economic unreliable task. It is very sad when you build a new house and have the same problem as the last century houses, that’s why the call us third World country,growing economy without any standards, disaster at the end.

    • yucalandia says:

      Hi Lucio,
      Your insights are exactly what we have here in Mexico. Anyone can do plumbing with no training. They use the wrong parts, they glue things badly, they solder them badly, and then they bury them in the wall or in the floor.

      With our similar plumbing, I have found that on some friend’s houses, we can use a hydropneumatico, but only at a very low pressure of 16 psi – 20 psi. If you install the hydropneumatico, then do a little test. Let the hydropneumatico run up to its highest pressure setting, where the pump shuts off (say 22 psi). Then USE NO WATER for the next 30 minutes or 1 hour – checking the gauge pressure every 15 minutes. Your water system should hold that “22 psi” for 30 minutes, 1 hour, 2 hours….

      If the pressure drops during the test, then you either have a leak in the house somewhere, or… the check valve between the hydropneumatico and the tinaco (water supply tank) is leaking… If the pressure stays constant at your highest pump setting, (“22 psi”), then your system can take the pressure – and is good.
      steve

  9. Alfredo says:

    Hey! I’m at work browsing your blog from my new iphone! Just wanted to say I love reading through your blog and look forward to all your posts! Keep up the excellent work!

  10. Jack Wall says:

    Building a house in Cansahcab. Water flow from the town supply is horribly slow, barely a trickle. I am afraid that unless I have several tinacos, we will run out of water and I reeeeeeeaaalllllly like water pressure so I am trying to avoid the pitfalls before we get to that point. I will most likely install the system myself, if that’s possible. Never done it before, in Mexico. I will be there Nov. 16 to begin overseeing the work which begins tomorrow.
    considering installing a windmill for the water supply and the pool. looking to find out which way to go.
    I would like to have a more indepth discussion when you have time and maybe even FTF if you are in Merida or thereabouts.
    Thanks

    • yucalandia says:

      Hi Jack,
      Barely a trickle, eh? Any chance that there is more flow in the middle of the night? If it is terrible flow all hours, is it possible that they kinked your line? Same crummy flow at the “upstream” neighbors at all hours?

      If there is one time of the day with a bit more flow, then you could use a pump to gently suck water during those hours, to fill a tinaco.?
      steve

      or are you thinking well?

  11. Boxito says:

    Hi, I have 2 hidropneumatic pumps here in Merida and one in uaymitun and i highly rececomend Valto tecnlogies for equipment and instalacion, they are professional people and very helpful. They are located a couple of blocks from parque aleman on aleman avenue..

  12. Joe vizzi says:

    Does the amount of water in a storage tank affect the pressure in a gravity fed system?

    • yucalandia says:

      Hi Joe,
      Yes, higher water levels in the roof-top storage tanks increase the pressure a little.

      The increase in height inside a typical tinaco changes by about 2 feet when mostly empty to full. If you have a 1 story house, then the roof is only about 6 feet above the level of the faucets (for newer construction), and the tinacos are often on a 2 ft platform – which gives you 8 feet of head pressure. If the water level in tinaco is 2 feet higher (from being fairly full), then you gain an extra 25% more pressure.

      If you have a 2 story house, then the tinaco’s base is likely 18 feet above the first floor faucets (but still only 8 feet above the 2’nd floor bathrooms). In that case the additional gain of 2 feet of head pressure (for a full tinaco) only adds 10% more pressure at the first floor faucets.

      If you have pressure problems in a gravity fed system, check for white PVC tubes that are exposed to sunlight – like on the roof. Since gravity fed systems have a breather pipe that is open to the air, the water system sucks in air every time you run the water – and air contains algae spores.

      The white PVC pipes have relatively thin walls that allow sunlight to illuminate the inside of the pipes – making a nice algae garden. The growing green/grey/or blackish algae slowly plugs the pipes – and worse yet, when a little chunk/mat of algae breaks loose – it can partially block elbows, valves, faucets, shower heads etc. If this has happened, I have found it takes a pressure washer to blow the little algae blockages out of the lines. If you just hit the system with chlorine, it kills the algae, but the dead algae mats then flow through the system to block even more spots.

      Our solution: Kill the algae with bleach (1 cup per 275 gal tinaco) – mix the bleach in the tank – wait 20 minutes run each faucet in the house until you smell bleach. Let the dilute bleach soak in the pipes at least 2 hours. Flush the system – hopefully opening a big oepn holed faucet connected to a big pipe – to allow the dead algae mats to flow out without blocking sink aerators or shower heads.

      If this does not cure the low pressure problem at a faucet, you may have to use a pressure washer to blow out the blockage… We have also found sand and sediment partially clogging lines if you have a small plumbing leak in a line that runs through a floor – underneath the concrete. … ???
      Your thoughts?
      steve

  13. Rick says:

    What it really makes a diference is the height of storage tank.

  14. Elizabeth Robertson says:

    Hi. We live in Ixtlan del Rio, Nayarit. We just rented a house that was in bad shape, but we have been fixing it up. We have a tinaco and fairly good water pressure everywhere except the upstairs hot water for the shower and the hot water in the kitchen. You had mentioned about air bubbles in your blog. Would that cause those two faucets to be slow letting out water? We would be fine with the low water pressure, but my dishwasher does not fill up quickly enough before the timer sets it going on with the wash cycle. I think it is because of the poor hot water pressure in the kitchen. Can you think of an inexpensive and easy fix for these problems? Thank you.

    • yucalandia says:

      Hi Elizabeth,
      I have seen pebbles in Mexican water lines, I have seen sand in Mexican water lines, I have seen little pieces of gravel in Mexican water lines, and I have seen little pieces of concrete in Mexican water lines.

      It is possible that you have air bubbles (cavitations) in the water system, due to not enough air vents, but it is also possible that you have some obstructions. If you have white PVC pipes running across the roof – or down a wall – that are exposed to direct sunlight – you may also have an algae garden inside the pipes.

      We have successfully blown out sand, gravel, pebbles, and algae using a pressure washer. Open one part of the supply side of the water circuit where you still have good flow/good pressure – upstream of the suspected blockage to the dishwasher – and then remove the water line to the dishwasher and route it into a light colored bucket. Turn on the pressure washer and carefully/gradually direct the high pressure stream into your pipe to try to force out the blockage. You really may not want to directly connect the pressure washer to the pipe – because you don’t want the high high pressure to create leaks in your likely-weak Mexican plumbing (like inside a wall or under a floor). In our cases, by gently increasing the pressure – a plug of sand, piece of gravel, pebble, concrete, or a bunch of rubbery algae blew out into the bucket. It’s messy where you make the intentionally leaky connection between the pressure washer and your plumbing – but it works…

      If you have an air bubble, this method might also work – but usually with an air bubble, just disconnecting/removing small fittings and allowing a brisk flow of water to flow for a minute or 2 minutes is enough to push out the “burps” and remove the bubbles. If the air bubble is in the second floor’s upstairs plumbing, you can fill a long garden hose with water – don’t let the water escape from the hose – very tightly connect the hose to your low-flowing outlet – route the still-full hose down to the ground level – and then open the hose – where the siphon action of the hose .. sucks out the air bubble – leaving you with no cavitation(s) – and good flow – until the next air bubble gets sucked into the system (like from low water levels in the tinaco). If it continues to happen, you may have to either install a new vent line, or just run new pipes.

      Best of luck,
      steve

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