Nuova Simonelli Oscar Anti-Vacuum Kit

Oscar Boiler Anti-Vacuum Conversion Kit

A complete parts kit that converts the boiler fitting on the Nuova Simonelli Oscar to accept an anti-siphon (anti-vacuum) valve, letting air escape as the boiler heats instead of drawing air back through the group on cool-down.

SPECIFICATIONS

• 1 x boiler safety valve
• 1 x anti-vacuum valve
• 4 x PTFE gaskets (2 for the safety valve, 2 for the tee's female port)
• 1 x copper gasket for the anti-vacuum valve
• 1 x 1/4" BSP female x male x female tee fitting

COMPATIBILITY

• Fits: Nuova Simonelli Oscar
• Works with: existing pressurestat and boiler safety valve assembly

INSTALLATION

This is a boiler plumbing job with the machine fully depressurized and unplugged — comfortable for an experienced DIYer, but we recommend a technician if you haven't worked inside a boiler before.

Assemble the kit first, tightening every fitting as tight as possible; PTFE tape can be used on the threads, though the included gaskets are meant to make that unnecessary. With the machine off, unplugged, and the boiler fully depressurized, label the wires to the pressurestat, then remove the pressurestat, safety valve, and the tee fitting below it. Thread the assembled kit into the side of the tee so the assembly sits horizontal to the boiler — exact orientation isn't critical as long as every fitting is tight enough to seal. Run the original fixing nut all the way onto the old tee, thread the whole new assembly back onto the boiler as tight as possible while keeping it close to its original position, then lock it down with the fixing nut. Reinstall the pressurestat and reconnect the labeled wires.

PRO TIPS

• Some steam hissing from the new fittings on the first heat-up is normal — it stops once the fittings expand with heat and seat fully. Don't over-tighten trying to chase it away on a cold machine.
• After firing the machine back up, let it run 30 minutes and physically inspect every fitting for weeping or drips before calling the job done.