PRESSURE IN.
ANSWERS OUT.
Air con and heat pump diagnostics. Put in the readings you've already got and find out whether it's a real fault or a system doing its job.
No account, no sign-up. A real Mitsubishi flashing 17, from callout to verdict. Or put your own readings in.
Live · R32 · sample wall split · 30°C day
Real physicsLeak, or a long pipe run never trim-charged at install.
Every fault code cites the manual and section it came from.
The real thing
That chart lives in your pocket
Gauges on, or the figures off the unit's own service menu when there are no ports on the job. The app plots your actual cycle and calls it: within tolerance, or ranked likely causes with the reason for each one.
“Brilliant app, helped me loads so far and I’m only 2 days in 👍”
A working F-Gas engineer, using it on live commissioning jobs.
What's inside
Built for the job, not the brochure
Fault codes that go somewhere
950+ codes across 18 makes, each opening a step-by-step flow: what to test, how to test it, and what a good one should read. Where a code is the machine protecting itself rather than a fault, it says so instead of sending you hunting. No dead ends that just say replace the board.
Before you break into the circuit
Controller access for the service menus, and the app knows what each sensor means on that model. Condensing temperature and subcooling read off the unit's own sensors, labelled honestly when the figure isn't from your gauge — so you only break into the circuit when that's the right call, not by reflex.
Know the additional charge is right
How much extra gas that pipe run needs, from the unit's own published grams per metre and the pre-charge already in it. Adding gas on a new install, it gives you the figure. Already got one written on the F-Gas label, check theirs against it and see if it was sized right.
The paperwork
Done in the van, not at the kitchen table
Job packs, service reports, commissioning certificates, quotes, invoices, tightness test records, waste transfer notes and the F-Gas register. Fill it in once on your phone and every document goes out on your branding, with your sign-off.
5 May 2026
Daikin Altherma 3 · 11 kW · R32
For every kilowatt of electricity paid for, this system delivered ≈ 3.6 kilowatts of heat — the other ≈ 2.6 came free from the outside air.
F-Gas Cert. C-1180244
5 May 2026 · Due in 14 days
Job 24-05-2107 · Daikin Altherma 3 · 11 kW · R32
VAT No. GB 123 4567 89
Readings from the diagnosis drop straight onto the report. Charge and GWP become tCO₂e on their own, and the app knows when a leak check is a legal requirement.
Free for everyone
10 tools, no account, no catch
Where the numbers come from
Fault flows, sensor curves and charge figures are pulled from manufacturer service manuals and databooks, model by model. When a figure isn't published, the app says so rather than inventing one.
Pricing
Free to start. Launch rate, locked while you stay.
Free
£0Pressure test checker, thermistor and refrigerant converters, AC sizing, all the guides, and the diagnosis demo. No card, no trial clock.
Pro · Launch rate
£9.99/moOr £99 a year. Locked for as long as you stay subscribed — the price rises for new sign-ups later, not for you.
See what's in Pro"I'm an engineer, not a software company. Someone who doesn't do F-Gas should be able to read a screen and go 'right, that makes sense'. If it can't be said that plainly, it isn't finished."
Why we do this