it works

code/game/objects/items/RPD.dm

@@ -25,7 +25,7 @@ GLOBAL_LIST_INIT(atmos_pipe_recipes, list(
 	"Devices" = list(
 		new /datum/pipe_info/pipe("Connector",			/obj/machinery/atmospherics/components/unary/portables_connector),
 		new /datum/pipe_info/pipe("Unary Vent",			/obj/machinery/atmospherics/components/unary/vent_pump),
-		new /datum/pipe_info/pipe("Gated Valve",		/obj/machinery/atmospherics/components/binary/gated_valve),
+		new /datum/pipe_info/pipe("Relief Valve",		/obj/machinery/atmospherics/components/unary/relief_valve),
 		new /datum/pipe_info/pipe("Gas Pump",			/obj/machinery/atmospherics/components/binary/pump),
 		new /datum/pipe_info/pipe("Passive Gate",		/obj/machinery/atmospherics/components/binary/passive_gate),
 		new /datum/pipe_info/pipe("Volume Pump",		/obj/machinery/atmospherics/components/binary/volume_pump),

code/modules/atmospherics/machinery/components/unary_devices/relief_valve.dm

@@ -1,8 +1,9 @@
 /obj/machinery/atmospherics/components/unary/relief_valve
 	name = "pressure relief valve"
 	desc = "A valve that opens to the air at a certain pressure, then closes once it goes below another."
-	icon = 'icons/obj/atmospherics/components/unary_devices.dmi'
+	icon = 'icons/obj/atmospherics/components/relief_valve.dmi'
 	icon_state = "relief_valve-e"
+	can_unwrench = TRUE
 	var/opened = FALSE
 	var/open_pressure = ONE_ATMOSPHERE * 3
 	var/close_pressure = ONE_ATMOSPHERE
@@ -19,11 +20,10 @@
 	pixel_y = PIPING_LAYER_P_Y
 
 /obj/machinery/atmospherics/components/unary/relief_valve/atmos
-	var/close_pressure = ONE_ATMOSPHERE * 2
+	close_pressure = ONE_ATMOSPHERE * 2
 
 /obj/machinery/atmospherics/components/unary/relief_valve/atmos/atmos_waste
 	name = "atmos waste relief valve"
-	id =  ATMOS_GAS_MONITOR_WASTE_ATMOS
 
 /obj/machinery/atmospherics/components/unary/relief_valve/update_icon_nopipes()
 	cut_overlays()
@@ -34,7 +34,7 @@
 
 	icon_state = "relief_valve-e-blown"
 
-/obj/machinery/atmospherics/components/unary/outlet_injector/process_atmos()
+/obj/machinery/atmospherics/components/unary/relief_valve/process_atmos()
 	..()
 
 	if(!is_operational())
@@ -44,12 +44,14 @@
 	var/our_pressure = air_contents.return_pressure()
 	if(opened && our_pressure < close_pressure)
 		opened = FALSE
+		update_icon_nopipes()
 	else if(!opened && our_pressure >= open_pressure)
 		opened = TRUE
+		update_icon_nopipes()
 	if(opened && air_contents.temperature > 0)
 		var/datum/gas_mixture/environment = loc.return_air()
 		var/pressure_delta = our_pressure - environment.return_pressure()
-		var/transfer_moles = pressure_delta*environment.volume/(air1.temperature * R_IDEAL_GAS_EQUATION)
+		var/transfer_moles = pressure_delta*200/(air_contents.temperature * R_IDEAL_GAS_EQUATION)
 		if(transfer_moles > 0)
 			var/datum/gas_mixture/removed = air_contents.remove(transfer_moles)
 
@@ -57,3 +59,53 @@
 			air_update_turf()
 
 			update_parents()
+
+/obj/machinery/atmospherics/components/unary/relief_valve/ui_interact(mob/user, ui_key = "main", datum/tgui/ui = null, force_open = FALSE, \
+																datum/tgui/master_ui = null, datum/ui_state/state = GLOB.default_state)
+	ui = SStgui.try_update_ui(user, src, ui_key, ui, force_open)
+	if(!ui)
+		ui = new(user, src, ui_key, "atmos_relief", name, 335, 115, master_ui, state)
+		ui.open()
+
+/obj/machinery/atmospherics/components/unary/relief_valve/ui_data()
+	var/data = list()
+	data["open_pressure"] = round(open_pressure)
+	data["close_pressure"] = round(close_pressure)
+	data["max_pressure"] = round(MAX_OUTPUT_PRESSURE)
+	return data
+
+/obj/machinery/atmospherics/components/unary/relief_valve/ui_act(action, params)
+	if(..())
+		return
+	switch(action)
+		if("open_pressure")
+			var/pressure = params["open_pressure"]
+			if(pressure == "max")
+				pressure = MAX_OUTPUT_PRESSURE
+				. = TRUE
+			else if(pressure == "input")
+				pressure = input("New output pressure (0-[MAX_OUTPUT_PRESSURE] kPa):", name, open_pressure) as num|null
+				if(!isnull(pressure) && !..())
+					. = TRUE
+			else if(text2num(pressure) != null)
+				pressure = text2num(pressure)
+				. = TRUE
+			if(.)
+				open_pressure = CLAMP(pressure, 0, MAX_OUTPUT_PRESSURE)
+				investigate_log("open pressure was set to [open_pressure] kPa by [key_name(usr)]", INVESTIGATE_ATMOS)
+		if("close_pressure")
+			var/pressure = params["close_pressure"]
+			if(pressure == "max")
+				pressure = MAX_OUTPUT_PRESSURE
+				. = TRUE
+			else if(pressure == "input")
+				pressure = input("New output pressure (0-[MAX_OUTPUT_PRESSURE] kPa):", name, close_pressure) as num|null
+				if(!isnull(pressure) && !..())
+					. = TRUE
+			else if(text2num(pressure) != null)
+				pressure = text2num(pressure)
+				. = TRUE
+			if(.)
+				close_pressure = CLAMP(pressure, 0, MAX_OUTPUT_PRESSURE)
+				investigate_log("close pressure was set to [close_pressure] kPa by [key_name(usr)]", INVESTIGATE_ATMOS)
+	update_icon()

code/modules/atmospherics/machinery/datum_pipeline.dm

@@ -227,11 +227,6 @@
 				if(V.on)
 					PL |= V.parents[1]
 					PL |= V.parents[2]
-			else if (istype(atmosmch, /obj/machinery/atmospherics/components/binary/gated_valve)) // i hate this
-				var/obj/machinery/atmospherics/components/binary/gated_valve/V = atmosmch
-				if(V.cur_open)
-					PL |= V.parents[1]
-					PL |= V.parents[2]
 			else if (istype(atmosmch, /obj/machinery/atmospherics/components/unary/portables_connector))
 				var/obj/machinery/atmospherics/components/unary/portables_connector/C = atmosmch
 				if(C.connected_device)

tgstation.dme

@@ -1461,7 +1461,6 @@
 #include "code\modules\atmospherics\machinery\components\binary_devices\binary_devices.dm"
 #include "code\modules\atmospherics\machinery\components\binary_devices\circulator.dm"
 #include "code\modules\atmospherics\machinery\components\binary_devices\dp_vent_pump.dm"
-#include "code\modules\atmospherics\machinery\components\binary_devices\gated_valve.dm"
 #include "code\modules\atmospherics\machinery\components\binary_devices\passive_gate.dm"
 #include "code\modules\atmospherics\machinery\components\binary_devices\pump.dm"
 #include "code\modules\atmospherics\machinery\components\binary_devices\valve.dm"
@@ -1473,6 +1472,7 @@
 #include "code\modules\atmospherics\machinery\components\unary_devices\heat_exchanger.dm"
 #include "code\modules\atmospherics\machinery\components\unary_devices\outlet_injector.dm"
 #include "code\modules\atmospherics\machinery\components\unary_devices\portables_connector.dm"
+#include "code\modules\atmospherics\machinery\components\unary_devices\relief_valve.dm"
 #include "code\modules\atmospherics\machinery\components\unary_devices\tank.dm"
 #include "code\modules\atmospherics\machinery\components\unary_devices\thermomachine.dm"
 #include "code\modules\atmospherics\machinery\components\unary_devices\unary_devices.dm"

tgui/src/interfaces/atmos_relief.ract

@@ -0,0 +1,12 @@
+<ui-display>
+	<ui-section label='Open Pressure'>
+		<ui-button icon='pencil' action='open_pressure' params='{"open_pressure": "input"}'>Set</ui-button>
+		<ui-button icon='plus' state='{{data.open_pressure == data.max_pressure ? "disabled" : null}}' action='open_pressure' params='{"open_pressure": "max"}'>Max</ui-button>
+		<span>{{Math.round(adata.open_pressure)}} kPa</span>
+	</ui-section>
+	<ui-section label='Close Pressure'>
+		<ui-button icon='pencil' action='close_pressure' params='{"close_pressure": "input"}'>Set</ui-button>
+		<ui-button icon='plus' state='{{data.close_pressure == data.max_pressure ? "disabled" : null}}' action='close_pressure' params='{"close_pressure": "max"}'>Max</ui-button>
+		<span>{{Math.round(adata.close_pressure)}} kPa</span>
+	</ui-section>
+</ui-display>