CO₂ gas train

Safety

Keep the solenoid manual override closed (horizontal line pointing at 0 on the front of the solenoid) except when venting. The solenoid valve must be 3-way venting (3/2). A 2-way valve traps CO₂ between the valve and the broth on closing; the CO₂ dissolves and draws liquid back up the line.

This step builds the valve train with no cylinder fitted. Admit CO₂, next, fits the cylinder and opens it once the Loctite 577An anaerobic thread sealant: it cures only without air, inside a tightened thread. Fixtures in 10 to 60 minutes at 22 °C; full pressure after 24 hours. has fixtured.

1. Apply Loctite 577 to the second thread (not the end one) of the joint between the regulatorDrops the cylinder's pressure (about 60 bar when full) to a working pressure, about 1 bar here. Its flathead screw fully anti-clockwise is closed. outlet and the solenoid valveAn electric valve on PWM channel 4 that opens to sparge. It must be 3-way venting (3/2), so the line vents when it closes.’s left port, and screw the solenoid valve on, electronics to the rear. Work up to vertical; do not pass it and turn back.
2. Holding the solenoid, apply Loctite 577 to the blanking plugA 1/8" threaded plug that seals the solenoid's unused right port. It seals on its own o-ring, so it needs no sealant.’s second thread and screw it into the solenoid’s right port with the 5 mm hex key.
3. Apply Loctite 577 to the needle valveA fine-adjustment valve on the solenoid's front port. It sets how fast CO₂ flows; turn clockwise to close.’s inlet thread (second thread), and screw it into the solenoid’s front port, stopping with it pointing straight up.
4. Close the needle valve (clockwise), and check the solenoid manual overrideThe dial on the front of the solenoid. 0 is normal (closed without power); 1 holds the valve open. is at 0.
5. Wait for the Loctite 577 to fixture before admitting gas: 10 to 60 minutes at 22 °C. It reaches full pressure rating after 24 hours.

Notes

• Solenoid override: 0 is normal (closed without power); 1 is always open.
• Loctite 577 is anaerobic thread sealant, not glue. Skipping the end thread keeps it out of the gas path. Clean the threads with ethanol first where you can.
• Do not use PTFE tape in the gas train. Applied correctly it seals, but it is fiddly and leaks too often.

Parts

• 1×FZone CO₂ regulatorpart
• 1×Solenoid valvepart
• 1×Loctite 577 thread sealantconsumable
• 1×CO₂ needle valvepart
• 1×1/8" blanking plugpart

Tools

• 1×5 mm hex keytool

Check your work

1. How long ago did you screw in the needle valveA fine-adjustment valve on the solenoid's front port. It sets how fast CO₂ flows; turn clockwise to close., the last Loctite 577An anaerobic thread sealant: it cures only without air, inside a tightened thread. Fixtures in 10 to 60 minutes at 22 °C; full pressure after 24 hours. joint?

   • Between 10 and 60 minutes ago
   • Less than 10 minutes ago
   • An hour or more ago
   Show the answer

   Answer: An hour or more ago

   • If you see Between 10 and 60 minutes ago: It may not have fixtured yet: at 22 °C that takes 10 to 60 minutes. Wait until the hour is up before admitting gas. Full pressure rating takes 24 hours.
   • If you see Less than 10 minutes ago: Wait: Loctite 577 fixtures in 10 to 60 minutes at 22 °C. Admit gas only after that. Full pressure rating takes 24 hours.

2. What does the solenoidAn electric valve on PWM channel 4 that opens to sparge. It must be 3-way venting (3/2), so the line vents when it closes.'s manual overrideThe dial on the front of the solenoid. 0 is normal (closed without power); 1 holds the valve open. point at?

   • 0 (horizontal line at 0)
   • 1 (horizontal line at 1)
   Show the answer

   Answer: 0 (horizontal line at 0)

   • If you see 1 (horizontal line at 1): Turn it to 0. At 1 the solenoid is always open, so gas would flow as soon as the cylinder opens.

≈ 0.02 g CO₂e per view