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Description
Flexcon PH5 Thermal Expansion Tank | 2.1 Gallons – 3/4" Stainless Steel ConnectionFlexcon PH5 Thermal Expansion Tank 2. 1 Gallons 3 4" Connection Product Overview The Flexcon PH5 Thermal Expansion Tank is a premium 2. 1 gallon potable water expansion tank designed to protect residential and light commercial plumbing systems from thermal pressure buildup. Built with Flexcons advanced diaphragm technology and a rugged 16 gauge cold rolled steel shell, the PH5 delivers long lasting performance and reliable system protection for water
Flexcon PH5 Thermal Expansion Tank 2.1 Gallons – 3/4" Connection
Product Overview
The Flexcon PH5 Thermal Expansion Tank is a premium 2.1-gallon potable water expansion tank designed to protect residential and light commercial plumbing systems from thermal pressure buildup. Built with Flexcon’s advanced diaphragm technology and a rugged 16-gauge cold-rolled steel shell, the PH5 delivers long-lasting performance and reliable system protection for water heaters and closed-loop potable systems.
This model features a 3/4" stainless steel connection, a 100% butyl rubber diaphragm, and an anti-microbial polypropylene lower water chamber to maintain sanitary conditions and resist corrosion. Each tank is factory tested for seam integrity, structural reliability, and pre-charge accuracy, making it a trusted choice for new installations and replacement jobs.
Features & Benefits
- 2.1-gallon thermal expansion tank for potable water heater systems.
- 16-gauge cold-rolled steel tank for long-term durability.
- Appliance-quality exterior paint suitable for indoor or outdoor installation.
- 100% butyl rubber diaphragm for reliable expansion and contraction.
- Anti-microbial copolymer polypropylene lower water chamber for sanitary performance.
- 3/4" stainless steel connection resists corrosion and maintains water quality.
- Brass air valve with O-ring seal for secure, leak-resistant pressurization.
- Factory-tested for high pressure, seam weld integrity, helium leak, and pre-charge.
- Backed by a 5-year manufacturer warranty.
Specifications
- Model: PH5
- Tank Capacity: 2.1 gallons
- Connection Size: 3/4" stainless steel
- Tank Material: 16-gauge cold-rolled steel
- Diaphragm Material: 100% butyl rubber
- Lower Water Chamber: Anti-microbial copolymer polypropylene
- Exterior Finish: Appliance-quality paint
- Air Valve: Brass valve with O-ring seal
- Testing: High pressure, seam weld, helium leak, and final pre-charge check
- Warranty: 5 years
- Typical Applications: Potable water heater thermal expansion control
- Cross References: Amtrol ST-5 & T-5; Bell & Gossett PT-5; Calefactio HGTE-8; Watts PLT-5
Installation Tips
- Verify the PH5 is correctly sized for the water heater and system pressure.
- Install the tank on the cold-water supply line feeding the water heater.
- Set the tank pre-charge to match the building’s static water pressure before installation.
- Use approved thread sealant or Teflon tape on the 3/4" stainless steel connection.
- Mount the tank in a vertical position whenever possible; support if installed horizontally.
- Check for leaks and confirm system pressure after installation.
- Inspect the tank and verify pre-charge annually as part of routine plumbing maintenance.
FAQs
-
What does the Flexcon PH5 thermal expansion tank do?
It absorbs excess pressure created when water expands as it is heated in a closed plumbing system, helping protect fixtures, valves, and the water heater. -
Is the PH5 suitable for potable water?
Yes. The PH5 is designed for potable water systems, with a butyl diaphragm and anti-microbial polypropylene water chamber. -
Which models does the PH5 replace?
It is a direct replacement for Amtrol ST-5 & T-5, Bell & Gossett PT-5, Calefactio HGTE-8, and Watts PLT-5 expansion tanks. -
How often should I check the pre-charge?
Flexcon recommends checking the air pre-charge at least once a year, or any time system pressure issues are suspected. -
Can the PH5 be installed outdoors?
Yes. The appliance-quality paint finish allows for indoor or outdoor installation, provided the tank is protected from physical damage and extreme conditions.
Product Literature:
Submittal Literature
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.5 ★★★★★
Based on 25 reviews
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Product Reviews
★★★★★ 4
Comfortable and Supportive, but Adjust the Filling
Color: White-cooling Basic, Size: Queen(Pack of 2), Color: White-cooling Basic, Size: Queen(Pack of 2)
I’m very happy with this pillow. The size is big and it feels soft while still providing good support, perfect for midnight scrolling on TikTok.
One thing to keep in mind is that it can feel a little too tall if you use all of the filling that comes with it. The good news is that you can easily adjust the amount of filling to find the height that works best for your sleeping position. Once I customized it, it was much more comfortable.
Overall, great quality, comfortable, and worth the purchase.
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Reviewed in the United States on June 3, 2026
★★★★★ 5
BEST PILLOWS EVER!!!
Color: White-cooling Basic, Size: Queen(Pack of 2)
I am very picky with my pillows because I have a bad neck and I can never seem to find a good pillow. But I tried this pillow because it had everything I was looking for and the price was great! You get two of them and they are absolutely awesome.! normally I would need to lay on two pillows to try and get comfortable but with these pillows I just lay on one and I wake up with no neck pain. They really have a nice cooling effect. They actually puff up immediately after opening them. All you have to do is just shake them up and the pillow just puffs straight up.. It comes with extra cushioning if you want it to make it firmer and if you don’t want it as firm as it is, you can actually take some out. It really is such a beautiful pillow. It’s perfect in every way to me being such a picky pillow person.
You just lay your head down on it and it forms around your neck and your head and when you get up, it goes right back to its normal form. It doesn’t get flat and I love it. I completely recommend this to anyone who is a person who has a hard time finding a really good pillow.
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Reviewed in the United States on April 12, 2026
★★★★★ 5
Top of the line, best pillows Ive ever had
Color: White-cooling Basic, Size: Queen(Pack of 2)
These pillows are top of the line! I bought them in 2024 and they are still fluffy. When they lose a little fluff, you just punch em around a little bit and voila, like new again. They have kept their shape cery well and do great for cooling. I haven't had to add more filling yet either. I just laid my head on one and thought, I need to do a review cause everytime i lay on these pillows its like clouds. My head is heavy and this is relief :-D
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Reviewed in the United States on May 21, 2026
★★★★★ 3
Weird smell
Color: White-cooling Basic, Size: Queen(Pack of 2)
The pillows are great for someone looking for something cool and comfortable. We loved them so much that we bought a second pair. However, we were seriously disappointed with the odor of our last purchase. They give off a strong and indescribable chemical/burning plastic smell so nauseating that it’s difficult to sleep with. We’re hoping this issue will resolve with a couple more washes of the pillow cases, but am worried the source is the stuffing itself.
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Reviewed in the United States on May 28, 2026
★★★★★ 5
helped treat my sore neck
Color: White-cooling Basic, Size: Camping Pillow(Pack of 1)
This pillow — after dialing in the right amount of shredded foam — has greatly helped my sore neck. Initially, I had to remove some foam. Then I gradually added foam until it reached optimum comfort and support.
It is also CPAP-friendly — especially when I position my head near the pillow's edge. (I am a left-side sleeper.)
I like the travel size because I use a bulky hugging pillow to ease stress on my shoulder and elbow. That makes my side of the bed feel cramped if using a larger head pillow. A smaller pillow is easy to flip end-to-end in the middle of the night.
I have spent lots of money on pillows over the years, but this is the best I've ever had for relieving [1] neck pain and [2] CPAP mask seal problems. Very comfortable, supportive, and affordable.
I did not notice any unpleasant smell — and I am usually sensitive to that kind of thing.
Would highly recommend.
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Reviewed in the United States on May 7, 2026