Question from user rbfking at hvacadvice at reddit.com.

Answer:

Do you have a multi-meter? Is there 24 to 28vac between the W and R terminals. If not, then you need to see if the furnace has 24vac at the R and C terminals. If it doesnt the furnace may not have power, or the transformer making the 24vac power may have failed.

A standing pilot can stay lit while the furnace loses power. Once the pilot light heats the thermopile, it will keep the pilot valve open indefinitely.

Answer from user kriegmonster at hvacadvice at reddit.com.

thermostat heat will not turn on pilot is on