Hermetically sealed, self-lubricating pumps should never be oiled or lubricated. It is not only unnecessary, but could also damage the pump. Very little maintenance is required for these pumps.
Sometimes the failure of a hot-water (hydronic) heating system to produce heat can be traced to a malfunctioning circulator (pump). Before attempting to repair or replace the unit, check the electric power to the pump from the system controls. The problem may be due to an electrical failure, instead of the mechanical failure of the pump itself. Always first check for a blown fuse or a tripped circuit breaker.
If repairs are required, manufacturers commonly provide parts lists for their pump models so that the unit can be serviced on site. For the circulator shown in Figure 10-16, it is possible to replace the shaft sleeve, seals, gaskets, and impeller (all parts subject to wear) without removing the pump from the piping.
The pH value of the water is an important consideration when operating circulators. For optimum operation, the water should have a pH ranging from 7 to 9. The water pH value can change during the service life of the pump. These changes occur as a result of a change in water quality or chemical additives. If the pH value of the water falls outside the 7–9 range, it can cause circulator seal failure or corrosion of system components.
Important Safety Tips
• To avoid possible injury or even death from electrical shock, always shut off the electrical power and disconnect the pump before attempting to service or repair it.
• To avoid scalding burns, always allow the system water to cool to room temperature before attempting to remove a pump for servicing.