Astralpool / Hurlcon - Len Gordon Pressure Switch
Astralpool / Hurlcon - Len Gordon Pressure Switch is temporarily out of stock and will ship as soon as it's available.
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Astralpool / Hurlcon - Len Gordon Pressure Switch
Astralpool / Hurlcon - Len Gordon Pressure Switch is temporarily out of stock and will ship as soon as it's available.
Astralpool / Hurlcon - Len Gordon Pressure Switch for Gas Heaters
OEM Genuine LG/AI Water Pressure Switch (Flow Switch) for all Hurlcon, Astralpool HX, JX, MX, HiNRG, Viron, ICI gas heaters. Current version supersedes all older versions with Stainless Steel thread (that were known to get blocked by rust easily).
- Physically Stocked, unlike most "drop-shipping" websites.
- Shipped from VIC, NSW, WA, QLD
Allied Innovations / Len Gordon. Exactly the pressure switch found in Astralpool & Hurlcon heaters, but at a great price. Note that these have been discontinued by the manufacturer in the USA, so we bought all the remaining stock available.
Suits Astralpool, Hurlcon, Raypak, INSNRG, Pentair and many gas heaters that use the same 1/8" NPT thread.
Adjustable 1-5 PSI / 7-35kPa, with 1/8" NPT thread. Originally had stainless thread.
Installation Instructions:
- Ensure female thread of socket is clean and in good condition.
- Use small amount of thread tape or suitable thread sealant on male thread.
- Too much tape can damage both switch & socket
- Gently screw in by hand, ensuring not to cross-thread, or over-tighten*.
- Adjust pressure switch as per manufacturer's instructions. Simply slide the black locking toggle upwards to allow adjustment wheel to rotate. You may need a pair of pliers to slide toggle upwards.
*Do not use too much thread tape, or over-tighten. Breakage of the glass-reinforced threaded nipple is not covered by warranty.
Hurlcon & Astralpool: Part # 71580 (OEM) 800122-3
- HX 70, HX 120, HX 150, MX 150, MX 200, MX 250, MX 300, MX 350, MX 400, MX 500, JX 130, JX 160, HiNRG 175, HiNRG 250, HiNRG 400, Viron 250, Viron 350, Viron 450, Viron 550, WX 70, WX 120, WX 150, ICI 200, ICI 400,
- Also used in Astral BPM and BPA heat pumps - BPA 400, BPA 600, BPA 700, BPA 800, BPA 900, BPM 400, BPM 600, BPM 700, BPM 800, BPT 900 and other BP series heaters.
Specifications:
- Voltage: 12V to 24V
- Part Number: 800120 - Supersedes 800140 / 800130 / 800122 / 800***
- Contact Rating: 21A - Normally-Open or Normally-Closed
- Adjustment: 1-5 psi / 6.9-34.5 kPa / 0.7-3.5 meters head
- Thread: 1/8" NPT (approx 6mm) - Originally Stainless Steel. Now Noryl for corrosion-resistance
Len Gordon LG Part Nos:
- ALLIED Innovations 800*** 800120-3 | 800140 | 800130 | 800132-3 | 800134-3 | 800122 | 800123 | 800140-0 | 800140-3 | 800140-4 | 11/13 6AMP more.
Manufacturer Catalogues, Diagrams & Part Numbers
Need exploded views, spare part numbers, product numbers, diagrams, or more product information? See the manufacturer catalogues: Astralpool Catalogue 2026 | Zodiac Catalogue 2026
Interactive Parts Diagrams
Find this part on our interactive heater parts diagrams — each one opens the full exploded view and parts list:
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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