Champion Big-Lock Plug Cap - Plain and 1/2 in FNPT Ported (73mm to 220mm)

A Champion Big-Lock plug cap closes off the end of a grooved aluminum main. It comes in two forms: plain, which simply terminates the run, and ported, with a 1/2 in female NPT tapping in the face.

The ported version is the more useful of the two more often than people expect. That 1/2 in port is where a pressure gauge goes at the far end of a main, or a drain at the bottom of a riser, or a future take-off that costs nothing to leave in place today.

Choose your size and port from the dropdowns above.

Model Selection Chart

A plug cap seats on a grooved pipe end, so it needs a straight union coupling to hold it on. Order one per cap.

Spend the Extra and Take the Port

The ported cap costs between $19 and $67 more than the plain one at list depending on size. For that you get a permanent 1/2 in NPT tapping at the end of the run, which is worth having for three reasons.

• A gauge at the far end of the main. The pressure at the compressor tells you almost nothing. The gap between the compressor gauge and a gauge at the end of the header is your real distribution loss, and it is invisible without this.
• A drain at a low point. If the capped end is the bottom of a riser or the low point of a pitched main, that is exactly where condensate collects, and the port takes a drain valve directly.
• A future take-off. Plug it today, use it in three years when something gets added at that end of the building.

Plan the Main to Grow

Nobody has ever regretted leaving a capped stub in a compressed air main. What plants regret is an undersized header with nowhere to tie in, because adding a branch later means isolating, draining, cutting and re-grooving a live main.

When we lay out a Big-Lock system we normally put a capped tee wherever the floor plan looks likely to change: the end of a bay, the edge of an area earmarked for a cell, the point where a second compressor or receiver might land. A plug cap is $65 to $207. A shutdown to cut into a 6 in header is not.

Shared Technical Specifications

Specification note. Champion's price list publishes description, part number and list price for the Big-Lock range and nothing else: no pressure rating, no temperature band, no weights and no dimensions, and we have not found a Big-Lock datasheet that supplies them. This listing states only what Champion publishes. Ask us and we will source anything further from the factory before you order.

Ideal Applications

Terminating a plant main at the far wall, capping the spare leg of a junction tee left in for future expansion, closing a stub during a phased install so the rest of the plant can run, blanking a branch taken out of service, and, in the ported version, fitting a gauge or a drain exactly where the system needs one.

Building a Complete Big-Lock System

• Big-Lock aluminum pipe, 73mm to 273mm
• Straight union couplings, one per plug cap
• Junction tees and reduction tees, the usual thing a capped stub hangs off
• 90 and 45 degree elbows and street elbows
• Threaded adapters and reducers
• Quick-Lock 2.5 in liquid filled gauges, which fit the 1/2 in port on the ported caps

Ordering Notes

• All Big-Lock products and accessories are NO CANCEL / NO RETURN, per Champion's current price list.
• Freight: freight collect from Huntersville, NC 28078 or Las Vegas, NV 89113.
• Shipping weights: Champion publishes no weight for any Big-Lock fitting, so no catalog weight is carried on these variants.
• Photography: Champion publishes no photograph of the Big-Lock plug caps, so this listing is deliberately shown without an image rather than with a stand-in from another manufacturer's grooved range.

Why Buy from Air Compressor Store

Air Compressor Store is an authorized Champion Pneumatic distributor. We will tell you where to leave capped stubs before the system goes in rather than after, and which of them should be ported. Send us the floor plan and we will quote the whole bill of material at no charge.

Frequently Asked Questions

Does the cap include a coupling?

No. The plug cap seats on a grooved pipe end and a straight union coupling holds it there. Order one coupling per cap. In the Big-Lock range only the elbows and tees include their couplings.

Can I remove a cap later to extend the run?

Yes, and that is the point of leaving one. Isolate and depressurize the section, undo the coupling bolts, pull the cap off and carry on with pipe. No cutting, no re-grooving, no hot work. Inspect the gasket before it goes back into service.

Is there a 273mm plug cap?

Not in the current price list. The 273mm Big-Lock range is largely consult factory. Call or email and we will get it quoted.

What goes in the 1/2 in port?

Most often a liquid filled pressure gauge, a drain valve, or a plug until you need it. Champion's 2.5 in liquid filled gauges in the Quick-Lock accessory range take a 1/2 in male NPT and fit straight in.

Can I pressure test with caps fitted?

Yes, and that is the normal way to commission a main before the branches are finished. Bring the pressure up in stages, inspect the joints at each step and hold at working pressure before signing it off. Champion publishes a 15 psig incremental procedure for Quick-Lock; apply the same discipline here and ask us if you want the Big-Lock figures confirmed by the factory first.

Why is the 220mm cap so much more than the 168mm?

$207 against $112 at list. An 8 in cap is a considerably heavier casting and has to hold full system pressure against the whole bore area. Both are shown at Champion's list price.