I've heard of, but not tried, adding some food coloring to the water in the tank to do the same thing.Sometimes on a new-build house, or one where they've done lots of plumbing work, a plumber will pressurize the lines with air, from a compressor, to check for leaks. 

The plantiff was a Hard Money lender and the defendant an LLC.There were no photos of the inside of the home on the internet, but I did a walk-by before the auction and could notice plenty of enhancements- new paint exterior, new windows, new AC compressors out in the back lawn, some electrical conduit ran, nice light fixtures and swimming pull furniture, etc. 

They weren't happy about it, but too bad.Oh, and in June we had to replace the compressor for the air conditioner at house #7.

And if u get the bad compressor in hvac or something big just going to shell out cause warrenty companies will try to void anything big by any means and the tech will bs and get it voided if its big ticket stuff because of commission based worked.

I guess I will also need the compressor in the outside unit, which is currently missing.

The company that did the repair did not braze the line properly and all the refrigerant leaked out and with the tenant being gone for a 4 day weekend the compressor locked up and just like that a new evaporator and condenser on a 6 year old unit. 

This is what one company's tune up entails:Spring AC tune up:Indoor Unit*Blower Motor *Amp Draw *Bearings *Blower Wheel Balanced *Control Board *Operating Properly *Incoming Voltage*Connections *Low Voltage *Electrical Connections *Change/Clean Filter *Capacitor *Thermostat *Check Operations *Outdoor Unit*Compressor*Amp Draw*Condenser Fan Motor*Amp Draw*Bearings*Capacitor*Electrical Connections*Clean Condenser Coil(water)*Check Refrigerant Levels*Check Contactor *Relays Operation*Check Operations*Clear Condensation Lines*Furnace:Fall Maintenance Checklist*Replace Filter*Electrical Connections*Check Thermostat*Verify Blower Condition*Check Control Operations*Check Control Board*Check Capacitor(s)*Amps of motor operations* Check Relays*Heat Exchanger Condition*Burner Condition* Remove and clean flame sensor* Inspect Blower Wheel*Inspect and check ignition operations* Check ALL safety operations* Verify a good clean burning flame*Are these pretty standard work supposed to happen for tune ups? 

Tomorrow, will be another $3000 if bring out the air compressor or need to build a new pipe.

Take an air compressor and generator,  put the generator outdoors, hook up the compressor to the boiler, turn compressor on and listen for air rushing out of any breaks. 

I've heard of inspectors frying AC compressors and furnaces after shorting circuits, so this is nothing.