I had a similar issue with a new human reg on filling VERY slow set at at 170 bar. I contacted Huma-Air and found out that there had been a revision on the number of Belleville washers that are installed for that regulator (1155). Mine came with nine and the instructions showed to use all nine. Huma-Air later revised that to 8 washers and I tried it and it now it works perfectly. I think they had switched to a thicker Belleville washer so only eight would fit to work correctly and I was trying to use nine per the old instructions that came with it using the thicker washers.
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