Home » Precast Connector Resources »
A compression connector seals because it was cast in perpendicular and uniform to the center of the pipe. That is set at the plant, on the mandrel, before any concrete is poured.
Experience has shown that successful performance of this product depends on proper plant installation, as well as the backfill and the care in the field installation of the manhole or wastewater structure and connecting pipes.
These are A-LOK’s mandrel mounting instructions, in A-LOK’s words. The field steps for the pipe are on the compression installation page.
1. Check the mandrel offset
Remove nuts and separate mandrel halves. Measure the mandrel offset dimension at 3-9 and 6-12 to be sure it matches the connector I.D. on the A-LOK Dimensional Data Sheet.
Oil or wax outside of mandrel (Not the connector)
2. Set the connector: the nub faces out
Place connector nose against the mandrel offset on the outside half with the nub (the side with the white stripe) of the Premium connector facing away from the center of the mandrel.
Roll connector nose against the mandrel offset on the outside half. The nub on the A-LOK Premium connector should be down against the outside mandrel half.
An A-LOK X-CEL connector does not have a front and back. An A-LOK Premium Connector has a side with a nub (marked with a white stripe) that must be facing away from the center of the mandrel.
Note: A-LOK Mandrel Installation Grips are recommended to hold the connector in place which reduces set-up labor while promoting proper connector installation.
3. Close the mandrel and check the inspection holes
Set the inside half of the mandrel on top and tighten nuts.
Check all inspection holes to insure the connector is tight about the offset. The embedded “T” of the connector should be perpendicular to the centerline of the mandrel.
4. Mandrels size 600 and above
Note: Mandrels size 600 and above - Flat spot must be placed on the outside towards the bottom of the structure to ensure pipe will be centered in connector during installation.
The flat spot is also the reference for finding the subgrade in the field; the compression installation page has that step.
5. Z-LOK STM on the two-piece mandrel
Stretch gasket over outside mandrel half. Force gasket down inside mandrel before installing in form. Use coil nut to tighten gasket and mandrels together.
Pull connector over one-piece Wedge Knockout Hole Former as shown.
6. Questions in the plant
If a connector will not seat on the mandrel, or an inspection hole shows a gap, call A-LOK before the pour. Any questions regarding installation, call 1-800-822-2565.
Frequently asked questions
Which way does the nub on a PREMIUM connector face on the mandrel?
An A-LOK X-CEL connector does not have a front and back. An A-LOK Premium Connector has a side with a nub (marked with a white stripe) that must be facing away from the center of the mandrel. Place connector nose against the mandrel offset on the outside half with the nub (the side with the white stripe) of the Premium connector facing away from the center of the mandrel.
How do you check that a connector is seated on the mandrel?
Check all inspection holes to insure the connector is tight about the offset. The embedded “T” of the connector should be perpendicular to the centerline of the mandrel.
Where does the flat spot go on mandrels size 600 and above?
Note: Mandrels size 600 and above - Flat spot must be placed on the outside towards the bottom of the structure to ensure pipe will be centered in connector during installation.
Questions before the pour?
Tell us the connector, the mandrel, the pipe type, and the pipe dimensions and we will confirm the setup. The field clamp steps for boot connectors are on the boot installation page.