Bonfix
Bonfix stainless steel press bends for pool pipework
Bonfix supplies metal pipework fittings, and the items listed here are all from one family: 90° bends in stainless steel 316L with press ends, carrying a KIWA marking. They are used where a pool installation moves away from plastic pipe and into metal — plant room headers, heat pump and boiler connections, buffer tank runs, manifolds and any section where rigid, fire-resistant pipework is preferred to glued PVC. A press bend simply turns the pipe through a right angle without threading, soldering or a flame on site.
Diameters in this range
Here you will find the 90° press bend in six tube diameters, covering most of the sizes used in domestic and light commercial plant rooms:
- 15 mm – small branch lines, dosing and instrument runs.
- 22 mm – typical for short connections and secondary circuits.
- 28 mm – common on heat pump and heat exchanger primaries.
- 35 mm – larger circulation runs and plant headers.
- 42 mm – main flow and return on bigger pools.
- 54 mm – the largest size in the range, for main distribution pipework.
The sizes refer to the outside diameter of the tube the fitting presses onto, which is how metric press systems are always designated. Measure the pipe itself with a caliper over the bare metal, not over insulation or paint, and order to that figure. A 28 mm bend will not press onto 35 mm tube, and the two are easy to confuse by eye.
How press ends work and what to check first
Each socket of the bend holds a seal in a bead at the mouth. The tube is pushed home, and a press tool with the correct jaw profile deforms the socket around the tube and the seal in a single stroke, producing a joint that cannot be undone. Because the connection is permanent, a few checks are worth making before you press:
- Jaw profile – press systems use different profiles, so confirm that your tool and jaws match the fitting profile and size before committing to a joint.
- Insertion depth – mark the tube so you can see it is fully seated; a short insertion is the most common cause of a leaking press joint.
- Tube preparation – cut square, remove the internal and external burr, and keep swarf out of the socket so the seal is not cut.
- Seal present and undamaged – check the O-ring is still in its groove after handling and that it has not been twisted or displaced.
- Seal compatibility – the standard seal in a press fitting is chosen for the medium it carries, so check the intended fluid and temperature against the manufacturer’s data rather than assuming one seal suits everything.
Why 316L, and where to be careful
316L is a low-carbon austenitic stainless steel containing molybdenum, which is why it is specified more often than 304 in damp and chemically loaded environments. The low carbon content reduces carbide precipitation at the grain boundaries, which matters on welded and worked components.
That said, no stainless steel is indifferent to chlorides, and pool halls and treated pool water can be demanding. Keep metal pipework out of the chemically dosed section of the circuit unless the designer has specified it, rinse and dry surfaces exposed to splash, avoid trapping damp insulation against the metal, and use the correct isolation where stainless meets dissimilar metals such as copper or galvanised steel. Store and cut stainless with clean tools so that carbon steel particles are not embedded in the surface.
Bonfix at PoolParthub.com
Here we list the Bonfix 90° stainless steel 316L press bend in 15, 22, 28, 35, 42 and 54 mm, including the catalogue references 0085087, 0085089, 0085090 and 0085093, so a fitter can order the exact diameter needed rather than a mixed assortment.
They are stocked because plant room pipework is where pool installations most often step up from plastic to metal, and a single missing elbow in the right size holds up the whole run. Having the full diameter ladder available in one place makes it straightforward to complete a header, add a branch or replace a damaged bend without changing system.