What is the difference between the 14004904-002 and the /U version

Smith water heaters and Lochinvar heating units

ensuring both durability and optimal airflow for rapid thermal response

Check for a temperature differential of more than 3°F between the permanent suction line and the suction line from the evaporator

a dedicated multi-stage controller is required

Fenwal 35-605501-003 Control Els PW 17895 What is the difference betweenThe Fenwal 35 605501 003 is a microprocessor based Direct Spark Ignition (DSI) control engineered for precision timing and reliable burner operation in gas fired appliances. This 24VAC module features a single trial ignition sequence (1 try) with a 7 second trial for ignition (TFI) and a 0 second pre purge, making it an ideal choice for systems requiring immediate spark response. Built for heavy duty HVACR applications, it utilizes DETECT A FLAME