Sub Zero Covers
Large green insulated backflow cover wrapped around a wide double-check detector assembly, with the red valve stems and chain left above the cover for testing.
Wide assembly — valve stems left clear for testing

Model fitment

Febco 860 backflow cover

Febco 860 backflow cover: The 860 is Febco's in-line small RP and the one that replaced the 825Y on most new work. Compact end to end, but on the 1¼" through 2" sizes the relief valve drops 7½ inches below the pipe. That depth is the fit issue.

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What it is

The Febco 860 (860U with union ends, LF860 lead-free) is a bronze in-line reduced pressure assembly in ½" through 2". Single access cover on top, four test cocks, ball-valve shutoffs, and a relief valve mounted straight under the body. It serves domestic, irrigation, and light commercial service anywhere Febco is on the spec.

There is also an LF860 Large in 2½" through 10" on a ductile-iron body. That is a different assembly with a different cover; it appears in the cover finder under its own entry.

What matters for the cover

Relief valve depth. On ¾" and 1" the relief valve sits about 3½" below centerline, ordinary for the class. On 1¼", 1½", and 2" it drops to 7⅝". A cover that closes at the pad has to reach around that without sealing under it. The relief valve under the body has to drain. Set the cover so the base closes to the pad around the assembly but never seals under the relief port.

Short lay length. The 860 is compact: 10¾" at ¾", 17⅝" at 2". The 20 × 20 fits the ¾" and the 24 × 24 the 1"; at 1¼" through 2" the 30 × 24 is the closest fit of the price-list group. Union-end (860U) builds add roughly 2"–3" and may push a 2" onto the 36 × 24.

Freeze sensor option. The FZ version carries a sensor on a test cock. It does not change the envelope, but leave the sensor lead a path out of the cover.

Stocking

The 860 is the small RP irrigation supply and plumbing houses sell most in Febco markets, so its covers move in the same ratio: mostly ¾" and 1", a steady trickle of 1½" and 2" for commercial services. Pair it with the Febco 850 double check, which shares the body length and takes the same small covers.

Published dimensions

Febco 860 / 860U / LF860 envelope, by size

Reduced pressure zone (RP / RPZ). Dimensions in inches from the manufacturer's spec sheet with standard shutoffs. Length is end to end; heights are measured from the pipe centerline up to the highest point and down to the relief valve or body. The stock cover column is the price-list mapping for that pipe size, ordered closest fit first.

SizeLengthAbove CLBelow CLStock cover
¾"10.75"3.125"3.5"20 × 20 (DS2020), 24 × 24 (DS2424)
1"12.5"3.375"3.625"20 × 20 (DS2020), 24 × 24 (DS2424)
1¼"15.875"4.25"7.625"30 × 24 (DS3024), 36 × 24 (DS3624), 42 × 24 (DS4224)
1½"16.375"4.25"7.625"30 × 24 (DS3024), 36 × 24 (DS3624), 42 × 24 (DS4224)
2"17.625"4.25"7.625"30 × 24 (DS3024), 36 × 24 (DS3624), 42 × 24 (DS4224)

Confirm the fit against the assembly in front of you: unions, strainers, and OS&Y gates add length and height beyond the standard sheet. Cover finder · How to measure

Common questions

Which cover fits a 2" Febco 860?
The 30 × 24 closed-top cover (DS3024) is the closest fit for the 17⅝" standard build. A union-end 860U runs longer; the 36 × 24 (DS3624) gives it room.
Does the deep relief valve on the 1½" and 2" need a special cover?
No, the 24" cover height reaches it on a pad-mounted assembly. What matters is not sealing the base under the relief port, so the discharge can drain.
Is this a heated enclosure?
No. Sub Zero Covers are insulated, unheated covers (R-13 standard, R-30 extreme weather). They are not ASSE 1060 listed enclosures. Where a utility or spec requires a Class I heated enclosure, that is a different product; ask sales before quoting.
Is this an official Febco product?
No. Sub Zero Covers is an independent manufacturer. We pattern covers to the published dimensions of Febco assemblies; Febco does not endorse or supply them.

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