I read a few posts about my combi boiler issue, familiarised myself with the service manual & proceeded to remove the wrong heat exchanger (primary). I didn't know that there were two of them & now that I've managed to get it back together I've now got a serious leak from the primary heat exchanger. I'm guessing it's coming from the inlet & outlet as there doesn't appear to be any seals present. I added a couple of o rings I had but they don't seem to do the job as it continues to leak after a while. I was just wondering if anyone had any advice as to how I can seal this up once and for all?