Pactrol Box 4049 S ref 404901

_l}_{,CTROL I:JRODUCT SPECIFICATION NO. 4049S ;\utom;:itic Gas Contol Type 4049S IJescription The 4049S control unit provides for automatic ignition and safe supervision of a single or two stage gas burner , operating with !\ . C . va 1 ves. The unit is suitable for use in a single burner appliance or, when combined with other units, will provide the basis for .:1 multiburner control system. The start-up sequence can either be initiated by a manually operated switch mounted on the control housing or by an automatic process inter­ lock such as a thermostat. The control begins its sequence by checking that the flame detector is signalling 'no-flame' while proceeding through a prepurge or wait period. The internal , high voltage spark generator is then energised together with the first stage gas valve terminal. The spark and valve will remain energised until the gas is lit or the ignition safety period is completed. When the gas is lit the flame is detected either via a flame probe or by a Pactrol U.V. monitor cau�ing the spark generator to be de-energised but maintaining the first stage gas vàlve open. As the spark goes off , the second stage gas valve terminal is energised and bath valves remain energised until the electrical supply to the unit is removed or the flame goes out. If the gas fails to ignite or the flame subsequently fails , the gas valve(s) will automatically be de-energised and the control unit will go into a state of lockout. Reset of the lockout condition followed by a new start-up sequence can only be achieved by interrupting the electrical supply to the unit for a minimum of 3 seconds. Single Probe Operation A conventional two electrode system can be use4 with this control unit to provide seperate ignition and detection of a gas burner flame. However, where the main burner is lit by the spark at a full or reduced rate the control can provide iimultaneous ignition and detection of the flame using only one electrode. The electrode should be where possible position�d to take advantage of the earthed metal of the burner or its combustion chamber. This feature is obtained by sirnply linking terrninals 1 and 7 together and connecting the single probe to terminal 15. This feature has particular advantages where space is limited and only one electrode can be fitted. The use of the single probe facility also reduces the cost of installation and servicing. Note: to measure the probe current during single probe operation a sensitive ammeter ( should be connected in place of the link. 1. 1 ,! :,