Scope

This document provides instructions for servicing components of HC and HCS thermal fluid heaters (Fig. 1 and 2 ). The components covered are mainly those that can cause heater malfunctions when they go bad, need cleaning, or get out of adjustment.

These instructions provide remedies to problems covered in a troubleshooting guide that is a separate Tec-Note. Routine maintenance and lubrication instructions are also provided in separate Tec-Notes. Because of differences in heaters, some instructions may not apply to your heater.

Intended users

Instructions in this document are intended for use by qualified asphalt plant operators and maintenance personnel. Qualified persons are those who understand electrical shock hazards and how to avoid them. Such persons are also familiar with the burn hazards of working with liquid asphalt and thermal fluids heated to temperatures in excess of 300 degrees F.

Some procedures require setting and testing parts inside the heater electrical control panel while it is open and electrical power is turned on. This should be done only by qualified persons using electrical testers to make sure wires and terminals they may accidentally touch are deenergized so that no electrical power is present.

Figure 1. HC heater with manifold and side pumps.

Figure 2. HCS single circuit heater.

Figure 4. Opening and closing valves.