Sub Zero Covers
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Model fitment

Ames 4000SS backflow cover

Ames 4000SS backflow cover: The 4000SS is the big stainless Ames RP: the same 37-inch-at-2½" body family as the Watts 774, with a relief valve that hangs a foot below the pipe. Length and depth together are what set the cover.

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What it is

The Ames 4000SS is a reduced pressure zone assembly in 2½" through 12" on a 300-series stainless body with a bottom-mounted relief valve and, on current units, a flood sensor on the relief. The 5000SS is the RPDA version with a metered bypass RP for fire service. NRS or OS&Y gate shutoffs; horizontal installation only.

Length matches the Watts 774 and Ames 2000SS families: 37" at 2½", 40" at 4", 48½" at 6", 52½" at 8". The relief valve is the deep part: 10½" below the pipe centerline through 4", 11½" at 6", 12½" at 8" and up. That is three to four inches deeper than a Colt or a Watts 957.

What matters for the cover

Length puts it a size up from the Colt. At 2½" and 3" the 70 × 40 is the price-list match and clears the 37"–38" body with gates; at 4" the 85 × 40. If a customer says "Ames RP" without a model, ask whether it is a Colt or a 4000SS before you pick.

Depth plus discharge. 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. Ames specifies 12" minimum drain clearance under the relief valve; the cover's base has to leave that side open.

Height. OS&Y stems at 16⅜" above centerline on 2½" and 37¾" at 8" set the height; the relief valve sets the bottom. The 40" and 50" cover heights are built for a pad-mounted stack; a tall riser needs a photo.

5000SS. The bypass adds width on one side. Photos first, especially at 6".

Stocking

The 4000SS shows up on commercial domestic service and the 5000SS on fire lines in Ames territory. Fire protection distributors stock the 85 × 40 and 100 × 50; plumbing houses the 70 × 40 and 85 × 40. It shares covers size for size with the 2000SS double check, which sits in the same body without the relief valve.

Ordering

Name the size and the shutoff type, and say 4000SS rather than "Ames RP" so it is not confused with the shorter Colt. With OS&Y gates the 70 × 40 covers 2½" and 3", the 85 × 40 the 4", the 100 × 50 the 6", the 120 × 50 the 8". A 5000SS needs the bypass-side photo.

Published dimensions

Ames 4000SS 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
2½"37"16.375"10.5"70 × 40 (DS7040) · N-shape NS3
3"38"18.875"10.5"70 × 40 (DS7040) · N-shape NS3
4"40"22.75"10.5"85 × 40 (DS8540) · N-shape NS4
6"48.5"30.125"11.5"100 × 50 (DS10050) · N-shape NS6
8"52.5"37.75"12.5"120 × 50 (DS12050) · N-shape NS8
10"55.75"45.75"12.5"130 × 55 (DS13055) · N-shape NS10

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

Does a cover for an Ames Colt C400 fit a 4000SS?
Not reliably. The 4000SS is six inches longer at 2½" and 4" and its relief valve hangs several inches deeper. Order by model.
Which cover fits a 6" Ames 4000SS?
The 100 × 50 open-top cover (DS10050) is the price-list match for 6". Confirm the riser height and leave the relief-valve side of the base open to 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 Ames product?
No. Sub Zero Covers is an independent manufacturer. We pattern covers to the published dimensions of Ames assemblies; Ames does not endorse or supply them.

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