The measured dew point today was -8C.  We have not been measuring this frequently enough and can't definitively determine if this is a new problem, or, if it has been ongoing for some time (weeks?).  Rather, we have just checked to see if the drying towers have been experiencing "Switching Failures" which are the most typical problem associated with poor dew point numbers. 

The pressure of the air which backflows through the towers during their "regeneration" cycle (coincidentally referred to as "purge-air") was about 40 psi -> 65 psi is nominal for the 4 minute cycle time being used.  I was only able to increase/adjust this to ~50 psi .  So, something is amis.  This issue is likely the majority of the problem but, additionally, there is a second problem.  That is that the gauge at the output of the vent/purge air supply skid is showing 0.1 psi -> as if the demand from the VEA was greater than could be supplied by the skid.  This is surprising as the observed demand at the vent/purge check valve is modest when the 2 1/2" vent/purge valve is closed.  One explanation could be that there is a leak in the parallel connected TMDS piping.

We will address this as soon as we can.