implements PR shiptest-ss13#2977 heater layers

code/game/machinery/shuttle/shuttle_heater.dm

@@ -223,7 +223,14 @@
 	layer = OBJ_LAYER
 	showpipe = TRUE
 
-	pipe_flags = PIPING_ONE_PER_TURF | PIPING_DEFAULT_LAYER_ONLY
+	pipe_flags = PIPING_ONE_PER_TURF
+
+/obj/machinery/atmospherics/components/unary/shuttle/fire_heater/on_construction(obj_color, set_layer)
+	var/obj/item/circuitboard/machine/shuttle/fire_heater/board = circuit
+	if(board)
+		piping_layer = board.pipe_layer
+		set_layer = piping_layer
+	..()
 
 /obj/machinery/atmospherics/components/unary/shuttle/fire_heater/New()
 	. = ..()

code/game/objects/items/circuitboards/machine_circuitboards.dm

@@ -1508,12 +1508,24 @@
 
 /obj/item/circuitboard/machine/shuttle/fire_heater
 	name = "Combustion Engine Heater (Machine Board)"
+	desc = "You can use mulitool to switch pipe layers"
+	var/pipe_layer = PIPING_LAYER_DEFAULT
 	build_path = /obj/machinery/atmospherics/components/unary/shuttle/fire_heater
 	req_components = list(
 		/obj/item/stock_parts/micro_laser = 1,
 		/obj/item/stock_parts/matter_bin = 1
 	)
 
+/obj/item/circuitboard/machine/shuttle/fire_heater/attackby(obj/item/I, mob/user, params)
+	if(I.tool_behaviour == TOOL_MULTITOOL)
+		pipe_layer = (pipe_layer >= PIPING_LAYER_MAX) ? PIPING_LAYER_MIN : (pipe_layer + 1)
+		to_chat(user, "<span class='notice'>You change the circuitboard to layer [pipe_layer].</span>")
+		return
+
+/obj/item/circuitboard/machine/shuttle/fire_heater/examine()
+	. = ..()
+	. += "<span class='notice'>It is set to layer [pipe_layer].</span>"
+
 /obj/item/circuitboard/machine/shuttle/smes
 	name = "Electric Engine Precharger (Machine Board)"
 	build_path = /obj/machinery/power/smes/shuttle