BB Witbier Kit - Low OG

I have been lurking the forums for awhile now and first want to say thanks for all the knowledge that I have gained.

I started brewing about a year ago with a BB equipment kit and have brewed about 6-7 different BB extract kits since. I felt comfortable doing this so I decided to read up on partial mash (don't have the space for a all-grain setup). I went to the LHBS and asked around about partial mashing. I found out the owner was actually having a class in a few weeks for all-grain and he told me a lot of the concept for a partial could be learned there. To save my self from possible screw up I decided to stick with what I knew until I could take the class and I picked up the BB Witbier kit.

I get home and started reading the directions and come to find out this kit is a "steep-to-convert" kit. Which to me reads partial mash (could be wrong). I was worried but excited at the same time since it was a kit, but allowed me to partial mash. I followed the instructions of converting the 2lbs of grains (1lb pale malt, .5lb wheat, and .5lb oats) at 148-154 degrees in a gallon of water for 45 minutes (Was pretty good about keeping it in the temp range) and continued on with the boil and got it cooled down ready to pitch.

I took the gravity using my new refractometer I got for Christmas and it read a gravity of 1.020. According to the BB directions I should of been atleast an OG of 1.045. My question is, did I screw something up in the converting that I didn't get all the sugars? Something else that gave me such a low gravity? I pitched and its currently sitting in my closet doing its thing.

TLDR; "Steep-to-convert" kit OG should of been 1.045 but got 1.20, what could of gone wrong?

Did you top off after your boil? If so, might be from incomplete mixing. Also, did you calibrate your refractometer? Mine was 15 points off when I received it.

Most likely that you didn't get complete mixing of the wort. This is pretty common.

Now that you have done a "steep to convert' you can see how easy this is. All grain isn't really much harder nor does it necessarily take more space. Search this forum for BIAB and you will see that what you did was essentially the same with smaller quantity. If you can boil 3 gallons of water on your stove, you can make a 3 gallon batch right in your kitchen. I've done 4 this way to learn the process and then to make a batch where I didn't want the full 5 gallons. I love it for when I have time to brew but it is 30 below and windy outside.

Yea, I calibrated and also had a buddy calibrate it before and after initial readings just to be sure.

Also I did top off after the boil, so sounds like a incomplete mixing then. Thanks guys appreciate the responses

this question gets posted about 47 times a day... i don't need to read your post to tell you that you did a partial boil, topped off and got a lower than expected OG, right? you didn't mix your top off water enough, which is fine, fermentation will do that for you. but next time, mix the water more thoroughly to ensure that your wort is properly aerated before you pitch.