My furnace was only blowing cool air no heat at all. I contacted JDL heating service after checking there reviews. The technician Mr IRE Y was very knowledgeable and professional he diagnosed the problem and explained everything to me he also informed me that the parts needed was under warranty which was the circuit board and the gas valve so I only had to pay for labor. This was on Thanksgiving day so unfortunately he couldn't get the parts right away but as promised he got it done. Thank you Mr IRE Y