Sometimes getting the "HED Error" message can be a dirty HED assembly. The cleaning process for the HED assembly is recommended when the GCMS has high noise background or spiking with the HED on. This can happen if there are any particles on the metal surfaces of the HED or the bare metal wire inside. It can occur anytime you open and close the analyzer. Most times a gentle puff of the gas out of a can of air duster is sufficient to dislodge any particles. If that doesn’t work here are the next steps. (it is a consumable item and not covered under Service Contracts).
This cleaning should certainly be attempted before thinking about replacing it. Wear latex or nitrile gloves – you want to avoid any dust or particulates coming off fabric ones. The HED and the EM are customer replaceable consumable parts.