Do you use EN 12953 (intended for fired or electric boilers) as part of the conformity assessment process for higher-pressure unfired steam generators? (EN 13445 is not directly applicable due to 110C scope limitation).
If your device is unfired (do you maybe have some sort of sketch?) I'd be tempted to think this is more of an EN 12952 application, since 12953 is for fired equipment I think.