I came across an intake / exhaust set up today that I have not come across before. The exhaust and intake come out the top of the furnace (photo #1) take a 90 degree turn and join in at a Y fitting (Photo #2) and terminmate at the exterior with the smaller intake extending about 12 inches past the larger exhaust. (It also appeared to be sucking rain water in and I did recommend having a licensed HVAC contractor further evaluate and repair as necessary just fyi) Thoughts?
It looks to be a homemade concentric vent. These usually come as a kit and are pre-made and listed for this application (One hole in the wall to vent exhaust and provide intake). I agree, further evaluation by a qualified HVAC mechanic. Good catch.
Concentric vent, looks properly installed. You state leaking ?? You sure its not the condensate. High-efficiency furnaces are designed to have the condensate flow back into the furnace, where it is then drained by gravity out of the heat exchanger and into the condensate pump . Wherr did u see the ‘leaking water’
Should have a proper termination imho.
In the 2nd pic it looks like it’s “sealed” with silicone and the silicone is detached.
Are the pipes glued together or loose?
Here are a few different examples of HE venting options, each mfg has different types - some have elbow fittings outside , ‘T’ fittings, straight pipe, etc.
But as Tom said, most concentric types have a rain hood on the end, maybe not installed since it is side wall and no rain can enter ??, check with mfg of the heating unit.
Whats wrong with tons of silicone ? :o)- , couldnt see that on my Iphone but saw it on the computer - Good eye Tom. Was that what the OP thought was dripping, but really silicone bubbles?
Great information guys. The water was dripping from the joint in the second picture and had formed a puddle on the floor. I am fairly confident that is wasn’t a puddle of silicone 
Silicone does leak - as many gals can attest to :twisted:
Anyway back to work - pretty much the leak is at the fitting that is improperly sealed with silicone sealant and not glue. Condensate - which is corrosive, forms as a natural by product of these efficiency heaters and is directed back to the heating unit via the vent to a condensate pump/ drain. So, the corrosive condensate ate away at the crappy silicone and is dripping instead of being routed back to the pump/ drain. Here is great foto for reference to use in future reports
It’s possible the condensate damaged the silicone but I’d say it was just an improper and poor attempt at sealing the pipes, probably done after the fact.
They should have been glued together and it looks like they may be slowly coming apart.
When I inspect vents off any gas burning heating equipment or water heater I always either give them a light shake or tap on them with the butt of my flashlight. It’s not uncommon for the pvc to be loose/unglued and metal vents to not be joined properly, i.e. no screws. And of course not supported well.
To me this is one of the most critical aspects of an inspection as a detached vent can lead to loss of life.
Recent photos, vent is unsupported, loose/no screws at joint and not sealed at chimney
Good practical advice Tom!