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Chesprocott Health District - News: Which Ballcock (Toilet Fill Valve) Will Fit My Tank?
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Section: Toilet Tank Information
Which Ballcock (Toilet Fill Valve) Will Fit My Tank?
Last Update: Sep 12, 2009



Two-piece gravity flow toilets have been the most popular and economical style of toilet for nearly a century. Tank sizes and shapes from countless toilet manufacturers have varied widely.

Many of the new 1.6 gallons per flush (gpf) toilets have tank styles that are taller & narrower by several inches. In tanks with the top of the overflow tube (flood plain) 7" to 9" above the bottom of the tank, one of our standard products (Burlington 20A or Scoville 16A) is the best choice.

For tanks with oveflow tubes more than 9" tall, we recommend the NEW Burlington 20A ADJ and Scoville 16A ADJ Models. These ADJ Models eliminate taking measurement for fit, except for the length of the float rod to use. ADJ Models are a convenience for plumbing service professionals and end users because they fit all tanks, allowing the installer to set the height in conformance with anti-siphon plumbing codes [with the "critical level", marked "C-L" on each valve body at least 1" above the top of the overflow tube.] The installed height of these ADJ Models can be easily adjusted from 9" to 13" -- a range that fits virtually all two-piece gravity flow toilet tanks.

Exceptions to the above:
(1) INSIDE TANK HEIGHT MEASUREMENT LESS THAN 10" -- The ballcock to use in shallow tanks with an overflow tube less than 7" high will require the Burlington 20A XS [Extra Short] Model if the installed (overall) height of the Standard 20A or 16A is too tall for the inside height measurement of the tank with the tank top installed.
(2)  MULTI-FAMILY APARTMENTS, HOTELS, INSTITUTIONS -- For maintenance professionals in complexes with numerous toilets (same toilet model throughout the facility) that require fill valve replacement, we offer MT (+1") and XT (+2") Models of both the 20A and 16A ballcocks. These "Special Order" Models often fit the tanks correctly and are an alternative to using ADJ Models.

The four measurement steps to verify correct fit are as follows:

1. Measure the distance from the bottom of the tank to the top of the “flood plain”(normally the top of the overflow tube that is part of the flush valve) and/or the Critical Level (C-L) if visible on the fill valve being replaced.

2. Check the table below* to identify the Model(s) that conform best to the critical level requirements in plumbing codes.

3. Measure the inside height (H) of the tank to verify that the Model selected will not exceed the tank height. This is seldom a problem, but it is worth checking.

The overall height, as installed, of each ballcock model is:

#20A XS = 8-3/4”     #20A = 10”                #20A ADJ = 9" to 13"
#20A MT = 11”         #20A XT = 12”
#16A = 10”              #16A MT = 11”           #16A ADJ = 9" to 13"
#16A XT = 12”         

4. CESCO BRASS packs each ballcock model with the length float rod most commonly needed.

You can shorten a brass float rod by over 2” since the 1-1/2” thread length at each end can be cut. Float rods are available from CESCO BRASS in even lengths from 5” through 10”.

To eliminate the need for cutting to length, use the following formula and order the ballcock model noting the length length (round down) needed:

Note: “L” is the distance from the center of the ballcock to the right inside wall of the tank, round down)
   All Burlington models – L minus 6” (allows for 5” float ball)
   All Scovill models – L minus 9” (allows for 5” float ball plus 3” lever extension)
* A rough guideline to select a Burlington or Scovill model for best fit:
If distance from bottom of the tank to top of overflow tube is:
Critical Level (C-L) as measured or implied
Burlington Anti-Siphon Ballcock Model Number
20A ADJ or ...
Scovill Anti-Siphon Ballcock Model Number
16 ADJ or ...

Under 7”
Under 8”
20A XS
7 to 8”
8 – 9”
8 to 9”
9 – 10”
20A MT
16A MT
9 – 10”
10 – 11”
20A XT
16A XT
Over 10”
Over 11”

Which Ballcock (Toilet Fill Valve) Will Fit My Tank?
Selecting the correct fill valve (ballcock) replacement model is not difficult if guided by the listed four steps.


Barry E. Walter Sr. Co. 2550 East Platte Avenue - Fort Morgan, CO 80701 - 800-767-5552

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