The first thing is that a transformer is really easy to replace, two screws and two wire nuts that connect the wires. Look at how the old one went in , and put the new one in the same way. Secondly, Unfortunately the transformers are warranted from the manufacturer for 30 days. If the last new transformer did not fix the problem, I would check to make sure that it is getting power, something that any good mechanic would do before replacing it. It is simple to do with a test light,(About $6 at an auto parts store) Ground the clip and touch the wire on the hot side of the transformer. If the light is coming on, it is a transformer problem. If it is not, I would check the pressure switch, ( a little black box off of the unloader, that big brass thing by the pump), and check it. If it has no power, check the temp switch, which is usually right by the quick connect coming out od the heater. Before you do all of that, I would check the fuse. There are two places that it could be, one is comin goff of the right side of the engine where all of the wires are, and if it is not there, flip open the transformer, (really an ignitor) and see if it is there. By the way, for $175 plus parts, I hope the guy bought you flowers, and took you out to dinner. To do all of this takes me about 5-10 minutes. Replacing the ignitor is another 3-4 minutes.