ST-5 Therm-X-Trol Expansion Tank (2.0 Gal Volume)

amtrol st-5 expansion tank, therm-x-trol
Click on image to enlarge
amtrol st-5 expansion tank, therm-x-trol in box







Availability: In Stock
Usually ships: within 1 business day
Qty Price
$41.50 / each
x4 $162.00 / box
(4 x $40.50)
Add to cart McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
  • Description
  • Literature
  • Reviews
  • FAQs

Amtrol ST-5 (Therm-X-Trol) is a water heater expansion tank, designed for use in domestic hot water heating systems to eliminate the potential hazards of water expansion.

Water heater expansion tank is commonly installed in a domestic hot water system that contains a backflow preventer, a check valve or a pressure reducing valve.


Amtrol ST-5 Advantages:

Eliminates the waste of energy and water, thus saving money;

Protects the water heater and plumbing fixtures from premauture failure;

Reduces potential safety hazards associated with thermal expansion;

Prevents a dangerous pressure build-up in the system;

Prevents the relief valve from going off;

Therm-X-Trol brand is the #1 choice of Professional Installers;


Amtrol ST-5 Specifications:

Factory pre-charged 40 psig;

System connection: 3/4" male threaded;

Stainless steel system connection;

Max. operating temperature: 200F;

Max. operating pressure: 150 psi;

Expansion tank volume: 2.0 gallons;

Max. acceptance factor: 0.45;

Height: 12 5/8";

Diameter: 8";

Shipping weight: 5 lbs;


Standards & Approvals:

NSF/ANSI 61®, IAPMO, SBCCI & City of Los Angeles listings.


Amtrol ST-5 Applications:

Residentail water heaters, laundromats, dormitories, office/apartment buildings, restaurants, etc.

Average 5.0 rating based on 1 review.
Nice quality tank.
By Bob the builder (from Eastern Canada) on 11/25/2011
Review for: ST-5 Therm-X-Trol Expansion Tank (2.0 Gal Volume)
I've used these in many installs and they always do the trick. The stainless steel connections eliminate any risk for rust.
Indicate an email address where you wish to receive the answer to your question.
Enter the characters (without spaces) shown in the image.
I purchased my home as new construction years ago and this model was installed. I recently purchased this unit again as a replacement but found the pressure in my house is 65psi. Is it okay to increase the pressure in the tank to match the home water pressure?
Read 1 answer
Yes, you can (and in fact have to) increase the pressure in the expansion tank to match the system pressure. You can read more about this in the installation manual (click here) on page 1.
Answered on 2/4/2013 by PexUniverse Customer Service
I am having a problem I am unable to check the pressure of the expansion tank. I replaced the valve stem and still nothing. The pop off valve is still tripping near the end of the heating cycle. When I put air into the unit my gauge on the compressor shows 40lbs. I am unable to check it with a tire gauge. Do I need a new expansion tank?
Read 1 answer
A common condition indicating that there's something wrong with the expansion tank is when the pressure relief valve goes off. If you're unable to check internal pressure, the optimal solution is to replace the tank. If you did not experience similar issues in the past, the same expansion tank model would be suitable. If you had similar issues when the tank was new, it may be best to get a larger model (1 size up).
Answered on 12/12/2012 by PexUniverse Customer Service
Related Items

Brand: Spirotherm


Price: $76.95
Add to cart

Brand: Spirotherm


Price: $155.95
Add to cart

Brand: Spirotherm


Price: $86.95
Add to cart

Brand: Spirotherm


Price: $76.95
Add to cart

The following was added to your shopping cart: X

Forgot Your Password?

Enter your e-mail address below.
You will receive an e-mail
with password reset instructions.