Yes, you can claim 3 years work experience. There are 2 factors at play here. First is your eligibility for FSW and second is your CRS score for ITA purposes. They are basically independent from each other.
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To be eligible for FSW you need to have at least 1 year of continuous work experience under your primary NOC (1122 in your case) in the last 10 years. You have almost 3 years under NOC 1122, so you comply with the work experience requirement for FSW.
For the sake of your CRS score, you can include experience gained across multiple NOCs, including your primary in the last 10 years.