Furnace not working

We're not sure why, but the furnace hasn’t been working all day. We changed the filter and re-lit the pilot this morning, but it still isn't blowing warm air. 

condo townhouse，可能会是什么问题？得找人吧？怎么修？谢谢

所有跟帖： 

• 这肯定得找人啊？估计是主板线路老化得换 -thankful- ♀ (0 bytes) () 11/22/2020 postreply 15:05:48

• 开机后，火起来了吗？风扇吹了吗？有个闪烁的灯给你error code。对照一下门后的表，就能知道问题是啥 -新手地主刚上路- ♂ (0 bytes) () 11/22/2020 postreply 17:34:23

• 昨天furnace无缘无故地恢复正常工作，今天租客又说不工作了。 -she3652003- ♀ (0 bytes) () 11/23/2020 postreply 06:54:50

• 火起来了，风扇和风扇都开了,但是现在只有67度（设了72度） -she3652003- ♀ (0 bytes) () 11/23/2020 postreply 06:56:23

• Tenant's response -she3652003- ♀ (309 bytes) () 11/23/2020 postreply 07:03:54

• Clean the flame sensor. See if it helps. Search YouTube video re -在水四方- ♀ (0 bytes) () 11/23/2020 postreply 10:29:23

• Thank you. -she3652003- ♀ (0 bytes) () 11/23/2020 postreply 17:28:31