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Installation and Maintenance Instructions Nibco ® True Union Style Ball Valves

Chemtrol Union-End Ball Valves can be fitted with socket, threaded, or flanged end connections. When joining union-end valves, or when flanging end connectors, never make the joint to the end connectors while they are attached to the valve body. Remove the union nuts and end connectors from the valve cartridge first. In order to prevent mishaps with the union nut, slide it (smallest bore first) over the pipe or nipple and flange hub (when flanging) before making the joint to the end connector.

Threaded-End Valves–
Caution: Do not overtighten threads. Usually, one to two turns beyond hand-tight using a suitable strap-wrench, if necessary, is sufficient. (ANSI B1.20.1 defines hand-tight as 4 to 5 threads for sizes through 2" and 5 to 6 3/4 threads for sizes over 2".) 

Socket-End Valves

Caution: Do not allow primer or solvent cement to come in contact with the sealing face of the end connectors. When joining the fixed end of a single union valve, place the ball in the open position to allow for proper drying and to avoid primer or solvent cement contacting internal components of the valve.

 Installation Instructions

Six Step Application Techniques

Components should be wiped clean, pipe squarely cut, deburred and beveled according to the preparation instructions on page 16. Since the solvents in the cement and primer will absorb water, but water is deleterious to the joining process, the joint surfaces must be dry at the time of joining.


Primer Application

1. Using a stiff olefin or polyester crimped-bristle brush, apply primer to the fitting and pipe-end in a 3-step process alternating from fitting to pipe. Apply primer to the fitting freely. Wet the substrate of the socket surface by maintaining a rapid and vigorous scouring motion of the applicator over the entire inner socket for five to fifteen seconds. Re-dip the applicator and continue as necessary, but avoid puddling inside the fitting beyond the socket.

2. Apply primer to the outer pipe-end surface with the same vigorous scouring motion of the brush, re-dipping the applicator every five to fifteen seconds as necessary. Make sure that the evenly primed length of pipe is at least equal to the fitting socket depth. Quickness is of the essence in order to scrub primer into the surfaces and attain moistened substrata. Note that the pipe-end can be cradled and rotated on a notched block of wood, if working alone, to make application easier and to keep the surface clean.

3. Re-apply primer to the fitting socket in the same manner. When a continuous peel of a few thousandths of an inch thickness can be scraped from the primed surface with an edge, such as a knife blade, the substrate has been adequately primed for a joint. With practice one will learn to observe a slight tackiness and swell in the surfaces when priming is adequate. Alternate applications of the primer always start with the female component. Cementing should not begin until priming is adequate.


Solvent Cement Application

4. Before the primer dries, continue the alternating surface approach by applying solvent cement to the pipe and fitting in a 3-step process. Use a second plastic crimped-bristle brush to spread a continuous film of cement on the outer pipe-end surface for a length at least equal to that of the fitting socket depth. The cement film should be such that it does not run as a sheet and drool from the exterior or into the pipe interior. And the film thickness need be only thick enough to trap the continuing penetration of solvent into the pipe substrate.

5. While the moistened substrate of the fitting socket is still soft and swollen from priming, quickly spread a continuous film of solvent cement onto the entire socket surface. Avoid puddling and run-off of the cement anywhere in the fitting, or beyond the socket depth in belled-end pipe. The cement film need be only thick enough to trap the continuing penetration of solvent into the substrate and to provide an immediate and continuous wet filet around the pipe chamfer during its eminent insertion into the fitting socket. Most of this cement will be pushed ahead by the pipe throughout its insertion to the full depth of the socket. A final excess of cement at the bottom of the socket should be avoided because it cannot be removed. Large puddles formed inside the pipe and/or fitting bore serve to dramatically extend the drying time of these solvent affected areas, which translates to reduced strength of the parent material until drying does occur. Mounds of dried cement may also ultimately act as blockages to fluid flow, resulting in unacceptable pressure loss.

6. Put a second coat of solvent cement on the pipe-end. This completes the six steps of alternate surface application for a joint – three of primer and three of cement – starting with the female component. Cement layers on the pipe must be without voids and sufficient to provide an immediate and continuous wet filet around the socket entrance radius/chamfer during the eminent insertion of pipe into the fitting socket. Excess cement will be pushed off the pipe throughout its insertion to the full depth of the fitting socket. However, it is critical that the two wet beads – an inside one around the pipe chamfer and an outside one around the socket chamfer – be maintained to form vacuum seals while joining. Although much of the cement will be scraped off both the pipe and socket during joint insertion, some must be redrawn, by vacuum, to back-fill the diametrical gap between pipe and fitting socket. Air will back-fill the joint if either of the wet bead dynamic seals is broken during joint insertion, resulting in a loss of bonding area.



Pipe Insertion

Immediately upon finishing the application of cement, and before it begins to dry, the pipe must be inserted squarely into the fitting socket. Too much time has elapsed if either of the surface films has dried to the point that the film folds in the socket chamfer upon pipe insertion, rather than forming a wet bead at that location. Rotation of the pipe / turn in the socket, following pipe insertion to the full socket depth, completes the joint. This encourages complete distribution of the cement and its commingling with joint surfaces. In addition to a crew size of two being mandatory for 6" and larger pipe, rotation of the pipe in the fitting may be omitted for this size.


Flanged-End Valves–


Flanging is used extensively for process lines that require periodic dismantling. Gasket seals between the flange faces should be an elastomeric full flat faced gasket with a hardness of 50 to 70 durometer A. For chemical environments too aggressive for neoprene another resistant elastomer should be used. When it is necessary to bolt plastic and metal flanges – use flat face metal flanges – not raised face, and use recommended torques shown in table under ”Installation Tips.“



Bolt circle and number of bolt holes for the flanges are the same as Class 150 metal flanges per ANSI B16.5. Threads are tapered iron pipe size threads per ANSI B1.20.1. The socket dimensions conform to ASTM D 2467 which describes 1/2" through 8" sizes and ASTM D 439 for Schedule 80 CPVC which gives dimensional data for 1/2" through 6". Internal Chemtrol specifications have been established for the 10" and 12" PVC patterns and 8" CPVC design, as well as socket designs for polypropylene and PVDF.


Pressure Rating

As with all other thermoplastic piping components, the maximum non-shock operating pressure is a function of temperature. Maximum pressure rating for Chemtrol valves, unions and flanges is 150 psi.



The faces of flanges are tapered back away from the orifice area at a 1/2 to 1 degree pitch so that when the bolts are tightened the faces will be pulled together generating a force in the water way area to improve sealing.


Installation Tips

Once a flange is joined to pipe, the method for joining two flanges together

is as follows:

1. Make sure that all the bolt holes of the mating flanges match up. It is not advisable to twist the flange and pipe to achieve this.

2. Use flat washers under bolt heads and nuts.

3. Insert all bolts. (Lubricate bolts.)

4. Make sure that the faces of the flanges mate snuggly prior to tightening of the bolts.

5. The bolts on the plastic flanges should be tightened by pulling down the nuts diametrically opposite each other using a torque wrench. (See

diagram below) Complete tightening should be accomplished in stages. The final torque values are shown in the table below. Uniform stress

across the flange will prevent leaky gaskets.

6. If the flange is mated to a rigid and stationary flanged object, or to a metal flange, the adjacent plastic pipe must be supported or anchored to

eliminate excessive stress on the flange joint.


Flange Size

Recommended Torque

1/2” – 1-1/2”

10 – 15 ft. lbs.

2” – 4”

20 - 30 ft. lbs.

6” – 8”

33 - 50 ft. lbs.


*For a well lubricated bolt with flat washers under bolt head and nut. The following tightening pattern is suggested for the flange bolts


Caution: Do not overtighten flanges. When flanging the fixed end of single union valves, care should be taken to properly align the flange bolt holes, unless Van Stone type flanges are used.


Valve Cartridge–After allowing the proper joint drying time, end connections may be joined to the valve cartridge. O-rings provide the seal between the valve cartridge faces and the end connectors. Ensure that these O-rings are clean and in their proper grooves before slipping the valve cartridge between its end connectors. Slide the union nuts over the end connectors and screw onto the valve cartridge threads, no more than hand tight.


Caution: Do not overtighten. Once the end connector engages the O-ring seal, no more than 1/8 to 1/4 turn of the union nut will fully compress the O-ring in its groove. The pipe supports surrounding

the valve must be loose and the adjoining piping must be well aligned with the valve. The union nuts cannot be expected to bend and/or stretch the adjoining pipe in order to allow the end connectors to make the required flush seal against the valve cartridge faces.


Adjustment–The “squeeze” on the operating envelope within the cartridge of Tru-Bloc Model-C Valves is optimized during assembly at the factory. 100% of these valves are tested for shell leaks and seat leaks in both directions. Since the seat-carrier, with its seat-energizer O-ring, is adjusted to achieve O-ring compression with no leaks, field adjustment should not be required. The seat-carrier in multiport and diverter valves is of the Model-A design, meaning that it is not fastened to the valve body with internal threads.

Therefore, the union nut on the valve end with “ADJ” marked on the body serves the dual purpose of external adjustment for “squeeze” on the operating envelope within the cartridge, preventing leakage across the ball, as well as compression of the face-seal, preventing shell leakage at the cartridge face. Upon installation of multiport or diverter valves, with the handle parallel with the body and fully against the handle/body stop, tighten that union nut on the “ADJ” body end while minutely operating the handle off the stop and back to the stop. The handle turning torque should become snug, but not excessive when the valve is properly adjusted for leak-free operation. If proper adjustment cannot be made by hand tightening

the union nut (valves larger than 1-1/2"), a suitable strap-wrench may be used. Caution: Do not overtighten. Do not adjust the union nut with the handle in any position other than fully parallel or

perpendicular to the body.



Should a valve need repair, depressurize and drain the system on all sides of the valve. Loosen the valve union nuts and slide them back over the end connectors. To minimize downtime, it may be advisable to have a replacement valve cartridge ready to install in place of the one to be repaired. An advantage of the Chemtrol design is that the current model is interchangeable with all earlier models. Disassemble valve cartridge as follows:


1. Turn handle to be perfectly perpendicular to valve body.

2. Using a Chemtrol spanner wrench1, unscrew the seat-carrier (Tru-Bloc Model-C) by rotating in the counterclockwise direction. If the valve is of an earlier Tru-Bloc vintage (Model-B), it will be a retaining ring that is removed. If the valve has the original seat-carrier design (Model-A; Tru-Bloc feature not included; multiport or diverter), this step is unnecessary.

3. Insert a soft, blunt instrument into the valve end marked with the FLOW arrow and push the ball out of the valve end marked with the ADJ. arrow. In Model-A and Model-B valves the seat-carrier will also be pushed out by the ball.

4. Remove the handle from the stem by pulling upward and away from the body.

5. Examine all parts and replace any damaged or worn components. If the body is damaged, replacement of the entire valve cartridge is recommended. The current Model-C cartridge is interchangeable with the

Model-A or Model-B valve cartridges.


Caution: Valve repair should only be performed by qualified maintenance personnel. Contact United States Plastic Corp ® should further information be required.

Title: Installation and Maintenance Instructions Nibco ® True Union Style Ball Valves
Description: Assembly and maintenance information.
Published: 6/3/2008
Last Edited: 9/18/2013
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