How to fix the water tank air volume control device:

This article describes the repair of several problems at air volume controls including water leaks at the AVC, too much air in the water tank, not enough air in the water tank, or an air volume control that is simply not working as it should.

How to Repair a Leaky US Gauge Type WJ or Type 300L Drainback System or Snifter Valve System Pressure Tank Air Volume Control

• Leaks at the valve mount: this is a standard plumbing problem. If your pressure tank or the valve mount tapping threads are not badly corroded, remove the valve, clean all threads, reassemble using pipe sealant or teflon tape.
• Leaks at the Type WJ adjustment screw: you may be able to disassemble, clean the tapping, and replace the existing parts. Replacement parts are available from US Gauge at AMTEK [2] The company sells a Type 310 valve assembly, Spec No. 085043A
• US Gauge Type 310 WJ not working: AMTEK sells Type 310 valve seat replacements, Spec No. 085392A.
• US Gauge Type 6 or Type 300L Shallow Well AVC not working: contact the company's customer service line 727-536-7831 to ask about spare parts.
• Air leaks or hissing at the AVC are discussed separately
  
  at AIR VOLUME CONTROLS, HISSING

[Click to enlarge any image]

Recapping, both types of these air volume controls are used only on bladderless water pressure tanks - tanks that do not use an internal bladder. At above left a photo of a US Gauge a Type 6 Air Volume Control showing its operating float (that you cannot normally see as it is inside the water tank). This control is used on shallow wells and jet pumps.

Available at plumbing supplies and via Grainger online who describe the product as "Maintains Balanced Air Volume in Standard Air Over Water Storage Tanks when Using Shallow Well Pump." The installation kit includes 2" Diameter 0-100 Pounds Gauge, 48" Polyethylene, 1/4" Tubing and 1/4" Connectors

On the deep well model WJ 300 or WJ310 AVC from U.S. Gauge, the device excludes the tube connecting from the AVC to the well pump and you won't see the brass fitting on the bottom of the shallow-well AVC model illustrated at CAN I REPLACE e a Round Diaphragm AVC .

Reader Question: how to fix water leaks at a round Brady AV-series air volume control

7/16/14 anonymous said:

I had a Brady AV-30 air volume control installed when a new water pump was installed 19 months ago. What could be causing the air volume control to leak water from the middle of the thumbnut at the bottom of the control?

The thumb-nut is not loose and is apparently not to be turned with a pliers or wrench. It is leaking enough to nearly fill a bucket in 12 hours.

What is the purpose of the thumb nut? Can this leak be repaired? I have called the pump repairman, but he has not yet called back.

The pump is operating normally and is not short cycling, although it may run once every few hours due to this leak even though no other water is being used..

Reply:

The Wayne - Brady AV-series air volume controls use an internal diaphragm to operate the device.

If the diaphragm has ruptured the air volume control may leak and needs repair or replacement.

If your AV unit is assembled with screws around its round outer perimeter the device is repairable - a new internal diaphragm and spring can be installed. If the round exterior perimeter is simply crimped together, the unit is not repairable and simply is replaced.

Your model, the Wayne Brady AV30 is intended for a 42-gallon water pressure tank and is a repairable model.

There are two ports on these AVCs, a 1/4" threaded tank port and a 7/16"x24 suction port. The thumbscrew which contains a warning "do not use wrench" is an air inlet.

In addition to the air port some Brady air volume controls include a tapped gauge port. Below we give sources for purchasing this air volume control device and repair parts for it.

Brady Air Volume Controls, depending on the model, are field-repairable using a factory-supplied repair kit.

Where to buy Round Wayne Brady Air Volume Controls & Parts

• The Brady AVC is manufactured by Simmons Manufacturing Company, 1608 Highway 20 East McDonough, GA, 30252 USA, Sales Order Desk: 800-241-1935, Website: http://www.simmonsmfg.com. These air volume controls are sold at the following outlets:
• Wayne - Brady AV-series air volume controls are distributed by local plumbing suppliers in the United States & Canada and are
• Wayne - Brady AV-series air volume controls are also sold online at
  • Amazon,
  • EBay, and various online plumbing suppliers such as
  • http://www.grainger.com/product/BRADY-Air-Volume-Control-3A421
  • http://www.thehardwarecity.com
  • http://www.liquidnation.us
• Repair Kits for the repairable Brady Air Volume Control are available from the manufacturer and from various suppliers.

Notes to the table above

• Source: - http://www.simmonsmfg.com/index.php/our-products/accessories/air-volume-controls/ retrieved 7/16/14

  at AIR VOLUME CONTROLS, REPLACE

• Brady AV-45 INSTALLATION INSTRUCTIONS [PDF] in French. [English and Spanish language copies of AV-45 instructions needed - Ed. ]

• Contact: Simmons Manufacturing P.O. Box 1509 McDonough, GA. 30253 1608 Highway 20 East McDonough, GA. 30252 USA, Tel: (800) 241-1935
  

Shown below: the Brady AV-45 Zinc Air Volume Control. Excerpting from the product description at Grainger.com (a vendor of these and thousands of other plumbing and HVACR parts):

These well water tank air volume controls (AVCs) are devices that maintain the correct air pressure in well water tanks that do not have an air bladder to control water pressure in the system. The AVCs have floats that mount inside the tank or saucer-shaped diaphragms that install on the outside of the tank to detect the water level inside the tank and keep water pressure at a consistent level.

Regrettably the only Brady AV-45 INSTALLATION INSTRUCTIONS [PDF] we've found to date are in English and French.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-03-25 by Inspectapedia Com Moderator

@Ken,

Glad to assist, thank you for the nice comment. Your question helps us see where we need to research and add information.

On 2022-03-25 by Ken

Great information! Thanks again you were very helpful.

On 2022-03-24 by Inspectapedia Com Moderator - Brady AV-45 valve is not adjustable

@Ken,

Sorry for the misunderstanding.

Some bladderless pressure tank air volume controls are adjustable, such as the US Gauge WJ AVC that we explain at

AIR VOLUME CONTROL ADJUSTMENT

but your Brady AV-45 is not adjustable.

There are three apparent "fittings" on these valves:

• a threaded nipple that mounts to the water tank
• a larger threaded nipple that connects a water/air line to the water pump
• a hex-sided fitting that acts as an air valve (spring and valve parts open at factory set pressure)

Brady describes these AV-nn air volume control valves as automatic:

"Brady automatic air volume control maintains the correct volume of air in an atmospheric pressure tank ...."

The -nn suffix, such as AV-45 (your model) refers to the maximum water pressure tank size that the AVC is designed to handle.

Eg. the AV-42 is described as

Brady Air Volume Control (42 Gallon) # AV42T. Brady automatic air volume control maintains the correct volume of air in a atmospheric pressure tank up to 70 gallons capacity. Zinc die cast body, Buna N diaphragm and seal cap, brass spring and orifice; 100 PSI maximum pressure; 1/4" FNPT (Female pipe thread)tank, suction connection and gauge port; 1.01 lbs.

How does the Brady AV-45 type AVC work? This is a diaphragm type air volume control valve (hence the round disc shape of the device).

When water in the pressure tank is at a level at or above the location of the valve's mounting point on the water tank body, at each pump-on cycle the valve will inject some air into the water pressure tank.

Other AVC models such as the AVC-DWP and AVC-DWR DO include an adjustable pressure relief valve that vents excess air from the pressure tank when the pump is re-filling the tank.

For other readers: in this article series you'll see descriptions of several types of air volume controls or AVC valves:

Diaphragm air volume controls like the Brady AV's we're discussing here that inject air into the water pressure tank depending on the water level in the tank.

Float-type air volume controls that use a hinged float on a metal arm to open or close the AVC to admit air or not as water level drops or rises (suitable especially for larger water pressure tanks up to 220g).

Other Float-type AVCs for deep wells that can inject or release larger volumes of air.

AVC systems that use a snifter valve in the well and air vent at the water tank - discussed in this article series and suitable for deep wells using a submersible pump discussed

at DRAIN BACK & SNIFTER VALVE SYSTEM COMPONENTS

and though we don't see them often, Bottle-AVCs that simply inject some air into the pressure tank at each pump-on cycle (suitable for smaller water pressure tanks up to about 80 gallons)

On 2022-03-24 by Ken

I know that adjustment won't fix the leak. Just asking if any adjustment for the new valve was necessary. Thanks so much for your help. Most appreciated.

On 2022-03-23 by Inspectapedia Com Moderator

@Ken,

Adjustment is not going to correct a leak.

And no I don't think that the amount of air in the water pressure tank has an effect on the difficulties in priming the pump. Use the on-page search box for our articles on well pump priming methods.

On 2022-03-23 by Ken

The valve only leaks when pump is on. I'll have to replace it. Do I need to adjust the valve? The pump is at my cabin and I drain the system every time we leave (during winter months). I would think some water stays in the bottom of the disc and freezes. probably gave way after a while.

Would this problem be the cause of difficult priming of the pump when I recharge the system?

On 2022-03-23 by Inspectapedia Com Moderator - Brady AV-45 air volume control device is leaking

@Ken,

What's needed depends on a careful inspection of your Brady AV-45 air volume control device so as to see exactly the location of the leak. If the leakage is at the AVC base's threaded fitting you should be able to stop it by removing pressure from the water tank, lowering water in the tank until it's below the AVC mount point, then remove and re-install the device with new teflon tape on the AVC base.

If it's at the AVC pressure outlet tube threaded fitting, try re-making and sealing that fitting.

If the AVC is leaking at its moulded seam around the circumference of the AVC, then the control should be replaced.

I've included a photo of this Brady AV-45 AVC above on this page where we note that some AV models are repairable and others, not.

The AV-45 is not a "repairable" model.

On 2022-03-23 by Ken

Water leaks from the control valve (AV-45) when pump is on. I do have trouble priming the pump. Once primed and pressure reached, the valve does not leak.

On 2021-01-03 by danjoefriedman (mod)

Rodger

That sounds as if the air control valve internal diaphragm has torn and the valve is shot; I would replace it.

On 2021-01-03 by Rodger

Water spewing out of the air control valve, Brady style

 

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Continue reading at AIR VOLUME CONTROLS, REPLACE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• AIR VOLUME CONTROL ADJUSTMENT
• AIR VOLUME CONTROLS, GET RID OF
• AIR VOLUME CONTROLS, HISSING
• AIR VOLUME CONTROL REPAIR repair procedures for Brady and other air volume control devices
• AIR VOLUME CONTROL TEST
• WATER TANK AIR VOLUME CONTROLS - home
• WATER TANK BLADDERS

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AIR VOLUME CONTROL REPAIR at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

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