Apollo Backflow Repair Kit | Pick The Exact Kit Fast

Backflow devices are quiet until they are not. One day you spot a slow drip at the relief port, a wet spot under the bonnet, or a test report that didn’t pass. The fix is not a whole new assembly. It’s the small wear parts that do the sealing work.

An apollo backflow repair kit is a “refresh” pack. You replace the rubber pieces and o-rings that age, flatten, or pick up grit. Done right, you stop nuisance leaks, restore shutoff inside the checks, and avoid repeat call-backs.

What A Repair Kit Fixes And What It Can’t

Most failures come from simple stuff: debris on a sealing surface, an o-ring that has taken a set, or a rubber disc that is nicked. Repair kits target that layer of parts because it is the layer that moves and seals each time the device cycles.

Still, a kit is not magic. If the body is cracked, if threads are stripped, or if a check module is damaged beyond cleaning, you may need a module swap or a full valve replacement. The goal is to know which bucket you are in before you order parts.

Signs You’re In “Rubber Parts” Territory

• Intermittent Drips — Water shows up after irrigation runs, then stops once pressure settles.
• Slow Weeping At An O-Ring Joint — A cap, lid, or bonnet area stays damp even when the device is not flowing.
• Failing By A Hair — Your tester notes a check that is close but not sealing cleanly.
• Grit After Water Work — A nearby main break or valve replacement stirred up sand and scale.

Signs You Should Plan For Bigger Parts

• Visible Body Damage — Cracks, freeze splits, or deep pitting on the seating surfaces.
• Repeated Failure After Cleaning — The same check fails right after a careful rebuild.
• Badly Worn Moving Pieces — Bent springs, broken retainers, or a module that won’t slide in straight.

Choosing An Apollo Backflow Repair Kit By Model And Size

This is the part that saves the most time. “Apollo 4A” is a family, not one valve. A pressure vacuum breaker (PVB) uses different parts than a reduced pressure assembly (RP). Even inside the same family, the 1″ size will not share kits with the 2″ size.

Start with the nameplate. Look for the model line (PVB4A, RP4A, RPLF4A, DC4A, and similar) and the nominal size.

Match The Kit To The Failure Point

Most suppliers break kits into categories so you can buy only what you need. For PVBs you’ll see “float and check rubber” kits or “top half” kits. For RP assemblies you’ll see check kits, relief valve kits, or a complete rubber kit.

• Check Rubber Kit — Targets the check sealing surfaces and related o-rings.
• Relief Valve Rubber Kit — Targets the relief valve soft goods and o-rings.
• Complete Rubber Kit — Bundles check and relief valve rubber parts in one box.
• Top Half Kit — On PVBs, replaces the bonnet and float pieces that vent air.

Quick Reference Table For Common Apollo 4A Family Kits

The table below shows kit groupings used in Apollo documentation. Use it as a starting point, then confirm your exact model and size before you buy.

Those kit numbers follow the “size matters” pattern you’ll see across the catalog. In plain terms, the part code changes with size, even when the kit name sounds the same.

What’s Inside A Typical Apollo Kit

When you open the box, you should see small parts in bags. On PVB kits, you’ll often see o-rings plus seat discs. On “top half” kits, you’ll also see the bonnet and float subassemblies because those parts handle the air inlet function.

One thing that surprises first-time buyers is lubricant. Some kits include an o-ring lubricant line item. Apollo manuals call out a supplied lubricant and also note Dow 111 or an equivalent silicone grease for o-rings in certain steps. That’s a clue that dry assembly is not the move. A thin film helps the o-ring seat without twisting.

Parts That Usually Do The Heavy Lifting

• O-Rings — Seal lids, caps, and modules so pressure stays where it belongs.
• Seat Discs — Provide the soft sealing face for check valves or float seats.
• Bonnet And Float Pieces — On PVBs, control venting and shutoff during back-siphon conditions.
• Relief Valve Rubber Parts — On RP assemblies, manage the relief opening point and sealing.

Check Modules Versus Rebuild Parts

Some Apollo assemblies use check modules that slide in as cartridges. In certain maintenance instructions, Apollo notes that check valve modules are not user serviceable, and that failed modules are sold as replacements. Cleaning debris off a module may help, but rebuilding the module itself is not always an option.

Tools And Prep Before You Open Anything

Backflow devices are pressurized fittings. The safest path is slow and tidy: shut off, relieve pressure, then open the unit. Rushing is how you get a face full of water or lose a small spring into gravel.

Set up a clean work surface and keep old parts in order. If you are outdoors, a shallow tray or towel helps keep o-rings from rolling away.

Basic Tools Most Jobs Use

• Adjustable Wrench — For caps, clamps, and fittings.
• Allen Wrenches Or Sockets — Many lids use hex-head hardware.
• Soft Brush — Clears grit without scratching seats.
• Clean Rags — Wipe sealing surfaces and dry parts for inspection.
• Food-Grade Silicone Grease — A light coat on o-rings, matching manufacturer notes.

Shutoff And Pressure Relief Sequence

Most Apollo manuals use the same rhythm: close the downstream shutoff, close the upstream shutoff, then open test cocks to bleed pressure. That order keeps the device from backfeeding as you open it.

• Close Downstream Isolation — Stops flow to the system side.
• Close Upstream Isolation — Stops supply pressure to the device.
• Open Test Cocks — Relieves trapped pressure so lids come off safely.

Repair Steps That Cut Leaks And Pass Testing

Different Apollo assemblies open in different ways, so follow the manual for your exact model. The steps below stay high-level on purpose and it calls out the common “gotchas” that cause leaks after a rebuild.

If you’re working on a PVB (often used on irrigation), you’ll deal with the bonnet and float area plus the check. If you’re on an RP assembly, the relief valve section deserves extra care because that’s where many drips show up.

Clean First, Replace Second

• Rinse Loose Debris — Flush sand and scale off parts so you can see wear marks.
• Inspect Seats Under Light — Look for nicks, dents, or a groove where a disc sits.
• Check O-Ring Grooves — Dirt in the groove can pinch a new o-ring and cause a leak.

Install Rubber Parts Without Twisting

• Use A Thin Grease Film — A light coat on the o-ring helps it slide and seat cleanly.
• Seat Parts Square — Push modules straight in to avoid shaving the o-ring edge.
• Torque Evenly — Tighten bolts or clamps in a cross pattern so lids seat flat.

Relief Valve Work On RP Assemblies

On Apollo RP manuals, the relief valve procedure calls out inspection of the diaphragm, seat disc, o-rings, and stem. If those pieces look worn, replace them with the correct kit parts, then lubricate the stem o-ring and related o-rings per the manual’s lubricant note.

• Keep Springs Controlled — When a plate screw comes out, hold the assembly so the spring doesn’t jump.
• Check The Sensing Hose — A cracked hose can cause odd relief behavior and repeat trips.
• Confirm Full Seating — Seats and cartridges must sit fully down before the clamp is tightened.

Reassemble With A Final Visual Scan

Before you restore pressure, do a quick look for pinched o-rings, leftover grit, and loose test cocks. It takes one minute and saves a full drain-down.

After The Repair: Retesting, Winterizing, And Routine Care

Backflow devices are often regulated. After internal parts are replaced, many areas require a certified test and a documented pass. Plan the test date so the device isn’t left offline.

Also think about the season. PVBs on irrigation lines can freeze. Apollo installation and operation manuals list winterizing steps such as draining through test cocks and placing isolation valves in a half-open position to avoid trapped water.

Pressure-Up Without Drama

• Open Upstream Slowly — Let the assembly fill without slamming the checks.
• Bleed Air At Test Cocks — Close them once flow is steady.
• Open Downstream Last — Restores service after the valve is stable.

Simple Habits That Extend Service Life

• Flush After Line Work — Sediment is the enemy of soft seals.
• Keep The Vault Dry — Standing water speeds corrosion and hides small leaks.
• Store Spare Rubber Sealed — Heat and sunlight age rubber even on the shelf.

Buying Tips That Prevent The Wrong Kit Arriving

Online listings can be messy. Some sellers use “Apollo 4A kit” as a catch-all. Your job is to match three details: model family, size, and kit category. If one is off, the o-rings may not fit or the disc diameter will be wrong.

If you are replacing parts for a PVB4A, the Apollo tables show separate kits for “float and check rubber,” “float and bonnet complete,” and “complete internals.” Those names are close, but the contents differ, so pick the one that matches your symptoms and your test notes.

Checklist Before You Click Buy

• Read The Nameplate — Capture model, size, and any suffix letters.
• Choose The Kit Category — Rubber-only, top-half, or full internals based on what failed.
• Confirm Part Numbers — Match the ordering number to your size range.
• Buy Fresh Rubber — Avoid mystery “old stock” when seals matter.

OEM Versus Aftermarket

Genuine parts reduce guesswork because the rubber hardness and dimensions match the original design. Aftermarket kits can work, but quality varies by seller and batch. If your area is strict about test passes, the safer play is to stick with known part numbers and reputable supply houses.

When you do it right, an apollo backflow repair kit is one of those satisfying fixes. It’s small parts, a clean rebuild, then a dry vault and a clean test report. Keep your notes, snap a photo of the kit label, and the next maintenance cycle gets even easier.

Send us your feedbackTell us what you thought about this post

Name * Email *

Your comment *

Quick check — what is …? *

Send feedback