Could you also tell me if putting too large a capacitor would burn the pot? I accidentally a 10K pot. I put in a capacitor that I couldn't fully read the code. Maybe it was really big?

But no have more 10k in the mail! (eBay is the best)

Also, I plan to use multiple triacs in paralell to make a boiler heat control. (1000W) would this split up the l load? I don't have any 1000W triacs, I think the ones I have are 3A-5A, But can't find exact datasheet so I'm not sure.

As I check on google it is 30A 400V triac. Datasheets are there on google, how you are not finding it.
https://www.google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=q4003l3 datasheet
http://datasheets.globalspec.com/ds...onductor/72AD64D4-F708-4970-B928-AE874DA12260

As here in India it is google.co.in but you will get on .com too.

 

Just wanted to post an update: with 500K pot, and the original schematic (minus the led and diode), a 0.047 uF capacitor (573 code) works pretty well to give a full range, rated for 50V. (I used a 25V cap and it got busted) However, I ended up going with a lower value because since the control isn't linear, I wanted more precise control over the top 3/4ths. (I think I used 223 + 103 capacitor together)

Fan controller works great.

You can not use 25V capacitor as the breakover voltage of Diac D3 is 32V. S0 50V and above is ok. And capacitor value code 473 is 47x1000 pf = 47000/1000 nf = 47/1000 uf=0.047 uf. All these coded values are in pieco farad.