Move bed to assisted living facility with limited elevator and stairwell access

Hello,

I have a Totalcare P1900 that as of today the foot of the bed will not lower using the hi lo button at the top side rail.   The head will lower, but the foot is now at maximum height.   Hitting the lower button keys the head lower but the foot stays in place,  just like putting the bed in Trendelenberg position.   I called support and they had me swap the solenoid for the up and down high low,  but this had no effect.   He said it it's probably the valve that is stuck and can be removed from the manifold to be cleaned or replaced.   How do i remove this valve from the manifold?  Is there a way to manually lower the bed?  I took bolts off the bracket on the foot of the large hydraulic cylinder for the bottom section,  but didn't see how to release it.  Any suggestions or copies of the service manual for this bed would be appreciated.  We moved my son to a small makeshift bed until we can get this lowered to normal level height out fixed.   Thank you! 

Equipment: Totalcare P1900

Equipment: Hillrom - Totalcare P1900 sport