Problems with the nozzle-end seal on the PentaMax 54mm motors, specifically when used in the 5-port configuration have come to light both during recent test-stand testing, and during field use by end-users.
The cause is the "mushiness" of the nozzle insulator washer (packed with reload kits) along with a marginal seal caused by random variations in chamfer angle in some reloads.
The fix is to *eliminate* the use of the nozzle insulator washer--even without this washer, thermal-loading is well within limits. The motor has been used on the stand in this configuration many, many times. Reload kits will have the DASH#221 'O' rings replaced with DASH#324 'O' rings.
In the near future, motors will be supplied with a stainless steel backup washer to be used between the nozzle snap ring and the nozzle. The purpose being to prolong the life of the nozzle by reducing wear between the snap-ring and nozzle.
If you are in posession of a PentaMax reload kit, please contact your dealer, or snipped-for-privacy@propulsionpolymers.com to get replacement 'O' rings.
There are currently only a handful of fielded units, and we apologize to those users for any inconvenience.