need to replace rain cap, water is getting in

[Amaralluis]

Im not using my stove as much and I have a problem that I never had before. The raincap is not preventing water from coming from the inside the vent. I am not sure why, but I want to replace with a new cap that will prevent water from coming in.
I was wondering if this was cap was a good one?

http://www.homehardware.ca/en/rec/index.htm/_/N-ntimt/Ne-ntc74/R-I5512509?Num=1

 

[smoke show]

maybe use something pellet specific.
that looks to be a gas vent type cap?

 

[Amaralluis]

Ths is the cap that I have:

http://www.homehardware.ca/en/rec/index.htm/_/N-67lZ2pqf/Ne-67n/Ntk-All_EN/R-I5533026?Ntt=pellet

For some reason now the water gets in. It leaks at the bottom of the T vent, and the T cap is full of water, I have checked and rechecked and the water comes from inside the vent so the problem is the cap.
I went on the roof yesterday and made sure it was level which it wasnt, maybe that was the issue, but because I dont use the stove as much I want to get a better cap to prevent rain coming in.