Waterco Trimline MkIII Cartridge Filter Tank Lid O-Ring - 214mm - C25, C50, C75, CC50, CC75, CC100 - 62026
Waterco Trimline MkIII Cartridge Filter Tank Lid O-Ring - 214mm - C25, C50, C75, CC50, CC75, CC100 - 62026 is temporarily out of stock and will ship as soon as it's available.
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Don't Guess - Ask Us!
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Waterco Trimline MkIII Cartridge Filter Tank Lid O-Ring - 214mm - C...
Waterco Trimline MkIII Cartridge Filter Tank Lid O-Ring - 214mm - C25, C50, C75, CC50, CC75, CC100 - 62026 is temporarily out of stock and will ship as soon as it's available.
Waterco Trimline MkIII Cartridge Filter Tank Lid O-Ring — 214mm
Genuine Waterco tank lid o-ring, part number 62026, sized 214mm to match the MkIII lid. This is the seal between the lid and the filter body on Trimline MkIII cartridge filters. It is the part to replace when water weeps or sprays from around the lid, or when the lid will not hold pressure after servicing.
Listed as item 4 in Waterco's Australian Trimline cartridge filter manual.
Specifications
| Part Number | 62026 |
| Manufacturer Description | Lid O-Ring MK3 |
| Size | 214mm — matches the MkIII lid outside diameter |
| Brand | Waterco |
| Diagram Reference | Item 4 — Trimline cartridge filter manual |
| Barcode | 9314800098794 |
| Quantity Per Filter | 1 |
Fits
Waterco Trimline MkIII cartridge filters:
- Trimline C25, C50, C75
- Trimline CC50, CC75, CC100, CC150
Waterco also list 62026 as the 8" top lid o-ring for their side mount sand filters, so the same seal is used on some Micron and SM series tanks.
MkII or MkIII? Measure the Lid
This o-ring is specified for the MkIII only, and the two versions are not interchangeable. The quickest way to tell them apart is the lid diameter:
- MkIII lid — 214mm outside diameter — lid o-ring 62026 (this part)
- MkII lid — 221mm outside diameter — lid o-ring 62021
If you are not certain which version you have, send us a photo of the filter and a measurement across the lid before ordering.
Fitting
Shut the pump down and release tank pressure at the air bleed before removing the lid. Clean the groove and the sealing face, then fit the o-ring and give it a light smear of silicone-based o-ring lubricant. Do not use petroleum grease — it swells and degrades the rubber. Seat the o-ring fully before refitting the lid and lock ring, and re-pressurise slowly while checking for leaks.
Related Trimline MkIII Parts
- 620260 — MkIII lid o-ring in Viton, for salt and high-sanitiser installs
- 62025 — MkIII lid, supplied with o-ring
- 62024BLK — Lid lock ring, 52mm high
- 620221 — Air release valve
- 122257BLK — 40/50mm half union, MkIII post-2001
Manufacturer Manuals, Diagrams & Part Numbers
Need exploded views, spare part numbers, diagrams, or more product information? See Waterco's Trimline Cartridge Filter manual.
Important Before Ordering: Please ensure you order correctly. Confirm this product is suitable before ordering. Use the manual above, seek professional assistance, or contact us with photos of your existing part, model details, serial numbers, and any labels.
As with all products, these must be diagnosed and fitted by a qualified and experienced person.
To the layperson, plumbing sizes and their names can be confusing due to the nominal sizes and naming conventions used.
This is not something we made up. Plumbers and manufacturers have used nominal (meaning ‘by name only’) sizing for decades.
Simply put, in plumbing, named sizes are often not the actual measurements of the pipe, fitting, or part. A PVC pipe called “50mm” or “2"” does not measure 50 mm anywhere. Instead, it follows nominal sizing, an internationally-standardised naming system.
Almost all fittings we use in the pool & spa industry use “pressure PVC” pipe & fittings. Do not confuse with “DWV” or other pipe & fittings and their names and sizes.
Use the Outside Diameter (OD) to check your pipe against fittings. Below is a quick reference for common spa & pool pipe sizes:
| Imperial Name | Metric Name | Pipe Diameter (OD) |
|---|---|---|
| 1/2" | 15mm | ~21.2–21.5 mm |
| 3/4" | 20mm | ~26.6–26.9 mm |
| 1" | 25 mm | ~33.4–33.7 mm |
| 1.5" | 40 mm | ~48.1–48.4 mm |
| 2" | 50 mm | ~60.2–60.8 mm |
| 2.5" | 65 mm | ~75.2–75.5 mm |
To reiterate, these are nominal sizes and are designed to fit matching fittings — not to measure what their name suggests. These are based on PVC Pressure Pipe AS/NZ 1477 Dimensions1.
- º Internal diameters vary slightly by manufacturer and class.
- 1 Not all pool/spa fittings match these dimensions exactly. Some do not follow Australian or international standards. Chinese spas may use proprietary fittings.
Understanding Plumbing Sizes & Nominal Measurements
Plumbing sizes can be confusing. PVC and many other pipe systems use nominal sizes—the size is a name, not the exact measured dimension. This convention is used across most pool and spa systems and other plumbing areas so that pipes and fittings remain compatible.
Why pipe sizes don’t match the measurements
The Nominal Pipe Size (NPS) system standardises pipe dimensions so that pipes, fittings, valves, and accessories interoperate.
Plumbers work with these nominal names every day, but DIYers can be tripped up if they try to match by a tape-measure alone.
How to Measure Pipe Correctly
-
Pipe size is identified by:
- The pipe’s Outside Diameter (OD).
- The fitting’s Inside Diameter (ID) (socket opening).
- Pipe Class / Schedule (e.g., Class 9, 12, 18 or Sch 40) relates to wall thickness and therefore the Internal Diameter (ID) and pressure rating.
- The outside diameter of a fitting is not useful (wall thickness varies by manufacturer).
Hose & Tube Dimensions
Common flexible hose sizes used in pool/spa systems (approximate IDs).
| Imperial Name | Metric Name | Inside Diameter (ID) |
|---|---|---|
| 3/8" | 9–10 mm | ~9 mm |
| 3/4" | 19 mm | ~19 mm |
BSP – British Standard Pipe Thread Sizes
BSP thread names are also nominal. The thread OD will not equal the nominal name.
| BSP Thread Size Naming | Outside Diameter (mm / inch) | TPI |
|---|---|---|
| 1/16" BSP | 7.7 mm / 0.304" | 28 |
| 1/8" BSP | 9.7 mm / 0.383" | 28 |
| 1/4" BSP | 13.16 mm / 0.518" | 19 |
| 3/8" BSP | 16.66 mm / 0.656" | 19 |
| 1/2" BSP / 15 mm | 20.99 mm / 0.825" | 14 |
| 5/8" BSP | 22.99 mm / 0.902" | 14 |
| 3/4" BSP / 20 mm | 26.44 mm / 1.041" | 14 |
| 7/8" BSP | 30.20 mm / 1.189" | 14 |
| 1" BSP / 25 mm | 33.25 mm / 1.309" | 11 |
| 1-1/4" BSP | 41.91 mm / 1.650" | 11 |
| 1-1/2" BSP / 40 mm | 47.80 mm / 1.882" | 11 |
| 2" BSP / 50 mm | 59.61 mm / 2.347" | 11 |
| 2-1/4" BSP | 65.71 mm / 2.587" | 11 |
| 2-1/2" BSP | 75.18 mm / 2.960" | 11 |
| 3" BSP | 87.88 mm / 3.460" | 11 |
| 4" BSP | 113.03 mm / 4.450" | 11 |
| 5" BSP | 138.43 mm / 5.450" | 11 |
| 6" BSP | 163.83 mm / 6.450" | 11 |
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