Pentair 178746Z union diamond sealPentair Genuine OEM Union Diamond Seal, 178746Z In stock$1099
Pentair 178746Z union diamond seal
Shop all Pentair

Pentair Genuine OEM Union Diamond Seal, 178746Z

Ask a questionMPN 178746Z
$1099
In stock
Get volume pricing Request a quote

30 day returns · Easy, with prepaid labels provided

Quick overview

  • Genuine Pentair part Factory number 178746Z, not an aftermarket ring.
  • Diamond profile seal The diamond section seats in the union groove, which is why a round o-ring is not a substitute.
  • Clean and Clear RP Listed on the parts breakdown for the Pentair Clean and Clear RP cartridge filter.
  • Stops a weeping union A union that drips after being tightened is nearly always a hardened or nicked seal.
  • Cheap insurance Worth replacing any time the union is broken open for filter service.
  • Part number 178746Z UPC 788379852573, for matching against the seal you are replacing.
Full description and specifications ↓

Need a hand?

Bilingual support from pool professionals.
(888) 751-8084CallChat with a techChatEmail usEmail

Send us a message

A pool professional will get back to you, usually the same business day.

About Pentair Genuine OEM Union Diamond Seal, 178746Z, SKU PAC-051-1787. We will include it with your message.

We use your details to answer this message and nothing else.

Frequently bought together

Current item Pentair Genuine OEM Union Diamond Seal, 178746Z
Pentair

Genuine OEM Union Diamond Seal, 178746Z

$1099
Pentair Genuine OEM High Flow Manual Air Relief Valve, 98209800
Pentair

Genuine OEM High Flow Manual Air Relief Valve, 98209800

$3899
Pentair Genuine OEM Clamp Kit with Tension Control, 190003
Pentair

Genuine OEM Clamp Kit with Tension Control, 190003

$30199
Pentair 150 sq ft and 200 sq ft Clean & Clear Replacement Tank Lid, 178546Z
Pentair

150 sq ft and 200 sq ft Clean & Clear Replacement Tank Lid, 178546Z

$14799
Pentair OEM Tank O-Ring 20-7/8" ID (7/16" Thick), 39010200Z
Pentair

OEM Tank O-Ring 20-7/8" ID (7/16" Thick), 39010200Z

$6099
Pentair Genuine OEM 1-1/2 in. Drain Cap Plug, 190030Z
Pentair

Genuine OEM 1-1/2 in. Drain Cap Plug, 190030Z

$3599
Pentair Genuine OEM Tank Bottom Assembly, Clean & Clear Plus, 178578
Pentair

Genuine OEM Tank Bottom Assembly, Clean & Clear Plus, 178578

$51899
Subtotal

Similar products

Other products people compare with this one.

Pentair 071426Z rubber union o-ring Pentair Genuine OEM Replacement Union O-Ring, 071426Z$599 Pentair 191474Z drain plug o-ring for Clean and Clear Plus filters Pentair Genuine OEM Drain Plug O-Ring for Clean and Clear Plus, 191474Z$599 Pentair 190058 pool filter pressure gauge with indicator Pentair Genuine OEM Pressure Gauge with Indicator, 190058$1499 Pentair 192320 upper bulkhead O-Ring, size 2-137 Buna N Pentair Genuine OEM Bulkhead O-Ring, 192320$899 Pentair 178616 genuine OEM metal compression spring for pool filters Pentair Genuine OEM Compression Spring, 178616$1299 Pentair 39104500 union nut C clip Pentair Union Nut "C" Clip, 39104500$899 Pentair 87300400Z tank body o-ring for Clean and Clear and Predator filters Pentair Tank Body O-Ring, Clean and Clear, 87300400Z$1599 Pentair 86006900 bulkhead o-ring, upper and lower Pentair O-Ring, Bulkhead Upper and Lower, 86006900$999 Pentair 51005000 drain cap fitting o-ring Pentair O-Ring Drain Cap Fitting, 51005000$799 Pentair Housing O-Ring for Predator II Dynamic Leaf Traps | R172223 Pentair Housing O-Ring for Predator II Dynamic Leaf Traps | R172223$1099
Pentair 86300500 black rubber drain cap gasket for Clean & Clear, Predator and Warrior filters Pentair Drain Cap Gasket for Clean & Clear, Clean & Clear Plus, Predator and Warrior Filters Before 11/98, 86300500$1499 Pentair 271096 bulkhead union kit, 1-1/2 inch and 2 inch, white Pentair Genuine OEM Bulkhead Union Kit, 1-1/2" and 2", White, 271096$5399 Pentair 178733Z genuine OEM threaded half union kit Pentair Genuine OEM Threaded Half Union Kit, 178733Z$5899 Pentair 190106Z EasyClean replacement air bleeder Pentair Genuine OEM EasyClean Replacement Air Bleeder, 190106Z$3299 Pentair 170030 air bleed tube assembly for the 240 sq ft Clean and Clear Plus cartridge filter Pentair Genuine OEM Air Bleed Tube Assembly, 240 sq ft, 170030$4799 Pentair 170028 air bleed tube assembly for Clean and Clear Plus 420 filter Pentair Genuine OEM Air Bleed Tube Assembly 420 SQFT, 170028$4799 Pentair 178583 air bleed tube assembly for Clean and Clear 520 and Quad DE 100 filters Pentair Genuine OEM Air Bleed Tube Assembly 520 SQFT, 178583$5099 Pentair 192019 genuine OEM metal drain plug wrench Pentair Genuine OEM Drain Plug Wrench, 192019$5199 Pentair 170040 bottom manifold for Clean and Clear Plus cartridge filter Pentair Genuine OEM Bottom Manifold for Clean and Clear Plus, 170040$6199 Pentair 270100Z valve adapter kit, 2 in by 2.5 in black slip bulkhead Pentair Genuine OEM Valve Adapter Kit 2" Clean and Clear Plus, 270100Z$6399

Product details

The Pentair 178746Z is the union diamond seal, the sealing ring that sits in the groove of a Pentair filter union. It is the genuine Pentair part and it appears on the Clean and Clear RP cartridge filter parts breakdown.

Why the profile matters

The seal has a diamond section rather than a round one, which is what lets it seat in the union groove and hold under the load of the union nut. A standard o-ring of similar size will sit in the groove but will not seal the same way, which is why unions patched with the wrong ring keep weeping.

When to fit one

Replace it any time the union is opened for filter service, and any time a joint drips after the nut has been tightened. Kill the pump, relieve pressure at the air bleed and open the union before working on the seal.

Specifications
Brand Pentair
Manufacturer part number 178746Z
UPC 788379852573
Type Union diamond seal
Profile Diamond section
Listed for Pentair Clean and Clear RP cartridge filter unions
Shipping weight 0.02 lb
Ships Parcel

Request a quote

Need a volume price, a freight quote, or pricing in writing before you order? We reply the same business day.

Request a quote

From Pentair

Your trusted source for all things pool. Pentair

Pentair equipment

Pentair SuperFlo VS 1.5 HP Variable Speed Pool Pump, EC-342001 Pentair MasterTemp 400 Natural Gas Pool Heater, EC-462028 Pentair Clean & Clear Plus 420 sq ft Cartridge Pool Filter, EC-160301 Pentair IntelliConnect Control & Monitoring System with Wi-Fi, EC-523317
Shop Pentair equipment

Genuine Pentair parts

Pentair Genuine OEM Seal Kit for WhisperFlo and IntelliFlo Pool Pumps, 356198 Pentair Genuine OEM High Flow Manual Air Relief Valve, 98209800 Pentair Genuine OEM FNS Plus Element Assembly Complete, 48 Sq Ft, 59023400 Pentair Genuine OEM MasterTemp/Max-E-Therm 6-Button Control Board Kit, 461105Z
Shop Pentair parts
Pool lighting: a backyard pool and spa lit in blue and green at nightPool water treatment: three people floating on rings in clear blue water, seen from abovePool cleaners: a toddler in flower sunglasses laughing in a yellow ring, held by her mother
Pentair makes pumps, filters, heaters, salt chlorinators, cleaners, lighting and automation for pools and spas.Shop all Pentair

Customer reviews

More from Pentair

Pentair SuperFlo VS EC-342001 1.5 HP variable speed pool pump, front view Pentair SuperFlo VS 1.5 HP Variable Speed Pool Pump, EC-342001$1,48900 Pentair SuperFlo EC-348190 single speed pool pump, 1 HP, 115/230V Pentair SuperFlo 1 HP Single Speed Pool Pump, 115/230V, EC-3481905.0 (1) $74800 Pentair WhisperFlo VS EC-011533 2.6 THP variable speed pool pump, top view Pentair WhisperFlo VS 2.6 THP Variable Speed Pool Pump, 115/208-230V, EC-011533$1,79900 Pentair 262506 HiFlow 1.5 in. six way clamp style multiport valve Pentair Genuine OEM HiFlow Valve 1.5 in. 6-Way Clamp Style, 262506$20399 Pentair EC-520556 IntelliChlor 110/220V power center Pentair 110/220V IntelliChlor Salt Chlorine Generator Power Center, EC-520556$79900 Web Price Pentair 523769 IntelliChlor Plus and LT replacement sensor board Pentair IntelliChlor Plus and LT Replacement Sensor Board, 523769$39299 Pentair 350305S 3.2 kW 10 pole variable speed motor for IntelliFloXF and IntelliFlo 2 VST pumps Pentair 3.2 kW IntelliFloXF VSF, VSF, VS+SVRS, i1, i2 Motor, 350305S$78199 Pentair 523735-EC IntelliChlor Plus40 salt chlorine generator cell Pentair IntelliChlor Plus40 Salt Chlorine Generator Replacement Cell, 40,000 Gallons, 523735-EC$1,81900 Web Price Pentair Rainbow 320 in-line chlorinator R171096, front view Pentair Rainbow 320 In-Line Chlorinator, R171096$14499 Pentair 190003 tank clamp kit with tension control for Clean and Clear Plus, FNS Plus and Quad DE filters Pentair Genuine OEM Clamp Kit with Tension Control, 190003$30199
Pentair IntelliChlor LT25 salt chlorine generator cell 523747-EC Pentair IntelliChlor LT25 Salt Chlorine Generator Cell, 25,000 Gallons, 523747-EC$1,14900 Pentair IntelliFlo VS+SVRS variable speed pool pump, EC-011057 Pentair IntelliFlo VS+SVRS Variable Speed Pool Pump, EC-011057$2,39900 Pentair 170145 cartridge pack for Sta-Rite System 3 S7M120, inner and outer cartridges Sta-Rite 170145 System 3 S7M120 Large and Small Cartridge Set, 25021-0200S and 25022-0201S$46499 Pentair 261055 SM-20-3 2 in. side mount multiport valve kit, front view Pentair 2 in. Multiport Valve Kit for Side Mount Sand Filters, SM-20-3, 261055$29999 Pentair 523770 IntelliChlor Plus replacement controller (HMI), black Pentair IntelliChlor Plus Controller Replacement (HMI), Black, 523770$38399 Pentair 261152 SM20-2 2 in. side mount multiport valve kit for DE filters Pentair 2" Valve Kit Multiport, Side Mount DE Filters SM20-2, 261152$29799 Pentair 357149 WhisperFlo and IntelliFlo volute housing replacement kit, front view Pentair WhisperFlo and IntelliFlo Volute Housing Replacement Kit, 357149$28799 Pentair MicroBrite Color LED pool light EC-620425, 12 volt, 14 watt, with 100 ft cord Pentair MicroBrite Color LED Pool Light 12 Volt, 14 Watt with 100' Cord, EC-620425$61900 Pentair 59023400 FNS Plus 48 sq ft complete DE grid assembly Pentair Genuine OEM FNS Plus Element Assembly Complete, 48 Sq Ft, 59023400$39399 Pentair Amerlite EC-602128 500W 120V inground pool light with stainless steel facering Pentair Amerlite Pool Light for Inground Pools with Stainless Steel Facering, 500W 120V 50' Cord, EC-602128$43900 Web Price

Questions and answers

What people ask about this product, answered by our pool techs.

Can I use a standard o-ring instead?
No. The seal has a diamond section made to sit in the union groove, and a round o-ring of the same diameter will not seat the same way.
Which filter is it listed for?
It appears on the Pentair Clean and Clear RP cartridge filter parts breakdown.
My union drips even when I tighten it hard. Is this the fix?
Usually. Overtightening a union to stop a drip damages the fitting. If the seal is hard, flattened or nicked, replace it rather than crank down further.
Should I lubricate it?
A thin film of pool grade silicone lubricant helps the seal seat and makes the union easier to open next time. Petroleum grease attacks the material and should be kept away.
Ask your own question