Engine cold loop overheating and overpressurising tremendously

[zekesulastin]

Brief description of the issue

Once gas is added to the cold loop of the engine, the pressure and temperature will immediately jump (in the test case, to about 3300 kPa and 3900 c

What you expected to happen

The pressure and temperature to increase very slightly as gas is added

What actually happened

The pressure differential became so great that the cold loop began sinking to the hot loop. In a previous long running round the pressure and temperature exceeded 110000 kPa and 150000 c

Steps to reproduce

1. Start the server
2. Load a canister of phoron into the cold loop

Additional info:

• Server Revision: 57232772193201f3be6f027f3a4008dd7189c621
• Anything else you may wish to add Reverting 76b195f1a9321920cc1d3253b667f94bca3b4084 (#8409) restores expected operation of the loop.

[zekesulastin]

It does look like more than just the cold loop - the waste heat loop that's not physically connected to the engine loops is also hitting "The pressure gauge reads 73982.6 kPa; 44754.6K (44481.5°C)" over time.

I built a random heat loop indoors that wasn't affected, though. Couldn't check the toxins one in round because toxins got toxins'd.