SKU: 88133923609

APO FPV 15mm Solar Anti Frost Protection Valve

Sale price$58.50 Regular price$65.00
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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:
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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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xyz
San Leandro, US
★★★★★ 4
Quality shoe but with a slight squeak.
Size: 10 Wide, Color: Burgundy Polished Full Grain
Nice shoes with the classic Penny Loafer design. Fit was better than another brand I tried. Only reason not 5 starts is disappointment due to a slight squeak at times when walking.
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Reviewed in the United States on August 11, 2025
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Steven D
Louisville, US
★★★★★ 5
Exact item ordered, quick delivery
Size: 9.5, Color: Black Polished Full Grain
I ordered these black Cole Haan penny loafers for casual wear with jeans, khakies, and even business casual with slacks and a jacket. They've always worked perfectly for these uses. The Cole Haan version is the most versatile and still meets my sophisticated look criteria. I wear a 9 1/2 M with almost all other shoes. I have found Cole Haan to run slightly wider and slightly shorter. This fit will work with thin and no socks and a little loose in width. . I'd likely order a 10 N next time. I tend to forget this but it runs consistent with me for Cole Haan. 5 stars for the shoe and service. My bad on the slightly off fit.
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Reviewed in the United States on January 8, 2025
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Verified Purchase
Hugh62
Fort Morgan, US
★★★★★ 1
Poor quality control - maybe outlet store leftovers
Size: 11.5, Color: Burgundy Polished Full Grain
The two shoes were not the same size. They were both labeled 11 1/2 but one shoe was larger than the other and the fit was poor. I returned the first pair and ordered a replacement. This time the shoes were close to the same size but too loose and the left one has sewing issues. I've bought Johnston & Murphy for years because of the quality. These were to replace an existing pair of burgundy penny loafers that have finally worn out (even after several heal/sole replacements). That is the expected quality. I suspect Nashville Shoe Warehouse may be handling shoes that didn't measure up for the quality; more like an outlet mall than getting the J&M quality I've come to expect. Update: went to Johnston & Murphy site to buy "direct" from the manufacturer. There were several recent reviews where the shoes were long and didn't fit properly. Genesco - please step up the manufacture / crafting of these classic shoes to the level of quality they used to have.
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Reviewed in the United States on July 21, 2025
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Fabric Crazy
Grantham, US
★★★★★ 5
Really nice shoes
Size: 9, Color: Black Polished Full Grain
My husband enjoys wearing these shoes. Very classy looking. They fit well. They arrived quickly. He liked them so much he ordered another pair in a different color which have worked out just as well.
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Reviewed in the United States on February 3, 2026
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tjw
San Leandro, US
★★★★★ 3
Way too narrow
Size: 9.5 Wide, Color: Burgundy Polished Full Grain
I ordered a wide in this shoe, but it was still way too narrow. I had to return them. Otherwise, it looked like a nice quality shoe.
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Reviewed in the United States on February 12, 2026

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