I was working as a professional for a Dor-Mar Heating & Air Conditioning company. I was called to a customer's home to check out a furnace that was not working. I arrived at the customer's home and found that the furnace was not firing and the gas pressure was low. I checked the furnace and found that the gas valve was not opening. I replaced the gas valve and the furnace fired right up. I tested the gas pressure and it was now at the correct level. The customer was very happy with the service and thanked me for my help.