FAQ
TL;DR: A ±10 g R410A error equals only 1 % on an 800 g split, and "the reading from the manometer gives a larger error" [Elektroda, Chris_W, post #17269292] Add 10 g per metre over 5 m; small deviations rarely harm output.
Why it matters: Understanding real tolerances saves money, protects hardware and keeps you inside F-Gas law.
Quick Facts
• Factory R410A charge covers the first 5 m of piping; add 10 g per extra metre [Elektroda, Jan_Werbinski, post #17267586]
• Typical split holds 800 g; ±30 g (≈4 %) stays within manufacturer spec [Elektroda, Chris_W, #17269292; Daikin Tech Guide].
• Correct pressure test: 40 bar nitrogen for R410A systems [Elektroda, Jan_Werbinski, post #17269274]
• Any installation or service requires personal and company F-Gas certificates, regardless of charge mass [Elektroda, Chris_W, post #17277850]
• Basic legal tool kit (vacuum pump, gauges, nitrogen set, scale) costs ≈ PLN 8 000 [Elektroda, Jan_Werbinski, post #17277880]
How much R410A should I add when my pipe run exceeds 5 m?
Add 10 g for each metre beyond the initial 5 m. A 6 m run needs 10 g; 7 m needs 20 g [Elektroda, Jan_Werbinski, post #17267586]
My scale’s resolution is 20 g—how do installers handle such tiny doses?
Technicians usually over-fill slightly, listen for flow noise, then fine-tune by suction pressure and temperatures rather than the scale alone [Elektroda, pawel1148, post #17267646]
Will a 10–20 g undercharge hurt cooling performance?
No measurable drop appears at 1–2 % charge error; tables show larger uncertainty [Elektroda, Chris_W, post #17269292]
Is it safer to leave the factory charge untouched for a 6 m line?
Yes. Running on the original charge keeps you within ±1 % and avoids venting losses [Elektroda, Chris_W, post #17269292]
Are single-stage vacuum pumps acceptable for new installs?
Yes. They reach required 500 microns; they just need longer run time than two-stage pumps [Elektroda, Chris_W, post #17269292]
Do I really need a 40 bar nitrogen pressure test every time?
Standards require it, but many crews skip it if they trust their flares and vacuum hold [Elektroda, Jan_Werbinski, post #17269274]
Can I pressure-test with compressed air from a diving tank?
Avoid it. Air contains 20 % oxygen; at high pressure oxygen can react with POE oil, raising fire risk [Elektroda, Chris_W, post #17273389]
What happens if the system loses 20 % of its refrigerant?
You can see local exchanger icing, 10–30 % efficiency loss and possible compressor damage [Elektroda, pawel1148, post #17267646]
Does Polish law require an F-Gas certificate for small splits under 3 kg?
Yes. Article 20 demands certified personnel for any installation or service involving F-gases, independent of charge size [Elektroda, Chris_W, post #17277850]
Can a hobbyist legally install a single household air-conditioner?
Only if certified or working under direct, documented supervision of a certificate holder, per EC 308/2008 Art 4 3 a [Elektroda, Jan_Werbinski, post #17277857]
My unit sat open to air for a year; how do I revive it?
Replace compressor oil, change the drier, nitrogen flush, vacuum 24 h, then recharge [Elektroda, p.obelix, post #17995294]
3-step How-To: Replace compressor oil and dry the system
- Desolder compressor, drain oil fully by inverting and rocking until no sound.
- Re-braze under low-flow nitrogen, install new drier, pressure-test, then vacuum 24 h.
- Add fresh POE oil, hold 500 microns, charge by weight, run test [Elektroda, 18000483-18000558].
What tools and budget meet legal compliance for start-ups?
Expect PLN 8 000 for pump, manifold, calibrated scale, nitrogen regulator, leak detector and paperwork fees [Elektroda, Jan_Werbinski, post #17277880]
Why can oxygen under pressure ignite refrigeration oil?
Fire risk rises hundreds-fold as oxygen partial pressure climbs; pure or enriched oxygen can auto-ignite hydrocarbons [Elektroda, Chris_W, post #17273389]
