Water Tank Air Charge FAQs

Water Pump Turns On Immediately - No Air in Pressure Tank?

Why does my well pump turn on the second I open any water tap?

My well pump cuts in as so as i turn a tap on. Why? On 2018-02-19 by Gerard

by (mod) - no air charge = waterlogged pressure tank so pump turns on immediately

Probably your water pressure tank is waterlogged, that is, it has lost its air charge.

See the repair procedure

at WATER TANK AIR, HOW TO ADD

Why does our Water Pressure Booster Pump Turn On Immediately when we Run Water?

We have a Davey HS18-30 booster pump with a small water pressure tank (2 gal?). The pump was in the house when we moved in, so I assume it was installed in 2004 when the house was built.

When running "normally" it comes on almost immediately when the water (any faucet) is opened, runs the entire time water is being drawn, then shuts off ~1sec after the faucet is closed. Is this the expected behavior?

However, on occasion the pump will run continuously while no water is being drawn. There are no leaks (running toilets, etc) in the system, but the pump will not shut off until we kill power to the pump and it will immediately start to run again when power is supplied.

We turn the pump off as soon as we realize this occurring but we have sometimes come home and find the pump has been running for hours (it's very hot and has heated the water in the pipes).

Eventually it returns to the "normal" operation described above. I'd like to figure out why this is occurring and if it is repairable or if this has potentially damaged the pump enough to warrant a replacement. On 2020-11-12 by Cameron

by danjoefriedman (mod) - For a Tankless Pressure Pump that's normal

Cameron

Some water pressure or booster pumps use an internal pressure sensor and are intended to turn on immediately when you open a tap.

Here's the DAVEY HS-SERIES DYNAFLO PUMP MANUAL [PDF] (at the Davey Water Website) - local copy saved as Davey-HS-Pump-Manual.pdf

For other readers in Australia or New Zealand, if you have a Davey HP.T or HS/T series pump, see this

DAVEY HP/T-HS/T WATER PRESSURE SYSTEM PUMP MANUAL [PDF] (at a New Zealand Pump Dealer Website) - local copy saved as Davey-HP-Pump-Manual.pdf

You'll see that Davey as well as municipal water system regulations all recommend an isolation tank between the main water supply and the pump. That's probably the purpose of the small water pressure tank you cite.

But the instructions say nothing about the pressure tank air pre-charge.

I think that it is normal for this pump to turn on immediately when you open a tap, as the little water tank you mention is an isolation tank, not a typical water pressure tank.

Another example of a water pressure pump that does not use a separate pressure tank and that runs immediately and continuously when you're using water is the GRUNDFOS SCALA 2 PUMP

How to Drain a Water Pressure Tank that has No Drain Valve

How do I drain the Water Tank if there's No Tank Drain?

How can I let water out of a water tank that has no drain? On 2016-06-23 by walt

by (mod) - working on water tanks & pipes when there is no shutoff and no water tank drain

The water pressure tank will have piping connected to it.

That piping either goes to a tank tee that includes a drain valve, or you can install one by turning off the pump, draining pressure from the system, then cutting the pipe.

In the worst case I'd find the lowest and/or nearest outdoor faucet or hose bibb, hook up a pony pump using a washing machine hose to connect the pump to the faucet, then with the pump electrical power turned OFF, I'd open one or more indoor faucets to let air into the system, the run the pump to draw all of the water out of the system.

If necessary there are freeze fittings or other devices that let us work on water pipes without draining the system. Let me know if you need help finding one of these.

See water tank draining step by step details found at WATER TANK DRAIN VALVE 

More suggestions that might help you are at ADD AIR to a BURIED WATER PRESSURE TANK - ideas on how

Can't Add Air to the Water Pressure Tank Q&A

Do I have to drain my water tank prior to adding air?

Do I have to drain my tank prior to adding air? My air pres. The tank is now at 26PSI and it is suggested I increase to 38 PSI. Oct 6, 2014) George

Reply:

No George, but 38 psi sounds a bit high unless the pump control CUT-IN pressure is 40 psi - which would be the case if your pump pressure control switch is intended to turn ON at 40 psi and OFF at 60 psi.

 

I can't get air into my water pressure tanks

I have two hydro-pneumatic galvanized tanks that are over 50 years old, connected to a well for irrigation.

I've recently replaced the well pump, and the system worked well (cycling from 40 to 60 psi) for a couple of months.

However, now, after mild use this spring checking the stations, I can no longer manually air-charge the system to the recommended 20 psi (before I could but it took a very long time), and the pump will not cycle on although the tank pressure = 0!

Should I just change out the pressure switch or do I need to replace the tanks? Any suggestions greatly appreciated. On 2022-05-06 by Marvin

First steps by InspectApedia Com Moderator

@Marvin,

Let's base our decision on objective facts: we need to understand "why" you can't correct the air charge in your pressure tanks: is there a bad air valve such as a jammed valve pin assembly or dirt or crud in the air valve inlet, or might your tanks have stuck air or water tank bladder, (if your pressure tanks use an internal bladder), or something else?

by Marvin

@InspectApedia Com Moderator, These are hydropneumatic tanks that don't have bladders to get stuck.

by InspectApedia Com Moderator - check the Schrader valve air inlet for damage or clogging

@Marvin,

Still I'd look for a blockage at the air inlet. After all, if by "can't air-charge the system" you mean you cannot introduce air into the tank and if you've already tried replacing the Schrader valve stem, then there must be a rust or crud blockage.

by Marvin - Air inlet valve not blocked

@InspectApedia Com Moderator, Thanks for your replies!

I replaced the Schrader valve core, and then probed its internal plumbing for several feet with a wire.

I didn't feel any obstruction.

Unfortunately, I'm still not able to pressurize the tank after 5+ minutes pumping with electric auto tire pump. Not even a little, although air seems to be readily blowing through the tank's drain faucet when I open it.

by InspectApedia Com Moderator - check for a debris clogged pressure gauge

@Marvin,

Is it possible that in fact you are indeed adding air to the tank but the pressure gauge itself is clogged and not registering?

by Marvin

@InspectApedia Com Moderator, Its possible. I'll replace the gauge next. Thanks for the suggestion.

by Marvin - I was able to pump air into the tanks

@InspectApedia Com Moderator,

Today my well people found that the brand-new pump is cycling on/off too quickly (Q 45 sec), causing the capacitors in the new control box to over heat and shut down the high capacity pump.

I was able to air-charge both tanks today to the recommended 20psi, which improved the cycle time but only to about 1-1/2 minutes, with tank refill taking another minute.

The pump contractor thinks that the tanks need to be replaced with 120gal bladder models for $3K apiece. (BTW turns out my tanks were placed in service in 1959!). Does this make sense?

I forgot to mention, that even after the improvement in cycle time following air charging, the pump still shuts down before getting through all six irrigation stations.

by InspectApedia Com Moderator - check the air pre-charge pressure to be sure it's 2 psi below the pump CUT-IN

@Marvin,

The pump may be shutting down because it's overheating or because there is a pump protection device that is protecting it from damage when it starts pumping air rather than water.

But also I wanted to ask how you came up with the 20 psi air pre-charge. The water tank air pre-charge needs to be 2 PSI below the pump cut in pressure setting.

Air Charge in Pressure Tank Seems to Get Lost & Pump Short Cycles

Water pressure tank won't hold its air charge

I add air to the pressure tank but it looses the air after a while is the tank bad On 2016-07-30 by Anonymous

by (mod) - why adding air to the pressure tank may be needed

Anon it depends on how long it takes for the tank to lose its air charge, and how much water is being used in that interval.

If your system has a tank that uses an internal bladder you should never need to add air - so that'd be a bad tank;

If your water tank does not use an internal bladder it may need a replacement Air Volume Control or AVC device.

My water tank system pumps up to 50 psi and then bleeds down to 45 psi in half an hour.

My system pumps up to 50psi and then bleeds down to 45psi in a matter of half an hour.

I looked for leaks and only found that the air valve on the storage tank show a small leak using soapy water.

Any clues? Where can I find a new air valve for my tank?

The storage tank should be empty when checking the charge. The charge should be 28psi. On 2017-04-08 by Dave

Reply by (mod) - Recommended diagnostic steps

Dave:

Before replacing any parts in what we call the "shotgun" approach, let's see if we can figure out what's going on. That will improve the chances of a successful repair.

1. Are we sure that no water is running in the building?
   
   For example a running toilet will slowly use water - a condition that might show up at the water tank pressure gauge.
   
   Try closing off the main water valve into your building. That should, if the valve is reliable, rule out any hidden leaks or missed water consumption.
2. If you think the leak is at the air valve on the water tank, first try tightening the screw cap on the valve - that should stop the leak completely, if only as a temporary repair.
   
   You can replace the Schrader valve stem core in the valve if necessary. It's a standard part commonly available even at auto parts supply stores.
3. Does the pressure drop STOP once the gauge says 45 psi?
   
   Could the gauge be debris clogged?
   
   Air or pressure gauges used on water pressure tanks are standard and easily replaced. Any plumbing supplier has them.
   
   Air valves - used for adding air to a tank, use a standard internal valve stem or core, but the valve itself may be customized to fit the tank depending on the tank type and model.
   
   A steel bladderless pressure tank may use a conventional air valve (Schrader valve) that's available at any plumbing supplier.
   
   A water pressure tank using an internal bladder may use a special rubber-based air valve that is supplied by the tank manufacturer and that might be replaceable
4. If none of the above steps stops the pressure drop I suspect there's a leaky foot valve or check valve or (less likely) an air leak right at the pump itself that is allowing water to run back into the well or leak underground. Usually a plumber or well repair company will at that point either pressure test the well lines and pump or pull the well piping to first check or replace the foot valve.
   
   See our step by step diagnosis and repair advice at WATER TANK AIR LOSS SIGNS -- Keep me posted. Daniel F.

Water Pump Short Cycles Again After I've Added Air to the Pressure Tank

Our water pump often short cycles. And whenever it does, I drain and refilled the tank. But these past few months, our water pump has been a problem.

I was doing the draining and refilling for an average of every 6 days. It does its job on fixing the cycles but after few days, the pump short cycles again. What might be the problem? On 2018-02-15 by Jose

by (mod) - water pressure tank rapidly loses air charge - find the leak

Jose,

If you're sure the tank is starting fully empty, air filled, and it loses it's air charge in a few days, and your water usage volume is typical, then I suspect the tank has an air leak, maybe high in the tank or at the air valve.

More diagnosis and repair advice is at WATER TANK AIR LOSS SIGNS

Water Pressure Tank Air Valve Repair or Replacement Q&A

Tip: See the repair procedures at WATER TANK AIR VALVE REPAIRS

See more diagnostic procedures at

• WATER LEAKS OUT AT THE AIR VALVE Q&A - water comes out at the Schrader Valve
• WATER TANK AIR LEAK INDICATIONS Q&A - signs of air leaks at the tank or at its air valve

  Valve on pressure tank is leaking air when I take off the cap - is this normal?

  Just shocked well , after flood. Air presure valve was removed ,reinstalled.valve leeks air without airvalve cap. Is this normal? 2016/11/21 John

  Reply: no. tighten or replace the valve stem core.

  No, John. We shouldn't see water (nor air) leaking from the air valve.

  Stop by your auto parts store, pick up a tire valve replacement tool - you'll need this to un screw the actual valve core from the stem. Try removing, cleaning, and replacing the existing valve core, or just install a new one.

  Watch out: on some well systems, particularly those using a submersible pump and an in-well snifter valve, the above-ground snifter valve core spring is a softer one than is used in car tires since it needs to open and close at a lower pressure range.

  If the auto type replacement core gives trouble later (such as inadequate control of the air volume in a pressure tank that does not use an internal bladder) then a different core could be needed.

  If your pressure tank is one that uses an internal bladder, a standard automotive valve core will work fine.

  Watch out: if WATER is leaking out of the air valve on a tank that uses an internal bladder, then the bladder is leaking.

  Is the water tank air inlet valve repairable ?

  At our water tank the air inlet valve in leaking. Can we put a new valve on or do we have to buy a whole new tank? (Jan 22, 2015) Tina Clifford

  Reply: yes if the leak is the Schrader valve core or stem, no if the leak is in the actual tank body around the vbalve

  Tina if the leak is at the valve stem or core, that part can be replaced using an ordinary automotive tire valve tool to remove the old valve core and to install a new one.

  However when buying the new valve core you want to buy one that is designed to operate in the same pressure range as that selected by the manufacturer of your water pressure tank - which may be (and often is) quite a bit lower than that found in an automotive supply store.

  Check with the manufacturer. This may not matter for some installations but for water system air valves used in SOME designs that require automatic air venting

  See SNIFTER & DRAIN BACK VALVES and see also the article starting at the top

  of WATER TANK AIR ADD AT AIR VALVE. A low-release-pressure valve core is needed.

  Watch out: if on the other hand the leak at the air valve is around the outside of the valve and is because of rusting on the steel tank body, then it's time for a new water tank.

   

  Air is escaping around the rubber grommet going into the tank

  i have a 30 gallon pressure tank. losing air at air valve on top of the tank. changed the stem but didn't help. air is escaping around the rubber grommet going into the tank. Does the grommet just pull out to where i can replace it like on a car tire, or is it screwed in or attached to the bladder inside. Thanking you in advance for your help. 2017-03-06 by Ray

  Reply by mod: repair is possible if the tank itself is not rusted or damaged

  Ray,

  It's possible to remove and replace a water tank air valve and its mounting rubber grommet or bushing by some careful cutting and prying of the old valve and pushing in a new one.
  
  Usually the air valve is a force-fit rubber grommet - perhaps more easily installed using soapy water.

  Watch out: if the tank is rusted around the grommet or air valve or if you scratch or bend the tank while trying to get the old air valve off or while trying to install the new air valve then most likely you'll need to replace the entire tank assembly.

   

  Air valve leaks where it mounts on the water tank: do I need a new tank?

  I have a fairly new Myers MPD 20 tank, about 8 years. It is now leaking at the valve unit itself where it fits to the tank.

  Is there any solution short of buying an expensive new tank? Can it be repaired or replaced.

  It is not a big leak but over time it floods the flooring. Donatus. (Aug 13, 2014)

  Reply:

  If the tank tapping for the air valve is badly corroded your options are to tap out to a larger size, epoxy a repair fitting (which may be unreliable) or in my experience and OPINION it's better to replace the water tank. Daniel F.

  Be sure to also read the diagnostics at WATER LEAKS OUT AT THE AIR VALVE Q&A - water comes out at the Schrader Valve