Every time the furnace fires up, it blows out the pilot light. Sometimes it will run a full cycle and blow out when it shuts down, and sometimes it will blow out about a minute into the cycle.
We had a tech at the house yesterday for a different furnace issue, and unfortunately, nobody was home when he came. From what we can tell, he changed some of the copper lines going into the furnace and he did remove the air filters.
When we got home the furnace was running fine, but after a couple of cycles it started acting up. We relight the pilot with no problem, but as I said as soon as it starts running, it blows the pilot out.
Could the lack of air filters be the problem, or do I need to call the tech back to the house?