MollFAM

MollFAM tubing clamps for pool and spa lines

Small fittings keep a pool installation tight, and clamps are among the smallest of them all. The MollFAM range listed here covers clamps for flexible tubing in three common sizes — 1/4 inch, 3/8 inch and 3/4 inch — the diameters used for ozonator air lines, chemical dosing tubes, air injection lines and short lengths of flexible hose around pumps, blowers and control equipment. A clamp costs a fraction of the parts it secures, yet a loose one can let air into a suction line, drip dosing solution onto equipment, or allow a tube to walk off its barb while the system is running.

Here you will find the clamps on their own, which is how most people need them: the tubing is often still perfectly serviceable, but the original clamp has been cut off during a service, has corroded, or has been over-tightened once too often and no longer holds its shape.

Which size do you need?

Tubing is normally described by its inside diameter, while a clamp has to close around the outside diameter of the tube once it is pushed onto a barbed fitting. The simplest approach is to match the clamp to the stated tubing size and not to the measurement you take with a tape over a tube that has already swollen on a fitting.

• 1/4 inch — the thin line typically running from an ozone generator to the injector or check valve, and used for small chemical feed lines.
• 3/8 inch — a step up in air and dosing lines, also found on some air controls and small bleed lines.
• 3/4 inch — heavier flexible tubing, short jumpers and air lines around blowers and manifolds.

If the existing clamp is still in place, read the size off the tubing itself where it is printed, or measure the tube end with a vernier once it is off the barb. When a tube sits between two nominal sizes, it is worth checking whether the previous installer substituted a different diameter at some point — mixed sizes are common on systems that have been serviced several times.

Where these clamps are used

Ozone systems are the classic application. An ozonator pushes a small volume of gas down a narrow tube to an injector on the return line, and that tube is under constant movement from vibration and temperature change. A clamp at each end stops the tube creeping off its barb, which would otherwise send ozone into the plant room instead of the water. The same thinking applies to:

• Chemical dosing lines — peristaltic pump outlets, suction lances and injection points, where a slipped tube means spilled product.
• Linii de aer — spa air controls, blower runs and air bleeds, which need to stay sealed to keep the intended air-to-water balance.
• Short flexible jumpers — pressure gauge tappings, drain lines and bypass tubes on filtration and heating equipment.
• Vacuum and suction side connections — anywhere a pinhole leak would let air into the circuit and cause a pump to lose prime.

Fitting and replacing clamps

Work with the system switched off and the line depressurised. Slide the new clamp onto the tube before pushing the tube over the barb, not after — forcing a clamp over a tube that is already seated is how tubing gets nicked. Push the tube fully onto the fitting so that it covers the whole barbed section, then position the clamp behind the last barb rather than on top of it, so it squeezes the tube into the groove.

Tighten until the tube is held and the line no longer twists under hand pressure, and stop there. Over-tightening thin-wall tubing cuts into the wall and creates the leak you were trying to prevent. After refilling and restarting, check the joint again once it has warmed up, because flexible tubing relaxes slightly in use and a clamp that felt firm cold can need a final nip. If a tube has gone hard, discoloured or has split ends from repeated refitting, replace the tubing as well — a new clamp cannot seal a tired tube.

MollFAM at PoolParthub.com

Here we list the MollFAM clamps for 1/4 inch, 3/8 inch and 3/4 inch tubing, each available separately so you can order only what your job needs. Part numbers PPS-10036, PPS-10037 and PPS-10035 correspond to the three sizes, which makes reordering straightforward once you know what fits your installation.

These are the kind of parts people need in small quantities and at short notice, usually in the middle of a service. Keeping the three common sizes together on one page means you can check your tubing diameter, pick the matching clamp and add it to an order alongside the tubing, injectors or dosing parts it belongs with.