Although an easy-to-forget component in a thermal fluid heating system, the expansion tank is vitally important to reliable system operation.
The expansion tank is a very important and oft-ignored component of the thermal fluid system.
Most owners pay attention to the other components in the thermal fluid system. They maintain the combustion system on the heater, maintain alignment and mechanical seals on pumps, maintain instrumentation and control valves, and inspect heat exchangers. They may even have their thermal fluid tested regularly, but because it is a static piece of equipment, these same people often neglect the expansion tank.
In my consulting practice, I often visit sites where there are complaints centered on startup difficulties and fluid degradation problems. On one visit, when I asked to take a look at the expansion tank, it took about 15 minutes to find it! When we did find the expansion tank, it was obvious that no one had paid attention to this piece of equipment for a long time. It was no wonder that this facility was having problems.