Identify the unit and the failing function

Record the manufacturer, model and serial details from the equipment label, the observed symptom and the fan speeds at which it occurs. A technician should check relevant electrical and mechanical causes using the unit's service information. A noise near a grille, a control fault and a motor fault can lead to different scopes. Do not order a part from a photo of a similar FCU.

Compare two complete proposals

Motor route: exact part and compatibility basis; access and labour; any associated components; checks after installation; and what remains uncertain about the older unit.

Whole-unit route: unit dimensions and connections; ceiling removal and making good; controls, drain and duct interfaces; installation checks; and disposal of the old unit. The larger scope may depend on a site survey and building approvals.

In an Arabian Ranches record (12751), the team planned plenum and grille work and considered motor replacement if the sound returned. That was a conditional option, not a recorded motor replacement or a proven saving. Separate a provisional idea from a confirmed diagnosis in your own quotation.

Choose only after the provider explains why the proposed part fits the identified model and which other faults remain open. Ask how performance will be checked at the operating modes that originally showed the problem. A brief quiet run alone does not establish the condition of every part of the FCU.