diff --git a/default_settings.lua b/default_settings.lua
index 91e511c..9aa4835 100644
--- a/default_settings.lua
+++ b/default_settings.lua
@@ -27,6 +27,8 @@ local settings = {
 	drop_on_routing_fail = false,
 
 	delete_item_on_clearobject = true,
+
+	enable_new_flow_logic = false,
 }
 
 for name, value in pairs(settings) do
diff --git a/devices.lua b/devices.lua
index 0121e2f..3b7fc78 100644
--- a/devices.lua
+++ b/devices.lua
@@ -68,7 +68,7 @@ function pipeworks.rotate_on_place(itemstack, placer, pointed_thing)
 			local placednode = string.gsub(itemstack:get_name(), "_loaded", "_empty")
 			placednode = string.gsub(placednode, "_on", "_off")
 
-			minetest.add_node(pos1, {name = placednode, param2 = fdir })
+			minetest.swap_node(pos1, {name = placednode, param2 = fdir })
 			pipeworks.scan_for_pipe_objects(pos1)
 
 			if not pipeworks.expect_infinite_stacks then
@@ -149,16 +149,17 @@ for s in ipairs(states) do
 		drop = "pipeworks:pump_off",
 		mesecons = {effector = {
 			action_on = function (pos, node)
-				minetest.add_node(pos,{name="pipeworks:pump_on", param2 = node.param2}) 
+				minetest.swap_node(pos,{name="pipeworks:pump_on", param2 = node.param2})
 			end,
 			action_off = function (pos, node)
-				minetest.add_node(pos,{name="pipeworks:pump_off", param2 = node.param2}) 
+				minetest.swap_node(pos,{name="pipeworks:pump_off", param2 = node.param2})
 			end
 		}},
 		on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
 			local fdir = node.param2
-			minetest.add_node(pos, { name = "pipeworks:pump_"..states[3-s], param2 = fdir })
+			minetest.swap_node(pos, { name = "pipeworks:pump_"..states[3-s], param2 = fdir })
 		end,
+		-- FIXME - does this preserve metadata? need to look at this
 		on_rotate = screwdriver.rotate_simple
 	})
 	
@@ -188,15 +189,15 @@ for s in ipairs(states) do
 		drop = "pipeworks:valve_off_empty",
 		mesecons = {effector = {
 			action_on = function (pos, node)
-				minetest.add_node(pos,{name="pipeworks:valve_on_empty", param2 = node.param2}) 
+				minetest.swap_node(pos,{name="pipeworks:valve_on_empty", param2 = node.param2})
 			end,
 			action_off = function (pos, node)
-				minetest.add_node(pos,{name="pipeworks:valve_off_empty", param2 = node.param2}) 
+				minetest.swap_node(pos,{name="pipeworks:valve_off_empty", param2 = node.param2})
 			end
 		}},
 		on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
 			local fdir = node.param2
-			minetest.add_node(pos, { name = "pipeworks:valve_"..states[3-s].."_empty", param2 = fdir })
+			minetest.swap_node(pos, { name = "pipeworks:valve_"..states[3-s].."_empty", param2 = fdir })
 		end,
 		on_rotate = pipeworks.fix_after_rotation
 	})
@@ -228,15 +229,15 @@ minetest.register_node("pipeworks:valve_on_loaded", {
 	drop = "pipeworks:valve_off_empty",
 	mesecons = {effector = {
 		action_on = function (pos, node)
-			minetest.add_node(pos,{name="pipeworks:valve_on_empty", param2 = node.param2}) 
+			minetest.swap_node(pos,{name="pipeworks:valve_on_empty", param2 = node.param2})
 		end,
 		action_off = function (pos, node)
-			minetest.add_node(pos,{name="pipeworks:valve_off_empty", param2 = node.param2}) 
+			minetest.swap_node(pos,{name="pipeworks:valve_off_empty", param2 = node.param2})
 		end
 	}},
 	on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
 		local fdir = node.param2
-		minetest.add_node(pos, { name = "pipeworks:valve_off_empty", param2 = fdir })
+		minetest.swap_node(pos, { name = "pipeworks:valve_off_empty", param2 = fdir })
 	end,
 	on_rotate = pipeworks.fix_after_rotation
 })
diff --git a/init.lua b/init.lua
index 2e05337..470db2e 100644
--- a/init.lua
+++ b/init.lua
@@ -14,14 +14,18 @@ pipeworks.worldpath = minetest.get_worldpath()
 pipeworks.modpath = minetest.get_modpath("pipeworks")
 
 dofile(pipeworks.modpath.."/default_settings.lua")
-
 -- Read the external config file if it exists.
+
+
 local worldsettingspath = pipeworks.worldpath.."/pipeworks_settings.txt"
 local worldsettingsfile = io.open(worldsettingspath, "r")
 if worldsettingsfile then
 	worldsettingsfile:close()
 	dofile(worldsettingspath)
 end
+if pipeworks.enable_new_flow_logic then
+	minetest.log("warning", "pipeworks new_flow_logic is WIP and incomplete!")
+end
 
 -- Random variables
 
@@ -114,6 +118,12 @@ dofile(pipeworks.modpath.."/wielder.lua")
 if pipeworks.enable_pipes then dofile(pipeworks.modpath.."/pipes.lua") end
 if pipeworks.enable_teleport_tube then dofile(pipeworks.modpath.."/teleport_tube.lua") end
 if pipeworks.enable_pipe_devices then dofile(pipeworks.modpath.."/devices.lua") end
+-- individual enable flags also checked in register_flow_logic.lua
+if pipeworks.enable_new_flow_logic then
+	dofile(pipeworks.modpath.."/new_flow_logic.lua")
+	dofile(pipeworks.modpath.."/register_flow_logic.lua")
+end
+
 if pipeworks.enable_redefines then
 	dofile(pipeworks.modpath.."/compat-chests.lua")
 	dofile(pipeworks.modpath.."/compat-furnaces.lua")
diff --git a/new_flow_logic.lua b/new_flow_logic.lua
new file mode 100644
index 0000000..3fd1bb6
--- /dev/null
+++ b/new_flow_logic.lua
@@ -0,0 +1,121 @@
+-- reimplementation of new_flow_logic branch: processing functions
+-- written 2017 by thetaepsilon
+
+
+
+-- global values and thresholds for water behaviour
+-- TODO: add some way of setting this per-world
+local thresholds = {}
+-- limit on pump pressure - will not absorb more than can be taken
+thresholds.pump_pressure = 2
+
+
+
+-- borrowed from above: might be useable to replace the above coords tables
+local make_coords_offsets = function(pos, include_base)
+	local coords = {
+		{x=pos.x,y=pos.y-1,z=pos.z},
+		{x=pos.x,y=pos.y+1,z=pos.z},
+		{x=pos.x-1,y=pos.y,z=pos.z},
+		{x=pos.x+1,y=pos.y,z=pos.z},
+		{x=pos.x,y=pos.y,z=pos.z-1},
+		{x=pos.x,y=pos.y,z=pos.z+1},
+	}
+	if include_base then table.insert(coords, pos) end
+	return coords
+end
+
+
+
+-- local debuglog = function(msg) print("## "..msg) end
+
+
+
+-- new version of liquid check
+-- accepts a limit parameter to only delete water blocks that the receptacle can accept,
+-- and returns it so that the receptacle can update it's pressure values.
+-- this should ensure that water blocks aren't vanished from existance.
+-- will take care of zero or negative-valued limits.
+pipeworks.check_for_liquids_v2 = function(pos, limit)
+	if not limit then
+		limit = 6
+	end
+	local coords = make_coords_offsets(pos, false)
+	local total = 0
+	for index, tpos in ipairs(coords) do
+		if total >= limit then break end
+		local name = minetest.get_node(tpos).name
+		if name == "default:water_source" then
+			minetest.remove_node(tpos)
+			total = total + 1
+		end
+	end
+	return total
+end
+
+
+
+
+local label_pressure = "pipeworks.water_pressure"
+local label_haspressure = "pipeworks.is_pressure_node"
+pipeworks.balance_pressure = function(pos, node)
+	-- debuglog("balance_pressure() "..node.name.." at "..pos.x.." "..pos.y.." "..pos.z)
+	-- check the pressure of all nearby nodes, and average it out.
+	-- for the moment, only balance neighbour nodes if it already has a pressure value.
+	-- XXX: maybe this could be used to add fluid behaviour to other mod's nodes too?
+
+	-- unconditionally include self in nodes to average over
+	local meta = minetest.get_meta(pos)
+	local currentpressure = meta:get_float(label_pressure)
+	meta:set_int(label_haspressure, 1)
+	local connections = { meta }
+	local totalv = currentpressure
+	local totalc = 1
+
+	-- then handle neighbours, but if not a pressure node don't consider them at all
+	for _, npos in ipairs(make_coords_offsets(pos, false)) do
+		local neighbour = minetest.get_meta(npos)
+		local haspressure = (neighbour:get_int(label_haspressure) ~= 0)
+		if haspressure then
+			local n = neighbour:get_float(label_pressure)
+			table.insert(connections, neighbour)
+			totalv = totalv + n
+			totalc = totalc + 1
+		end
+	end
+
+	local average = totalv / totalc
+	for _, targetmeta in ipairs(connections) do
+		targetmeta:set_float(label_pressure, average)
+	end
+end
+
+
+
+pipeworks.run_pump_intake = function(pos, node)
+	-- try to absorb nearby water nodes, but only up to limit.
+	-- NB: check_for_liquids_v2 handles zero or negative from the following subtraction
+	local meta = minetest.get_meta(pos)
+	local currentpressure = meta:get_float(label_pressure)
+	local intake_limit = thresholds.pump_pressure - currentpressure
+	local actual_intake = pipeworks.check_for_liquids_v2(pos, intake_limit)
+	local newpressure = actual_intake + currentpressure
+	-- debuglog("oldpressure "..currentpressure.." intake_limit "..intake_limit.." actual_intake "..actual_intake.." newpressure "..newpressure)
+	meta:set_float(label_pressure, newpressure)
+end
+
+
+
+pipeworks.run_spigot_output = function(pos, node)
+	-- try to output a water source node if there's enough pressure and space below.
+	local meta = minetest.get_meta(pos)
+	local currentpressure = meta:get_float(label_pressure)
+	if currentpressure > 1 then
+		local below = {x=pos.x, y=pos.y-1, z=pos.z}
+		local name = minetest.get_node(below).name
+		if (name == "air") or (name == "default:water_flowing") then
+			minetest.set_node(below, {name="default:water_source"})
+			meta:set_float(label_pressure, currentpressure - 1)
+		end
+	end
+end
diff --git a/pipes.lua b/pipes.lua
index 9771e3b..54dfbd7 100644
--- a/pipes.lua
+++ b/pipes.lua
@@ -191,6 +191,16 @@ table.insert(pipes_full_nodenames,"pipeworks:valve_on_loaded")
 table.insert(pipes_full_nodenames,"pipeworks:entry_panel_loaded")
 table.insert(pipes_full_nodenames,"pipeworks:flow_sensor_loaded")
 
+pipeworks.pipes_full_nodenames = pipes_full_nodenames
+pipeworks.pipes_empty_nodenames = pipes_empty_nodenames
+
+
+
+
+if not pipeworks.enable_new_flow_logic then
+-- sorry, no indents... it messes with the patchlogs too much
+
+
 minetest.register_abm({
 	nodenames = pipes_empty_nodenames,
 	interval = 1,
@@ -227,3 +237,6 @@ minetest.register_abm({
 	end
 })
 
+
+
+end
diff --git a/register_flow_logic.lua b/register_flow_logic.lua
new file mode 100644
index 0000000..c9df09c
--- /dev/null
+++ b/register_flow_logic.lua
@@ -0,0 +1,58 @@
+-- register new flow logic ABMs
+-- written 2017 by thetaepsilon
+
+local pipes_full_nodenames = pipeworks.pipes_full_nodenames
+local pipes_empty_nodenames = pipeworks.pipes_empty_nodenames
+
+-- run pressure balancing ABM over all water-moving nodes
+-- FIXME: DRY principle, get this from elsewhere in the code
+local pump_on = "pipeworks:pump_on"
+local pump_off = "pipeworks:pump_off"
+local spigot_off = "pipeworks:spigot"
+local spigot_on = "pipeworks:spigot_pouring"
+
+local pipes_all_nodenames = pipes_full_nodenames
+for _, pipe in ipairs(pipes_empty_nodenames) do
+	table.insert(pipes_all_nodenames, pipe)
+end
+
+if pipeworks.enable_pipe_devices then
+	table.insert(pipes_all_nodenames, pump_off)
+	table.insert(pipes_all_nodenames, pump_on)
+	table.insert(pipes_all_nodenames, spigot_on)
+	table.insert(pipes_all_nodenames, spigot_off)
+end
+
+
+if pipeworks.enable_pipes then
+	minetest.register_abm({
+		nodenames = pipes_all_nodenames,
+		interval = 1,
+		chance = 1,
+		action = function(pos, node, active_object_count, active_object_count_wider)
+			pipeworks.balance_pressure(pos, node)
+		end
+	})
+end
+
+if pipeworks.enable_pipe_devices then
+	-- absorb water into pumps if it'll fit
+	minetest.register_abm({
+		nodenames = { pump_on },
+		interval = 1,
+		chance = 1,
+		action = function(pos, node, active_object_count, active_object_count_wider)
+			pipeworks.run_pump_intake(pos, node)
+		end
+	})
+	-- output water from spigots
+	-- add both "on/off" spigots so one can be used to indicate a certain level of fluid.
+	minetest.register_abm({
+		nodenames = { spigot_on, spigot_off },
+		interval = 1,
+		chance = 1,
+		action = function(pos, node, active_object_count, active_object_count_wider)
+			pipeworks.run_spigot_output(pos, node)
+		end
+	})
+end