go to the hwh website. you can download, or look at their current service manual and PARTS manual. almost everything that hwh uses in their systems is shown in detail in the parts manual. some parts are sold as assemblies only.
any part that is not broken down with separate part numbers is sold as an assembly only, mostly because there are settings, adjustments, or torque values within the part that must be maintained. if you have problems after that, please contact me,
pfmaddox@att.net. i work for hwh as a rep in arizona. i will be happy to help.