H2O Pump Loop 1 Warning

[thammond]

Running the STS-1 again.  I have the crew activity plan for STS-1 so I figured I would try out some of the crew activities while on orbit.  So the 1st item on the STS-1 crew activity plan is to turn ON "H2O PUMP LOOP 1 B"

So I went ahead and tried that.  The result was warning sirens and lights.  In particular the siren sounded, the Master alarm light illuminated red, and on the C/W display (F7) the H2O LOOP illuminated yellow, BACKUP C/W ALARM and PRIMARY C/W illuminated red.

So I figured this would be a good learning exercise and pulled out the SCOM to figure out what happened and why.

From the SCOM, my understanding is that there are two redundant cooling water loops.  Loop 2 is the normal loop used on orbit and that running both loops is not recommended as it would over tax the H2O/Freon heat exchanger.  But nowhere did I see it suggest that both loops couldn't be used at the same time.

Furthermore it states that the H2O LOOP C/W will illuminate if the pressure of loop pump 1 is less than 19.5 psi or greater than 79.5 psi.

So I brought up the SPEC 88 DISP to see what the pump pressures were at.  The SPEC 88 DISP values are 0 for pump 1 and 56 for pump 2.  So OK that would explain why the alarm went off.  But not sure why the pressure would go to zero when the pump1 is turned from OFF to ON?

So I tried turning the LOOP 1 PUMP back OFF.  The results for turning the pump 1 off was that the C/W lights went off.  However when I went back to the SPEC 88 DISP, the LOOP 1 pressure was still reading zero (which should result in a C/W warning?).

So the question for anyone out there is am I missing something in my understanding of the ELCSS systems or is this not modeled correctly in SSM (I realize this is outside the intended scope of the ssm program and is not intended as any kind of criticism of the program, just clarification).  Because it seems to me that turning on the pump for loop 1 should not result in a warning.

[Admin]

Been a while since anyone used SSM2007 instead of the new version, so it took a while before we realised that the GPS MAJ FUNC needed to be set to SM before you even could activate the SPEC 88 DISP.

Most of the background systems are simulated to a certain degree, but this one
 seems to be a plain programming error

We hope to be able to add more functionality of any possible errors in the next version, but it will probably be in a future add-on for the new version.
But we can always start fixing this one.

Admin