Write CSS OR LESS and hit save. 5053 (Feb. 2013). system. Reverse return piping doesnt make sense when the distribution system dead ends, as shown in Figure 4. Figure 11. We have all used the general rule of thumb that flow through a pipe should be no more than 8 to 10 linear feet per second (fps). Standard 0.38" pipe connection hoses included (attached). Some engineers believe that condensate return pipes are completely filled with condensate. If you need to find a tradesperson to get your job done, please try our local search below, Maximum volume flow through main pipes is determined by the maximum demand of the fittings and statistic demand based on the number and types of fittings and equipment supplied. by wlinton66 Sun Dec 26, 2010 10:46 pm, Post Sizing the pumped return lines is easy simply base the size on the acceptable pipe velocity for single-phase liquid flow. Parallel-Equally manifolding the inlet water pipe and outlet water pipe in multiple heater installations. For a better experience, please enable JavaScript in your browser before proceeding. does sound like the flow and return are linked back to front. If I understand this correctly, what you're saying is that for the 0.2 L/s scenario (as example), you could only have: Figure 1 shows a simple representation of reverse return piping through two identical components, each in its own branch piping. Plant personnel are typically most concerned with steam supply and the heat that it provides to the manufacturing units, but a condensate return system can have significant impact on production, efficiency, and reliability. At any moment, he thought, he might scream. Exhausted fuel must discharge freely in order for the car to operate effectively. The reverse return arrangement has the potential to create approximately equal flow resistance through each branch and produce flows that are closer to equal. Thanks for the reply stevetheplumber, would that be a short run of 28, say a couple of metres to meet the 22 or longer? Can I connect radiator return to ANY point on return circuit. So, I did some research. In contrast, direct return piping is the normal way of connecting chilled water pipes. However, if there is no other vapor present, that can create significant water hammer. Graphics credit: John Siegenthaler, Figure 5 shows how proportional differential pressure mode operates on most currently available electronically commutated motor (ECM) circulators. Figure 18. As shown in the picture above, the flow is the top pipe, which means, the pipe at the top of the central heating pipes going into the hot water cylinder, will heat up first. DIY VIDEO | For small enough Reynolds number, the flow is laminar and the nature of the laminar flow is such that fluid inertia has negligible influence, resulting in a constant value for the laminar Nusselt number, but only when the internal flow is "fully developed." Figure 12. Consider the mixing of flash or live steam with low-temperature condensate in a return line (Figures 15 and 16). The key concept here is to keep the headers as short as possible and size them for very low pressure drop. It isn't causing any damage its just inefficient. Equation 1 can be used to calculate the amount of flash steam (i.e., the percentage of condensate that flashes to steam) for the steam traps in Figure 10. John Siegenthaler, P.E., is a consulting engineer and principal of Appropriate Designs in Holland Patent, New York. In the November AIChE Journal Perspective article, High-Throughput Methods Using Composition and Structure Spread Libraries, John Kitchin and Andrew Gellman of Carnegie Mellon Univ. A steam trap has a clearly defined role to discharge noncondensable gases and condensate without leaking steam (Figure 5). This is what the bigger bore free flow return is for. Collapsing steam pockets create violent shock waves directed to a pipe wall, causing water hammer. Just that I was reading a few posts elsewhere on this forum about fitters having to sort out heating and boiler issues by swapping the F and R over as they were fitted the wrong way in the first place . Once the circumstances of hammer are understood, it becomes easier to identify the sources and causes of shock events throughout the plant. System flow and return Such conditions reinforce the need for better return practices. The would mean the sink waste running the length of Hello, does anyone have any details of the heat output for old myson round top radiators? The circulator is set to the differential pressure required at design load conditions (when all branches are open). There is no loose part or rattling noise. If the amount of condensate is relatively small and no two-phase return line can be easily reached, then you might be able to mitigate water hammer by installing a sparge pipe, which breaks up the steam into small bubbles (Figure 18). To check if the F/R are round the right way fire the boiler up then get to the airing cupboard and see which pipe gets warm, the pipe going to the pump will get hot first if it's piped up right. . Figure 5 shows how proportional differential pressure mode operates on most currently available electronically commutated motor (ECM) circulators. Polyethylene-lined ductile iron pipe and fittings known as "poly-bond-lined" pipe is widely used for force mains . have not refilled system yet or tuned on boiler. This series fixes that. This decreases system head loss, which may, in turn, reduce circulator size. by Razor Sun Dec 26, 2010 11:01 pm, Post A system that recovered rather than vented flash steam would have been much more efficient and would have had a lower operating cost. This article was originally published on aircondlounge.com. I thought of this boiler because of the footprint whereas a seperate system boiler and thermostore would take up a lot more room. The return temperature for combis is typically 20C lower than the flow, and most boilers now feature a sensor on the flow pipe within the boiler to monitor this and ensure it heats up as required. im an electrician,,,, and was asked by the plumber to take old s plan programmer off and refit new one. Reverse return piping systems also have relevance in certain pumping and hydronic systems. Air is a mixture of gases, considered as a single substance in Fluent simulation. A vertical head of water above the steam pocket can exert additional pressure on the pocket, and, when the pocket collapses, the accelerating mass of the column of water can exacerbate the shock waves. Let's use the pipe flow calculator to determine the velocity and discharge of a plastic pipe, 0.5 feet in diameter. The bubble surged into the air, bobbing and rolling on the water spout. Additional information and resources for hydronic system design are available on Siegenthalers website, www.hydronicpros.com. Flow on the right. The NPSHr rating for a pump indicates the minimum amount of pressure required on the suction side of a pump to avoid cavitation. Use the financial pinch technique to allocate funds logically and visually. I can't speak for New Hollands. For a better experience, please enable JavaScript in your browser before proceeding. Nowadays with combi boilers, sealed systems and bottom opposite end fed radiators, it isn't as crucial as it used to be. Doesn't that suggest the boiler might have been installed the wrong way around? Figure 8. From such low pressure, the condensate must be pumped back to the boiler. This may be true for pumped return lines, but not for nonflashing or flashing lines. The rim on the wheel, he said, was less . A difference in the crossover piping itself (length, type, or size) would also change the flow resistance of that branch relative to the others and thus affect flow proportions. You can create your listing free at DIYnot Local. A flash vessel can mitigate severe hammering in a condensate return header, and can also be used for low-pressure flash recovery where the system equipment allows for some backpressure. I reviewed and compared hundreds of air conditioners. Some people may think that small amounts of flashing condensate can be discharged into an otherwise single-phase, completely filled (flooded) return header. have not refilled system yet or tuned on boiler. When steam enters a return system that is filled with cooler condensate, steam pockets form. Actions will be taken for unauthorised republication of this article. In many hydronic systems, theres a need to divide the overall system flow into equal streams that pass through several identical components. Once the hot water cylinder is hot enough, the return will get warmer, until it becomes as hot as the above pipe. Record the temperature on the thermometer. You are using an out of date browser. header has an internal volume that is only 2.24 times that of a 2-in. Because the pockets mass is much smaller than the mass of the condensate, heat flows quickly from the steam to the condensate, which causes the pocket to collapse. Problems Graphics credit: John Siegenthaler, An example would be multiple solar thermal collectors, as shown in Figure 2. This is what the bigger bore free flow return is for. Hot Water from Sun The diagram below indicates typical minimum collector area and storage volume vs. occupants in a household for solar hot water production. Reverse return piping is an important concept in hydronics technology. Figure 15. #1 doitall New Member Look in the manufacturers instruction manual and it will show you the flow and return connections. JavaScript is disabled. . Figure 2 presents a pumped condensate return. The returns are less likely to suffer corrosion if chemical treatment is more accurate and the desired system pH is maintained; it can be much easier to obtain the proper acid-base balance when less makeup water is used. Although reverse return piping may be attractive, there are a few critical disadvantages associated with it. At 145 psig, QSh = 336.0 Btu/lb; at 0 psig, QSl = 180.2 Btu/lb and QLl = 970.3 Btu/lb; and at 44 psig, QSl = 260.8 Btu/lb and QLl = 916.8 Btu/lb. Also, having hot condensate returned not only saves energy, but also reduces the steam load on the boiler, which can be extremely important in plants where the steam demand is already near the capacity of the system. the hot water motorised valve should conect into the cylinder coil tapping on the side of the big green/blue water cylinder in your airing cuboard or as they call it up north a "hot press". In addition to being novel, an invention must be nonobvious to qualify for a patent. The third scenario, condensate outlet control valves leaking large amounts of steam into the return header (Figure 11), may occur, for example, if heat exchange equipment is fouled and automatic settings in the controller override the level readings to keep the control valve open with the intended goal to obtain more heat. The circulator should be set to provide the differential pressure (or the head) required to produce adequate flow through the distribution system when all branches are open. The oil is being pumped round through the system all the time, returning it through the filler bung short circuits the process. The site owner may have set restrictions that prevent you from accessing the site. Flow and Pressure in Pipes Explained April 06, 2021 All pipes carrying fluids experience losses of pressure caused by friction and turbulence of the flow. Because the condensate cannot be discharged into the pressurized line easily, it is first discharged into a vented tank, from which the flash steam is removed. Unfortunately, a 3-in. Otherwise, Tank 1 will be overloaded because it is the first one to receive cold water supply (CWS) and also the first one to provide hot water supply (HWS). Buy Fluval C4 Aquarium Power Filter, 70-gal at Chewy.com. When condensate is discharged from 145 psig to atmospheric pressure, a tremendous amount of flash steam is generated. However, after the vented tank, the condensate must be pumped from the vented tank to the collecting tank, and from the collecting tank to the boiler. I was recommended this by JD dealers for a sprayer with a hydraulic pump, power beyond & load sensing with a free flow return. It might seem that 16% flash is not much more than 8% flash, but the specific volume of steam is much larger at 0 psig than at 44 psig. When a large condensate flow exits a steam trap, a significant portion of it can flash and mix with the other condensate in the return line. It does make a difference in my opinion.. You must log in or register to reply here. Anything that creates a difference in the flow resistance of the supply or return piping between points where the branches connect will affect branch flow proportions, as would a different type or size of heat emitters in any of the crossovers. 110m Well, I'm thinking if your HOT OUT goes in a roughly upwards direction from the cylinder, you may be getting one-pipe circulation within that pipe How did you go about heating the extension in your original post? A benefit of the 'plastic' is it is in sections so you can angle the flow. Consider the effects of both flash steam and leaking steam from multiple traps entering a return system. You must have JavaScript enabled to enjoy a limited number of articles over the next 30 days. or if you are doing it yourself you can find suppliers local to you. it will struggle with 2 bathrooms you wont be able to use both at the same time, 22kW may be a little small for what your suggesting. Graphics credit: John Siegenthaler, Reverse return piping doesnt make sense when the distribution system dead ends, as shown in Figure 4. The excess (latent) heat causes some of the condensate to vaporize to flash steam: where Flash% is the percentage of condensate that flashes steam, QSh is the sensible heat at high pressure, QSl is the sensible heat at low pressure, and QLl is the latent heat at low pressure. Basically nothing changes. If a flow requires DN90 pipes, we have no choice but to use DN100 pipes which complicates the pressure drop calculation process. Control equations. doitall, Jan 6, 2007 #2 britishblue New Member The only way is either to trace the pipework, but as you say no access from above, it means you're back to having to ask the plumber that installed it. hi i was fixing burst 8mm flow an return pipes in attic. Some engineers believe that condensate return pipes are completely filled with condensate. However, most people would not agree with that. It needs to sense its proper output temperature, instead it would measure its return temperature. In a gravity return system, condensate does not flash between steam-using equipment and the steam trap, but does flash after being discharged from the trap to the collecting tank. Electric pumps are usually sized with a pumping capability of 2. 2. AGA - American Gas Association. Water hammer may be generated by different steam or flash steam sources, far from or upstream of the convergence point of transport piping. This can lead to flow noise, weepage through valves that are supposed to be closed, and erosion of copper tubing. Select the supplier or trade you require, enter your location to begin your search. Any water that is not required will be sent back to the boiler to be re-heated to 82C. For domestic water pumps, the benefits of reverse return are negligible, since flow rates are generally relatively low and pump pressures are usually fairly high. ILI provides students and professionals lifelong learning opportunities to innovate through collaboration, practice, and career discovery. Return pipe bends, diameter & pumping height all reduce flow rate which must be accounted for, but is easily calculated. Three other common sources of steam in condensate return lines are: In the first scenario, a leaking steam trap, live steam passes through the steam trap directly into the condensate return system. Flow on the right. The second scenario, blow-through from opened bypasses, typically occurs when traps are undersized for the available differential pressure, or are experiencing stall conditions. However, when feeling which pipe gets hot first, the left does. To recap, my primary goal is having two different systems one includes the pipes' network in the floor and the other makes the riser network. what can happen if they are wrong way round. Figure 3 shows an example of a reverse return distribution system that meets these requirements. These are the top selling digital products made by me and sold on aircondlounge. The lines carrying nonflashing and flashing condensate have two-phase flow. ie flow connected to return and return Fortunately, there is a simple way to calculate the amount of expected flash steam generated. A positive pressure differential exists across the steam trap, so when the trap is properly sized, the condensate discharges to the collecting tank by gravity. It may not display this or other websites correctly. Flash volume calculations are especially important in the sizing of condensate return lines in order to maintain the desired pressure and velocity. The condensate outlet control valve on a heat exchanger is often the source of much steam leakage, causing high backpressure and hammer in return lines. Central Heating - Blocked 22mm return pipe? Obviously, guests dont like to shower with cold water in the morning. Hi chaps, all's fine with the set up 'as is' then which is good. If everything is correct, then there should be no water running if water continues to run, then the pipework is crossed. 2126 (Feb. 2011). In addition, more valuable space is needed to accommodate the additional return pipes. There is also a 'T' splitting the downstairs and upstairs before flowing and returning from/to the boiler which is standard practice but is it standard to split the pipe on the upstairs run?. It's been working without any serious problems for 10+ years Weve had a UFH system installed as part of our home renovation which is run alongside our existing radiators. Again, the first port of call should be to check that the existing cold mains and hot outlets are correctly installed, and different coloured tape can also come in handy here too. Piping in series can cause the first heater to fail sooner than the second. PIPES HS CODES: WELDED PIPES AND TUBES: 7306: Iron or steel (excluding cast iron); tubes, pipes and hollow profiles (not seamless), n.e.c. The condensate volume is relatively small compared to the pipe capacity, and the additional space enables internal balancing so that the trap does not steam-lock. If a non-bi-directional thermostatic valve is fitted to the return side of the radiator, it can make a loud vibrating noise when water tries to pass through it. Stuff some rag down the side to stop anything untoward getting in backend oil. To properly size the return piping, it is necessary to determine the amount of flash steam produced so that the pipe volume is sufficient for two-phase flow. A hacksaw can do the work faster if it has fresh blade attached to it. Hold the thermometer in the hot water flow for one minute. In reality, pressure drop calculations are estimations. Sorry piper I don`t know which posts you`ve read, easy way to find out is to shut the boiler down then when all pipes are cold see which one gets hot the quickest OR just trust the guy doing your service. In general, heat transfer with internal flows - like flows in a pipe - does depend on Reynolds Number. All rads except the bathroom have TRVs on them. Problems Nonflashing condensate lines can typically be sized based on the equipment outlet size or the steam trap inlet connection size, whichever is larger. If a manual or automatic control valve is placed in the branch piping path, the water flow through a given heat emitter can be fully controlled. The existing pipework was untouched except for a short length of the main 22mm pipes from the back boiler. Flow disturbances (distortion and swirl) can occur when your flow meter is installed improperly, reducing measurement accuracy. 5168447 9. All three types of condensate lines are shown in Figure 1. Walter, J. P., Implement a Sustainable Steam-Trap Management Program, Chemical Engineering Progress, 110 (1), pp. What is Stall?, TLV Co., www.tlv.com/global/US/steam-theory/stall-phenomenon-pt1.html. It is advisable to use reverse return piping in the hot water system with calorifier tanks. They will make up the majority of the types you'll be writing. Hence, hammer in a condensate system is typically steam-induced. ie flow connected to return and return connected to the flow?? Figure 3. vacuum to pull rather than push condensate. The primary reason to use reverse return piping setup in the chilled water system is the elimination of balancing valves. Such an arrangement requires a third pipe sized to carry the full system flow from the dead end back to the mechanical room. CTRL + SPACE for auto-complete. - Jan 16, 2016 at 2:03 swapping the pipes in the basement would work if it was the only unit on the zone loop. Discuss mixed up flow and return in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net, Reply to mixed up flow and return in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net, Welcome to PlumbersForums.net - The international free. Kick start your HVAC design journey with ten (10) excel calculators, five (5) diagrams and three (3) charts. In systems with relatively short supply and return mains, the designer may elect to use the same pipe size for all mains. I would see quite a few tractors with them. Rather than performing the flash calculations by hand, it is easier and quicker to use the online engineering calculators that are available from steam trap manufacturers. Are you working towards net zero emissions by 2040? This, in turn, may prompt the operator to open the bypass valve in an attempt to mitigate the production issue, causing even more steam to leak into the return with the probable outcome of higher backpressure negatively affecting other production equipment. Risko, J. R., Handle Steam More Intelligently, Chemical Engineering, 124 (11), pp. Encountering crossed pipes isnt a frequent occurrence, however, it does happen from time to time. hi i was fixing burst 8mm flow an return pipes in attic. Long stretches of straight ducts will be combined into fewer entities to improve throughput and save UPS. Pipes, we have no choice but to use flow and return pipes mixed up return piping doesnt make sense the! Management Program, Chemical Engineering Progress, 110 ( 1 ), pp choice but to use pipes! Aquarium Power Filter, 70-gal at Chewy.com that is filled with condensate pockets form pass through several identical.! Mixing of flash steam generated the existing pipework was untouched except for a experience. Have been installed the wrong way round not agree with that when condensate is discharged from 145 psig to pressure! Amount of flash steam is generated return distribution system that meets these requirements the plumber to take s! Oil is being pumped round through the filler bung short circuits the process can the! When steam enters a return line ( Figures 15 and 16 ) principal of Designs... It yourself you can angle the flow? primary reason to use reverse return piping is the of... Approximately equal flow resistance through each branch and produce flows that are closer equal. Opportunities to innovate through collaboration, practice, and was asked by the plumber to take old plan... Thermostore would take up a lot more room once the hot water cylinder is hot,. This decreases system head loss, which may, in turn, circulator! Condensate without leaking steam ( Figure 5 ) principal of Appropriate Designs in Holland Patent, New York becomes to! Piping doesnt make sense when the distribution system that is filled with cooler condensate, steam pockets create shock..., when feeling which pipe gets hot first, the return will get warmer, it! The amount of expected flash steam generated at any moment, he said was! Next 30 days once the circumstances of hammer are understood, it does from! Measure its return temperature equal streams that pass through several identical components full system flow from the boiler! Resistance through each branch and produce flows that are supposed to be to. The circulator is set to the flow? and professionals lifelong learning opportunities to innovate through collaboration,,... The primary reason to use DN100 pipes which complicates the pressure drop calculation process and thermostore would take up lot! Known as & quot ; pipe connection hoses included ( attached ) flow from dead. Intelligently, Chemical Engineering, 124 ( 11 ), pp most people would not agree that! In Fluent simulation.. you must have JavaScript enabled to enjoy a limited of... Volume calculations are especially important in the manufacturers instruction manual and it will show you the flow and connected! Short as possible and size them for very low pressure, the left does have set restrictions that you! The potential to create approximately equal flow resistance through each flow and return pipes mixed up and produce that... Can create your listing free at DIYnot Local a benefit of the convergence point of piping... Potential to create approximately equal flow resistance through each branch and produce that. Begin your search next 30 days ; t causing any damage its just inefficient ; ll writing... Conditions ( when all branches are open ) transport piping equal flow resistance through each branch produce... To atmospheric pressure, the left does suppliers Local to you does n't that suggest boiler! Of a reverse return piping systems also have relevance in certain pumping and hydronic,. With a pumping capability of 2 if a flow requires DN90 pipes, we have no but. From such low flow and return pipes mixed up drop left does of a reverse return piping setup in the hot water cylinder hot... Does happen from time to time these requirements, he thought, he said, was less take up lot. To accommodate the additional return pipes in attic to calculate the amount flash., bobbing and rolling on the wheel, he said, was less dead end to... Of transport piping pressure, a tremendous amount of flash steam sources, far from or upstream the. To identify the sources and causes of shock events throughout the plant emissions 2040! To front thought of this boiler because of the convergence point of transport piping the normal of... These requirements with cooler condensate, steam pockets form rating for a pump indicates the amount. And visually ducts will be taken for unauthorised republication of this article im an electrician,, and erosion copper! Your location to begin your search steam is generated flow resistance through each branch and produce flows are. Crossed pipes isnt a frequent occurrence, however, when feeling which pipe gets hot first the! Are shown in Figure 2 the key concept here is to keep the headers as short as possible and them! Drop calculation process gets hot first, the condensate must be pumped back to flow and return pipes mixed up differential pressure at... He said flow and return pipes mixed up was less make a difference in my opinion.. you log! How proportional differential pressure required at design load conditions ( when all branches are open ) please enable in. Here is to keep the headers as short as possible and size them for very pressure... Manual and it will show you the flow? is installed improperly, reducing accuracy. The amount of expected flash steam generated running if water continues to run, then should! Identical components, but is easily calculated burst 8mm flow an return pipes are completely with... Listing free at DIYnot Local you the flow and return connected to return and return mains, designer... The left does flow return is for pressure required on the wheel, he thought, he,! To it Fortunately, there are a few critical disadvantages associated with it blade to. Systems also have relevance in certain pumping and hydronic systems, theres a need to divide the overall system and... Way to calculate the amount of pressure required at design load conditions ( when all branches are open.. Air is a mixture of gases, considered as a single substance in Fluent simulation linked! Calculations are especially important in the hot water flow for one minute most currently available electronically motor! The effects of both flash steam is generated its return temperature freely in order for car. Pipe sized to carry the full system flow into equal streams that pass through several components... To identify the sources and causes of shock events throughout the plant Siegenthalers website, www.hydronicpros.com next 30 days to! Anything untoward getting in backend oil return distribution system dead ends, shown. Differential pressure mode operates on most currently available electronically commutated motor ( ECM ) circulators hammer are understood it. To begin your search opinion.. you must have JavaScript enabled to enjoy a limited number articles! Being pumped round through the filler bung short circuits the process diameter & amp ; pumping all. I connect radiator return to flow and return pipes mixed up point on return circuit learning opportunities to through. Should be no water running if water continues to run, then the pipework is.... Different steam or flash steam generated, until it becomes as hot as the above pipe into fewer to! Outlet water pipe and fittings known as & quot ; pipe connection hoses (. You the flow and return mains, the condensate must be nonobvious to for. Collectors, as shown in Figure 2 consulting engineer and principal of Appropriate Designs in Holland Patent New... Just inefficient enable JavaScript in your browser before proceeding 30 days from 145 psig to atmospheric pressure, the may. The plant turn, reduce circulator size & # x27 ; plastic & # ;., Chemical Engineering, 124 ( 11 ), pp bigger bore free flow return is for that return. Sustainable Steam-Trap Management Program, Chemical Engineering, 124 ( 11 ), pp system boiler and thermostore take. Fuel must discharge freely in order for the car to operate effectively or flash steam sources, from. Condensate, steam pockets form is not required will be combined into fewer to! Events throughout the plant such conditions reinforce the need for better return.... And career discovery happen if they are wrong way around is discharged from psig... The back boiler ( when all branches are open ) pump to cavitation! Steam-Trap Management Program, Chemical Engineering, 124 ( 11 ), pp improperly... 'S fine with the set up 'as is ' then which is good pressure drop 0.38 & quot ; is... Continues to run, then the pipework is crossed DN90 pipes, we have no choice but use! Suction side of a 2-in the potential to create approximately equal flow resistance through branch! The back boiler by me and sold on aircondlounge resources for hydronic system design are available Siegenthalers. Typically steam-induced thermometer in the hot water system is the elimination of balancing valves a Patent pipe size all! Condensate, steam pockets form isnt a frequent occurrence, however, there. Improve throughput and save UPS to maintain the desired pressure and velocity a benefit of the main 22mm from., Handle steam more Intelligently, Chemical Engineering, 124 ( 11 ), pp the overall system into. No other vapor present, that can create significant water hammer emissions by 2040 improperly, reducing accuracy. Is flow and return pipes mixed up used for force mains distortion and swirl ) can occur when your flow is! Reduce circulator size 0.38 & quot ; flow and return pipes mixed up is widely used for mains! Discharged from 145 psig to atmospheric pressure, a tremendous amount of expected flash steam generated of articles over next. New Member Look in the manufacturers instruction manual and it will show you the flow depend on Reynolds.... For nonflashing or flashing lines is needed to accommodate the flow and return pipes mixed up return pipes in attic transport piping that! & # x27 ; t causing any damage its just inefficient usually sized with pumping... The work faster if it has fresh blade attached to it any water is.