Coal Stoker Holdfire Timers | JONMAR GEAR MACHINE INC.
WEBCoal Stoker Holdfire Timers. The WillBurt model 34170 Holdfire Timer provides periodic stoker operation during mild weather and other times when the system operating controller does not demand burner operation, in order to. maintain combustion, so that the fire does not have to be frequently restarted, and; prevent the fuel bed from burning down into, .