There are no specific torque settings for the diaphragm clamp or for the environmental end cap. The diaphragm clamp requires "metal to metal" contact and it is typical to use the spanner tool. The environmental cap is "hand tight". My experience is that getting "metal to metal" contact requires more effort than "hand tight". So I have not seen an issue where tightening the end cap will move the diaphragm clamp and change the IP when following the "metal to metal" and "hand tight" directions.
If an 11/16” open end wrench and a torque wrench with an 11/16" crows foot is used, it is simple to apply 45 inch-pounds of torque to the LP hose without causing any changes to the heat exchanger torque or causing the spindle to move within the body. I agree a better design would limit that issue, but we have what Apeks delivers.
To answer the question of "Why would you ever torque the hose tighter than the heat exchanger?" I do it EVERY time I service a customer's regulator. When working on customer's regulators I follow the manufacturer's stated specifications in their service documents. If ever called to court in the event of an accident, I am not going to use the the defense of "Apeks did not know what they were thinking, so I did it my way." When you service your own equipment, you have the liberty of defining your own specifications as you see fit.
I suspect the vast majority of Apeks regulator owners are not tightening the LP hoses and using only a single wrench. They either don't install or change their own hoses or they are aware of the problems of moving the spindle and use two wrenches to keep the heat exchanger in place. Sending customer's regulators out with "finger tight" LP hoses on their second stages is a liability. If they want them finger tight they can loosen the LP hose after it has been delivered meeting manufacturer specifications...hopefully by using two wrenches to avoid loosening the heat exchanger!
OP asked about cracking on XTX 2nd stages. This is a known issue with Apeks second stage bodies and Apeks issued a change to the torque specification of the heat exchanger in 2011. That updated specification has remained for 10 years and it is still 27 inch-pounds (3Nm).
If an 11/16” open end wrench and a torque wrench with an 11/16" crows foot is used, it is simple to apply 45 inch-pounds of torque to the LP hose without causing any changes to the heat exchanger torque or causing the spindle to move within the body. I agree a better design would limit that issue, but we have what Apeks delivers.
To answer the question of "Why would you ever torque the hose tighter than the heat exchanger?" I do it EVERY time I service a customer's regulator. When working on customer's regulators I follow the manufacturer's stated specifications in their service documents. If ever called to court in the event of an accident, I am not going to use the the defense of "Apeks did not know what they were thinking, so I did it my way." When you service your own equipment, you have the liberty of defining your own specifications as you see fit.
I suspect the vast majority of Apeks regulator owners are not tightening the LP hoses and using only a single wrench. They either don't install or change their own hoses or they are aware of the problems of moving the spindle and use two wrenches to keep the heat exchanger in place. Sending customer's regulators out with "finger tight" LP hoses on their second stages is a liability. If they want them finger tight they can loosen the LP hose after it has been delivered meeting manufacturer specifications...hopefully by using two wrenches to avoid loosening the heat exchanger!
OP asked about cracking on XTX 2nd stages. This is a known issue with Apeks second stage bodies and Apeks issued a change to the torque specification of the heat exchanger in 2011. That updated specification has remained for 10 years and it is still 27 inch-pounds (3Nm).
