SKU: 88133923609

APO FPV 15mm Solar Anti Frost Protection Valve

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Description

APO FPV 15mm Solar Anti Frost Protection ValveOverview The APO Anti Frost Protection Valve FPV is designed to protect solar collector panels from frost damages. The APO FPV is compatible and a direct swap for other brands such as AVG and Caleffi frost protection valves. The FPV anti frost valve employs a wax filled piston inside coupled with a spring to open or shut the valve. The wax will contract or expand according to the ambient air temperature in order to move the piston. To extend the APO

Overview

The APO Anti Frost Protection Valve FPV is designed to protect solar collector panels from frost damages. The APO FPV is compatible and a direct swap for other brands such as AVG and Caleffi frost protection valves.

 

The FPV anti frost valve employs a wax filled piston inside coupled with a spring to open or shut the valve. The wax will contract or expand according to the ambient air temperature in order to move the piston. To extend the APO FPV anti frost valve service life span, an optional 100mm "dead leg" extension fitting as shown in the last few photos is offered at an extra cost and is highly recommended.

 

When a frost condition is present, the wax contracts sufficiently enough to compress the string and open the FPV valve seat causing a water leakage from the solar hot water panels. The hot water from the storage tank will move into the solar panels to fill the void from the leakage. This warm water will in turn heat up the solar panels and protect the panels from freezing. At the same time the FPV anti frost valve heats up itself with the solar panels from the hot water, until the FPV piston shuts off the leakage by closing the valve sealing seat, as the wax in the piston expands. The cycle will then repeat when the solar panels slowly lose heat and the FPV anti frost valve opens again. 

 

Unfortunately, this piston/wax mechanism can often be damaged by the extreme heat generated by the solar panels during the summer. When the first frost comes in winter, the valve will usually fail to automatically shut off and cause non-stop water leakage from the roof. The "dead leg" extension fitting keeps the FPV anti frost valve further away from the panel and protect the valve from the heat. The FPV life span is significantly extended. In fact, some other manufacturers such as Caleffi will require such 100mm extension for their anti frost valves' warranty to be honored. 

 

Only one APO FPV anti frost valve is required for one solar hot water system with 2 or 3 solar panels. The FPV anti frost valve should only be installed at the bottom of the solar panels opposite to the cold water inlet, where the temperature is lowest. It is recommended to only use the supplied red fiber glass washer gasket and use the optional rubber seal included as a spare when used on the solar panels. Being installed at the right angle corner of the solar hot water panels, debris can accumulate inside the valve body and hence FPV frost valve should be flushed out periodically every 2 years as a maintenance schedule.

 

 

Technical Details

  • Manufacturer: APO
  • Model: FPV
  • Thread Size: 1/2" BSP (15mm) female swivel loose nut
  • Physical Thread Size Measurement: 20.995mm internal diameter (Please refer to the BSP sizing chart in the photo gallery)
  • Material: Lead Free DR Brass and Stainless Steel
  • Activation Temperature: 3-5 deg 
  • Optional Dead Leg Extension Fitting: Watermark Approved DR Brass
  • Intended Use: Solar water heaters in frost prone area
  • SKU: APO-FPV & APO-FPV-E

 

Package Contents

  • APO FPV anti frost valve with optional 100mm extension 
  • Package weight 210g (380g with the extension fitting)

 

 

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. 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
SKU: 88133923609

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4.5 ★★★★★
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Taylor Ashley
Battle Creek, US
★★★★★ 4
Okay serum, not as good as the cream though
I am obsessed with the cream version of this so I thought I’d give this a try. The dropper top allows for easy application. The formula is light and non greasy and absorbs easily. No harsh fragrances. I would use it when I had eczema flares on my face and feel like it didn’t work near as well in helping with skin irritation as the cream does. As of now I don’t use it as part of my regular skin care. Do I think it’s a bad product? No, but it didn’t really work wonders for me. Not sure I would purchase again.
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Reviewed in the United States on May 21, 2026
E
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Elizabeth from Houston
Carnegie, US
★★★★★ 5
Helps with redness and softens skin
I have sensitive, mild rosacea skin. Had a facial recently and the aesthetician suggested I get a serum to help with moisturizer as I am almost 40. I’ve tried a lot of serums and either they are sticky and not really hydrating or break my skin out in a rash. This serum is amazing. Helps calm the redness in my cheeks and my skin is moisturized and soft all day. It feels a little sticky at first but it goes away. I apply in this order OSEA sea mineral mist toner to prep the skin, this serum and top off with Chanel La Solution 10 for sensitive skin.
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Reviewed in the United States on December 27, 2025
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Verified Purchase
carolyn
Belleville, US
★★★★★ 5
Sensitive skin
Such a good product. I use after micro needling when skin is sensitive. Also a great product to use as a barrier serum when starting tretinoin cream.
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Reviewed in the United States on April 24, 2026
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Verified Purchase
Lindsay
Natrona Heights, US
★★★★★ 5
Saved my skin during an eczema flare up
This saved my skin! I had an eczema flare on my face, and my usual products weren’t working. A friend recommended the Avene brand and within 3 days of using this rescue barrier serum, my flare was almost completely gone! This saved my face!
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Reviewed in the United States on April 11, 2026
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B Helton
Natrona Heights, US
★★★★★ 1
PLEASE REVIEW — FORMULA CHANGED!!!
I wish I would’ve posted a review PRIOR to the formula changing but just know that I LOVED this serum. I’ve struggled with hormonal acne (PCOS) and eczema for as long as I can remember. Finally, last summer my dermatologist put me on (3) different RX including Spironolactone and Accutane. I was so tired so I stopped everything except for CeraVe cleanser, retinol (Tretinoin) and CeraVe healing ointment. My made up skin routine was working until I used too much Tretinoin and burned my face. I had read great reviews about this product so I thought, I might as well try it — and IT WORKED! I’ve been using this product for almost a year and I loved it. However, 3 weeks ago when I ordered it, I noticed the bottle had a green tint. I could tell after one use that the feel of the serum was different, more watery, not as thick as it used to be. The smell was also different. Still, I kept using it for nearly 2 weeks and I experienced 2 breakouts! Sure enough, I stopped the product and within a few days, my skin was back to normal. I am very upset because as someone who has extremely sensitive skin, this worked but unfortunately, the new formula isn’t for me.
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Reviewed in the United States on May 14, 2026

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