Here's your model on Amazon with 16GB installed so it looks like it supports it.
 
https://www.amazon.co.uk/HP-15T-K100-i7-4710HQ-Speakers-Subwoofers/dp/B00ZD695NE
 
It also states that 16GB is the maximum capacity.
 
AMB
 

Thanks. I've seen a few models that also indicate this, but never my product. I had a look at the reviews, as there was only 2. This first two sentences could have been written by me.
"In less than 3 months I had to buy a new charger. And now, after 6 months only the battery doesn't charge."
Although the battery does charge, but windows says it doesn't

Mixing RAM type invites compatibility issues.
Absolutely make sure to have matching RAM sticks.

Hi Kamikaze,
I've got an HP which I recently updated the RAM on. I had exactly the same headache as you.
The HP site didn't list my model. Crucial told me I needed a particular speed of RAM (which I bought only to find it wasn't compatible). Don't trust the Crucial scanner....it doesn't give correct results.
In the end, the guys on the HP support site game me the best advice.
HP models can be particularly picky with RAM types. Make sure you use the same type as is installed (DDR2, DDR3 etc..) and the same speed. G-Skill is a brand of RAM which works with HP. I bought it and it worked on mine, and many people on the HP site said it worked with their laptops.
If in doubt, as an Expert on the HP site.
BTW: I'm running 6GB or RAM (one 2GB+4GB) of different brands, and I don't seem to have any problems.
Having said that, I am going to get a matching stick very soon, to bump mine up to 8GB.

Part of the issue is HP/Compaq is showing that to be a Config To Order (CTO) system. It will have a blanket top tier model but not a unique specific model number for your machine. Try checking the warranty with the serial and see what model it returns. If the warranty check requires you to enter a model# just enter AAAAA - 5 or 6 A's (whatever the site requires). If you get a valid return, it will show the actual model# for you to use.
 
Even at that though, don't be surprised to find inconsistencies. It has been said that Compaq is not really sure exactly what parts were installed as they source and use the lowest priced parts on a weekly basis.
 
If you want to PM your serial and the suspected model number I will see what I can find. I have quite a bit of experience with the compaq site and can use a vendor login if needed.

Yeah, I've exhausted the site options, and searches.
 
I'm just going to buy a pair, and put the existing 8gb in my new work laptop, in place of it's 2gb