Raypak 406A Header question

wireform · Apr 5, 2024

I removed the inlet/outlet polymer header on a Raypak 406A heater to inspect the heat exchanger.... I ordered a new gasket but the instructions aren't clear to me when it describes the tightening pattern. I think I know how I want/need to bolt it back. My thinking is do the center top and bottom, then do a row top and bottom next to it, then do a top and bottom of the row to the other side of the center first row...and keep working from the center towards the two ends so this way it can spread itself out evenly. The document that came along with the new gasket is not clear enough what they want you to do.

ajw22 · Apr 28, 2024

What pattern did you follow to tighten the bolts?

wireform · Apr 28, 2024

Did the first round snugish and then again tight by feel. No leaks going on three weeks. Make sure grove is lubed before the gasket is inserted and then the gasket after it's in groove before mounting.

JamesW · Apr 28, 2024

I do not think that the pattern matters.

The key is to do many laps around and only tightening a little bit on each lap.

Maybe 3 to 5 laps is enough and only getting snug on each lap with the last lap being the correct torque.

wireform · Apr 28, 2024

Correct, but the idea is also to start in the middle and work towards the sides to spread it so it can go down without a high spot.

JamesW · Apr 28, 2024

As long as you only tighten each a little bit at a time, it should not matter.

Ideally, you should tighten all simultaneously at the exact same torque.

JamesW · Apr 28, 2024

Build a device with 12 electric torque sockets that are all synchronized to have the exact same torque and increase the torque from zero to the specified torque according to the manufacturer's torque acceleration protocol.