I started the furnace for the first time this morning. It took me a while to notice i wasn't getting heat.

I reset the flame rollout switch and it appears to be fine.

Burner looks good through the site glass.

Should I be concerned? Should I have someone come out and look at it?

I guess I would wait and see if you have any more issues.

I had a new hot water heater installed about 2 weeks ago and they had to turn off gas to the house. I wonder if this had something to do with it?

I'm keeping a close eye on it. It's heating well and the flame looks good.

A roll out switch is a temp sensor near the burners. It s job is to trip and prevent flame roll out in front of burners due to possible flue blockage or other causes. Gas disruption should not cause it to trip. To be sure there is not a safety issue your furnace and venting should be checked.

I read that low gas pressure could cause this. That's what made me think about the gas being turned off recently.

I'm keeping a close eye on it.

Charles, When would you feel comfortable it was just a fluke?

Propane furnaces can be affected by low pressure, but, usually there is a low pressure switch in the gas line before the gas valve to prevent it. Also, depends if furnace is vented by a inducer (motor) or is atmospheric (chimney) draft. Inducer problem or chimney blockage are examples of restricted or poor venting that can cause roll out switch to trip. Any gas should be a steady pressure, so a steady flow through the gas valve and burners, whether gas or venting air. So, no back flow from burners if venting is proper. If, there is an issue , the roll out will trip again. How long that will take is unknown.

Also, a blockage in the heat exchanger can cause roll out to trip.

It sounds like I should have someone come to take a look at it.

For safety sake, I recommend it.

if you have air in the lines it can take a few tries to get enough through it at start up to purge the line

when I installed my hot water heater it is the forced exhaust type , about 4-5 times turn it on let it try to start before it finally did that first time been fine since

Failed ignition due to air in the gas lines does not cause the roll out to trip, it only causes unit to cycle until air is purged. Your forced exhaust makes that happen.

I saw where the OP said he reset the roll out switch, but I never saw him say it was tripped.

You know...I can't say for sure that it was tripped. When I pressed the button, it didn't seem to do much. But, the LED blinks said it was the flame rollout switch. I pressed the button. Then the thing started and ran fine ever since.

The house it a lot warmer than I'd like it to be.