Blast: Pressure Washer Calc — Support

Need help?

Email roman.kopaliani@gmail.com with your question. Please include:

• What you were trying to do
• What happened instead
• The app version (Blast → More → About)

Frequently asked

What's free and what's in Blast Pro?

Free forever: the Consumer Reports surface guide (PSI bands plus the never-wash list), the nozzle color reference, and Wash Safe. Blast Pro ($6.99, one-time) unlocks the nozzle-size calculator (CAT Pumps formula) and soap & dilution. No subscription.

What PSI does my surface take?

Per Consumer Reports: wood and composite decks 800–1,000 PSI with a wide nozzle; vinyl and fiber-cement siding 1,200–1,500; concrete driveways 1,500–3,000. Start wide, far, and low — test an inconspicuous spot first.

Why does Blast say never pressure-wash my car?

Because Consumer Reports says so: the jet can nick paint, and nicks invite rust. Plenty of blogs publish a "safe car PSI" — Blast ships CR's verdict instead: hand-wash or use low-pressure foam. Same for roofs: blowback can throw you off a ladder, and the jet strips shingle granules.

Which nozzle number do I buy?

Per CAT Pumps' standard selection chart: a nozzle number is its flow in GPM at 4,000 PSI, and your size is GPM × √(4000 ÷ PSI) from your washer's rating plate, rounded to the nearest half-size. The Pro calculator does this and shows your cleaning units (PSI × GPM).

What about the colored tips?

Industry standard: red 0° (avoid it — per CR the pinpoint jet can pierce boots and skin), yellow 15° for stripping, green 25° for general work, white 40° for delicate surfaces, black for low-pressure soap.

Does it work offline?

Yes — Blast never makes general network requests. The exception is Apple's StoreKit (price fetch, restore). Everything else is local.

Is Blast a guarantee?

No. Blast is an educational reference that shows published guidance alongside your inputs. Surfaces, washers, and detergents vary — test first, follow your washer's manual and the detergent label, and treat the jet as the blade it is.

Refunds

Purchases are handled by Apple. Request a refund at reportaproblem.apple.com.