Tips to Maintain Your Boiler Pump
All boiler spares should be maintained to make sure that your combination boiler will last long. The way you take care for your boiler pump will become the basis on whether or not the pump’s operation will be continuous or intermittent.
To be able to take care of your pump boiler, you need to identify the required capacity that is needed to pump. The amount of water that you need to pump will depend upon the evaporation rate of the pump for boiler will service. A safe figure for an on-off application would be 2 times the evaporation rate of the combination boiler. With a modulating level control, a factor of 1.3 times the evaporation rate plus recirculation is recommended. This will ensure that the capacity of your combi pump is just right.
Note Your Desired Discharge Pressure
Once you pump directly into the heating boiler you will need to overcome the pressure in the boiler as well as any piping losses. This is to avoid problems with your boiler pumps. You can choose the right pump by looking at the pump curves to determine which will accomplish the task. Should you have a modulating valve in the discharge line; the minimum you will need to add to the combi boiler operating pressure will be 20 to 25 lbs. You need to make sure that the boiler pump can handle the pressure along with the flow rate needed. With an on-off level control the pumps should be designed for the relief valve pressure.
Net Positive Suction Requirement
This is the last piece of information that you will need to make sure that your boiler pump is in good condition. This is the minimum absolute pressure at the suction nozzle at which the pump can operate. To avoid combination pump cavitation, the NPSHA of the system must be greater than the NPSHR of the pump. This means that the available NPSH must be higher than what is required.