Davey SpaQuip, Hayward 69mm OD Barrel Union O-Ring - Q5112 - 50mm Nominal

Davey Spa-Quip / Hayward 50mm Barrel Union O-Ring - Q5112 
69mm OD x 5mm Cross Section

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• Physically Stocked, unlike most "drop-shipping" websites.
• Shipped from VIC, NSW, WA, QLD

Davey / Spa-Quip / Spa Power 50mm (nominal) Barrel Union O-Ring measures approx 69mm outside diameter, with a 5mm cross section. Also used on compatible Hayward, Piranha and PoolPower union assemblies.

Replacement sealing O-ring for the face of a 50mm nominal barrel union. This O-ring sits between the union tail and mating union face, with the locking nut holding the connection together. Commonly used on spa pumps, pool pumps, heater tubes, spa controllers, chlorinators and filter multiport valves.

Sold individually. One O-ring supplied. Union nut and tail are not included.

Quick Identification Guide & Dimensions

• Outside Diameter (OD): 69mm
• Cross-Section / Thickness: 5mm
• Inside Diameter (ID): Approximately 59mm when calculated from nominal 69mm OD and 5mm cross-section
• Union Size: 50mm / 2" nominal plumbing size
• Union Pattern: Common Australian Davey / Spa-Quip coarse-thread barrel union style & Hayward unions.
• Davey / Spa-Quip Part Number: Q5112
• Quantity: 1 x O-ring

Important - 50mm does not mean the O-ring measures 50mm. Australian and New Zealand 50mm pressure PVC pipe measures approximately 60-61mm outside diameter. The O-ring is larger because it seals against the union face, not around the outside of the pipe.

Always measure the existing O-ring, or identify the original union assembly, before ordering. Used O-rings can stretch, flatten, harden or distort, resulting in different measurements.

Which O-Ring Do I Actually Need?

• This is the 50mm barrel union face O-ring. It seals between the union tail and the adjoining pump, heater, valve or union body.
• Hayward unions: Some Australian Hayward 50mm union packs contain two different O-rings: one for the standard union tail and another for the threaded tail. This listing is for the standard union tail sealing position, subject to matching dimensions.
• 40mm unions: If you need the smaller O-ring, see our Davey / Spa-Quip 40mm Union O-Ring here.
• Complete 50mm union: If the locking nut or tail is damaged, see our complete Davey / Spa-Quip 50mm Barrel Union here.

Common Symptoms of a Failed Union O-Ring

• Water dripping or weeping from the barrel union face.
• Leak continues even after the union nut has been tightened.
• Existing O-ring has become flat, hard, brittle, glazed or square-edged.
• O-ring has split, perished, swollen or become distorted.
• Union only appears to seal when excessively tightened, risking damage to the plastic locking nut.
• Leaks appear after the union has been disconnected for maintenance or repairs.

Replacing a worn O-ring often resolves a leaking union. However, a cracked nut, distorted union tail, damaged sealing face or incorrectly aligned connection may also cause leaks.

Compatible Davey / Spa-Quip / Spa Power Equipment

Spa Power Control Systems - Heater Tube Unions

• Spa Power SP600 / SP601
• Spa Power SP750
• Spa Power SP800
• Spa Power SP1000
• Spa Power SP1200
• Spa Power SP2000

Used on the matching 50mm heater tube barrel unions fitted to these spa control systems. Earlier and later equipment revisions may use different union assemblies.

Davey / Spa-Quip Pumps

• Spa-Quip Maxi Flow / Maxiflow booster pumps
• Spa-Quip Monster pumps
• Spa-Quip Powerplus pumps using the Q5112-style union
• Davey Silensor SLL300 and SLL400 pumps
• Davey Silensor SLL series using the matching 50mm union
• Davey PowerMaster pumps using compatible 50mm barrel unions
• Davey PowerMaster Eco pumps using compatible 50mm barrel unions

Note: Not every Davey Silensor or PowerMaster pump uses the same union size. Some smaller pumps use 40mm connections, while others use 40/50mm combination unions. Check the actual union and O-ring dimensions.

Davey Chlorinators, Brominators & Filters

• Davey AquaReviva chlorinators
• Davey ChloroMatic EcoSalt MES series
• EcoMatic Compact and EcoMineral chlorinators
• Davey BMSC and CN series chlorinators
• Davey EcoSpa brominators
• Davey FG28, FG32 and FG36 sand filter multiport valves
• Monarch / Davey EcoPure and Reliance MK3 filter multiport valves using the M8200 assembly

These applications use the Davey / Spa-Quip 50mm union O-ring pattern. Check the relevant sealing position and original assembly before purchasing.

Davey / Spa-Quip Associated Part Numbers

• Q5112: Original 50mm union O-ring reference
• Q5112-1: Supplier reference used for the 50mm union O-ring
• PL-BS5112: Additional trade catalogue reference
• Q5114BK-SET: Complete union kit containing Q5112 O-ring, Q5114BK-10 tail and Q5113BK locking ring
• 48722 / 48722B / 48722BSP: Associated Davey 50mm union assembly references

The complete union assembly numbers are included for identification and are not individual O-ring part numbers.

Piranha Spa Pumps

Also used on Piranha spa jet pumps and two-speed pumps fitted with the compatible 50mm coarse-thread barrel union pattern.

Some Piranha pumps use different union assemblies. Compare your existing O-ring and union face before ordering.

Hayward 50mm Barrel Unions

Similar 50mm barrel unions were widely used on older Australian Hayward pumps, multiport valves and sand filters.

Hayward's Australian distribution and parts history includes Clevaquip, the Melbourne-based pool equipment distributor in which Hayward acquired a majority interest in 2011. As a result, older Australian Hayward equipment may use legacy Clevaquip-style part references such as UN5050 rather than the usual Hayward SPX-style numbering.

Hayward Pumps

• Hayward Super Pump II, where fitted with the matching Australian 50mm union assembly
• Other older Hayward pumps using the corresponding 50mm barrel union

Hayward Multiport Valves

• SP0715 - 50mm
• SP0716 - 50mm
• SP0715XR50 - 2" valve configuration

Hayward Sand Filters

• S244T2C
• S270T2C
• S310T2C
• S360T2C
• S244S
• S310S
• S360

Hayward DE Filters

• DE2420
• DE3620
• DE4820
• DE6020
• DE7220

Hayward filter compatibility: The filter model alone is not sufficient to identify the O-ring. Check that the filter uses the applicable 50mm multiport valve or union assembly, including SP0715XR50 where relevant.

Hayward Associated Union Part Numbers

• UN5050 - Legacy Australian / Clevaquip-style union reference
• SP50RPAUUNPAK
• 20-SP50RPAUUNPAK
• 20-SP50RPAUUNPK
• SP50RPT - Single union reference
• SP24X50AUUNPAK - Three-union pack
• 20-SP24X50AUUNPAK
• HAY-56-91003 - Trade catalogue reference

Important - Hayward union O-rings: Hayward SP50RPAUUNPAK and SP24X50AUUNPAK union packs include separate threaded-tail and standard union-tail O-rings. They are different sealing positions and should not be confused.

The above numbers identify associated Hayward union assemblies, not confirmed direct cross-reference part numbers for Davey Q5112. This O-ring is intended for the matching standard union-tail sealing position only. Confirm the original O-ring dimensions and sealing face before ordering.

PoolPower Chlorinator Cells

Also used on some older PoolPower chlorinator cells fitted with the corresponding 50mm barrel union.

Important: On some PoolPower cells, this O-ring is used on one end only. The opposite end may have a different seal or connection. Check before ordering.

Installation & Fitting Tips

1. Isolate the equipment: Switch off the pump or spa system, isolate the power supply as appropriate and relieve water pressure before opening the union.
2. Remove the old O-ring: Inspect the seal for flattening, cracking, swelling or hardening.
3. Clean the sealing faces: Remove dirt, grit, debris and old sealant from the union tail and mating face.
4. Inspect the plastic components: Check the union nut, tail and mating body for cracks, warping, scoring or damage.
5. Fit the new O-ring: Install without stretching, twisting or pinching it. Fit dry where specified by the manufacturer, or use a small amount of compatible silicone-based O-ring lubricant where permitted.
6. Reconnect the union: Align the mating faces correctly and tighten the union nut according to the manufacturer's instructions. These unions generally seal through O-ring compression, not excessive thread tension.
7. Check for leaks: Restore operation and inspect the connection under normal operating conditions.

Avoid petroleum-based grease or Vaseline. Petroleum products can damage or swell some rubber sealing materials. Use only lubricants compatible with the O-ring material and equipment manufacturer's instructions.

Do not overtighten plastic union nuts. Excessive force can crack the locking ring or damage the sealing faces. If a new O-ring does not seal with correct assembly, investigate the mating surfaces and union components rather than continually tightening the nut.

Important Compatibility Information

• Coarse-thread versus other union patterns: More than one 50mm barrel union design is used in Australia. The nominal plumbing size alone does not establish O-ring compatibility.
• Thread style is not an O-ring measurement: Compare the sealing face, O-ring diameter and cross-section, not only the thread pitch.
• American-style spa pump unions: Many Aqua-Flo, LX, SpaNET, Waterway and other jet pumps use a different 2" pump union arrangement with different seals. Do not assume this Davey O-ring will fit them.
• Old or distorted O-rings: A worn seal may measure differently from a new one. Where possible, identify the union from its original part number.
• Model variations: Manufacturers may change unions or fittings between production runs. Always check the actual connection fitted to your equipment.

For alternative spa pump union designs, see our Aqua-Flo / LX / SpaNET / Waterway 50mm pump union range here.

Not Sure Which Union O-Ring You Need?

We stock a range of pump, heater and spa barrel union O-rings. Many look similar but have different diameters, thicknesses and sealing profiles.

Before ordering, compare the original O-ring dimensions, union sealing face and equipment model. If you are unsure, contact us with clear photographs and measurements so we can help identify a suitable replacement.

Also Known As - Alternative Names & Search Terms

Spa-Quip 50mm O-ring, SpaQuip union O-ring, Davey Q5112, Q5112-1 O-ring, Spa Power 601 O-ring, SP600 O-ring, SP800 O-ring, SP1000 O-ring, SP1200 O-ring, SP2000 O-ring, Maxiflow union O-ring, Maxi Flow pump union seal, Silensor SLL O-ring, PowerMaster union O-ring, Monster pump union seal, Powerplus pump O-ring, Piranha pump union O-ring, heater tube union O-ring.

50mm barrel union O-ring, 2 inch union O-ring, 69mm OD O-ring, 5mm thick O-ring, 50mm pump union seal, 50mm heater union gasket, barrel union face seal, Hayward UN5050 O-ring, Hayward SP0715 union O-ring, Hayward SP0716 union O-ring, Super Pump II union O-ring, SP50RPAUUNPAK O-ring, SP24X50AUUNPAK O-ring, Clevaquip union O-ring, PoolPower chlorinator cell O-ring, coarse-thread union O-ring.