FMO | FM DESIGN | HVAC SYSTEMS MAINTENANCE EL

 

HVAC&R SYSTEMS MAINTENANCE

FM SYSTEM DESIGN

ASHRAE Handbook “HVAC Applications”, defines repair as to make good or to restore to good or sound conditions and, defines service as what is necessary to effect a maintenance program short of repair.

HVAC&R maintenance is: “the part and labor” costs, required to maintain or restore HVAC&R systems to condition such that they can be effectively operated to meet specified performance.

 

In the ASHRAE Handbook, maintenance also is classified into the following categories:

1.     Run to failure: a kind of arrangement such that no money is spent on maintenance prior to equipment or system breakdown.

2.     In planned maintenance: all functions and resources in this category must be planned | budgeted | scheduled. Can be divided:

a.     Preventive action: a kind of scheduled maintenance for an HVAC&R system, equipment or components in order to maintain durability – reliability – efficiency and safety.  

b.     Corrective action: is often the remedial action performed before failure occurs. In case it happens during a shutdown in response to a failure is called a repair.  

3.     Predictive maintenance: is based on equipment and systems monitoring the operating conditions and performance to discover faults and degradations and thus the remedy performed.

 

 

Most manufacturers give detailed instructions in how to operate and maintain the specific equipment and instruments. These instructions must be followed.

 

Maintenance Contractors and Maintenance Personnel

In most small facilities with comparatively simple HVAC&R systems outside maintenance contractors often provide maintenance service based on the specified maintenance program.

The time interval between two maintenance programs depends on the operating hours of the HVAC&R system, that is:

1.     Dirt accumulation the filters.

2.     Coils.

3.     Distribution devices.

4.     Recalibration requirements of the instruments.

For small and complicated HVAC&R systems whenever the operator cannot repair and service the system, the Owner or the facility manager should ensure that qualified contractors are hired for maintenance.

For more complicated medium sized multizone systems operating personnel are often responsible for HVAC&R. The maintenance programs should de detailed in the O&M manual and tailored to each specific building. For high technical equipment and systems an outside maintenance contractor with the specific expertise required should be called for service.

For large HVAC&R systems with central plants, a management organization with one operations person and one maintenance person is required. Computerized maintenance programs should be used to provide detailed timing of system maintenance procedures.

Logged information and proper data management associated with predictive maintenance will reduce failure response requirements. An outside maintenance service contractor with specific expertise may need to be called.

  

Monitoring and Fault Detection and Diagnostics Assisting Predictive Maintenance

Faults occur when the actually measured parameters deviate from the normal operating values.

Performance degradation is an evolving fault accumulated during a certain period of time.

By using:

a.     Rule-based expert systems, &

b.     Autoregressive with exogenous inputs, &

c.      Artificial neural network models,

then Performance degradation and faults can be determined.

HVAC&R maintenance is an important part to improve IAQ and to maintain a safe, healthy and comfortable indoor environment.