This Suntec Pump is specially modified and cannot be replaced without getting it from INOV8. The pump is used directly on the burner motor and acts as a vacuum pump because of the modifications. That means it is self priming. It is also an integral component of the patented oil preheating system which moves the oil in small tubes around the heating element at four feet per second. That velocity prevents charring of the oil that is common in slower methods. The model numbers used are A2RA-7736, A2RA-7737 and A2RA-7747. They differ by the spring inside which adjusts the pump pressure. We modify all to have the accurate spring.