Figure 6
Note: this is just an example of the kind of circuits that will be found and, in all cases, refer to the OEM wiring.
Another thing to consider are the purges or‘ delays’. With many residential applications today these purges or delays are also referred to as‘ valve-on delay’( pre-purge) and‘ motor-off delay’( post-purge). Today you can buy many oil primary controls and gas ignition modules that will give you a guaranteed pre-purge cycle every time which creates a nicely controlled, delayed start-up of the burner. You get constant air proving directly through that air switch and are assured of a good air flow through the appliance and venting system.
The last thing to consider is a postpurge cycle that will give you a controlled delayed shut down of the burner fan and inducer. How do you get all these great features? Well, you could install a programmer, but if you thought I had a lot of expensive equipment on the table so far, wait until you see how many hundred dollar bills you need to buy a programmer!
With a modern gas system, the appliance may already have a control, Figure 7, and wiring and be ready to accept an inducer that will work in conjunction with the ignition system module. However, with many conversions from oil to gas and the possibility of an even lower stack temperature( producing even less thermal draft) an
Figure 7
inducer may be required and so the inducer controller becomes the solution for many jobs. With an oilburner, there are many controls available that can work with an inducer control that can provide timed purges that will correct even the most difficult problems. Using the right control always does the trick and that brings us to our final control.
In Figure 8 is a Carlin 70200 also known as a ProX with its burner wiring shown in Figure 9. By using this control and the correct terminals you can have all the functionality of a purging oilburner primary with full control of your draft inducer. Rather than using a controller( like that shown in Figure 6) you would run two wires from your inducer proving switch to your primary. The two wires for your proving switch would go between the terminals marked BV-BV, Figure 10. The two wires for your inducer motor would go across the terminals marked MOTOR and L2 in parallel with your burner motor. Using the programming in the
Figure 8
Figure 9
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