Name:   Lifer - Subject:   Plumbing/Water Heater Question Date:   4/22/2014 1:52:19 PM

I have done a good bit of plumbing in the past including installing new and replacing old water heaters but I have a problem that has me a bit puzzled.  The heater in question is between 14 and 20 years old.  I assume it was installed when the house was built in '93 but a major remodel to the house happened prior to my purchase in 2000 so it coould have been upgraded.  The pop off valve went bad 4-5 years ago and I replaced it with no issues till now.  A mildew smell began in the master bedroom closet last week.  Mild at first but grew stronger after a couple of days.  tracked it down to wet carpet so of course I checked for leaks in master bath and the utility closet on the other side of the back wall of the closet.  The pop off valve line runs through that wall to the outside.  I fould find no trace of a leak in it and of course knew that there shouldn't be any water flow through it anyway.  We left the carpet pulled up and put a small heater in to dry the carpet out.  Over the next few days there was no sign of additional leaks.  Then Sunday I checked the drain line again for the 3rd or 4th time and found water dripping at the low point.  Dried it all up and left a dry towel underneath and when I checked it after a while it was wet but not soaked.  Left it in place and checked a few hours later and it was soaked.  I replaced the towel with a bowl and collected very little water Sunday night and Monday.  Looked this morning and there was several ounces of water. I emptied that and was planning a trip to Moore's for a replacement valve but when I looked again to determine what fittings I need it was bone dry.  Through all this I never heard the pop off valve "blow" at all and I never heard of one leaking a little bit.  MY experience is they blow out due to pressure or go bad and leak profusely.  Obviuosly I have a bad joint in the PVC but my concern is the pressence af any water in the line.

So here is my question.  Considering that I have already replaced the valve once should I just do it again or is there a potential problem with the tank that would warrant relacing the whole unit?  It works fine in so much that it heats.  I am really puzzled as to why there is water in the blow off line at all.  Am I missing something?  Any any advice or counsel will be greatly appreciated.