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Boiler Water Loops - In boiler water loops there are different ways to arrange the piping depending on the budget at installation time and how efficient and balanced you want the hydronic piping system to be when the job is complete. Some piping arrangements require more pipe upon initial installation. However, they are easier to balance and provide even heat throughout all the radiators or baseboards.
Boiler Water Loops | Hydronic Piping Systems
It is important to consult with a plumbing and heating professional. Consultation should be done before deciding which type of hydronic piping arrangement you want. The type of boiler water loop you will use for your hydronic loop. They can show you the distinct advantages and disadvantages along with the cost differences of various hydronic piping arrangements.
The piping system you need for the structure where you intend on installing this system. The type of loop can oftentimes be just as important as properly sizing the boiler pipe and system as a whole. It can make all the difference in the world in comfort and efficiency. Consulting a professional will ensure the design is done properly from the start.
One Pipe Series Loop
The One Pipe Series Hydronic Loop uses less pipe than any other hydronic piping arrangement. Therefore it is less expensive to install the piping. However, you need bigger radiators or longer baseboards. However, only at the end of the loop because this part of the boiler water loop will have less heat. The radiators or baseboards at the beginning of the loop use most of the heat.
Consequently, this is the reason for the larger radiators and baseboards at the end of the loop. There is also a larger temperature drop in this type of boiler water loop. A temperature drop between the supply and the return versus other types of hydronic piping arrangements. The near boiler piping may need to be modified to prevent a large delta T between supply and return.
Monoflow Hydronic Loop and Monoflow Tees
The monoflow hydronic loop is similar to the one pipe series. The exception is the main loop uses monoflow tees to divert the water. It diverts the water to the radiators or baseboards using special Tees. The main hydronic loop maintains a constant flow on a call for heat. Using this system, the water temperatures for each zone are more even throughout the hydronic loop. More even than the one pipe series hydronic loop. The monoflow tee is a special tee. The monoflow tee is installed at the supply and the return. The supply and return for each radiator or baseboard.
This boiler water loop system is easy to zone but needs more piping and special monoflow tees for each separate circuit. Additionally, if not installed properly flow problems will occur in radiators and/or baseboards. It is really important if you have a monoflow system to consult a professional before making changes. If you want to modify it in any way for addition or other work. Always consult a plumbing and heating HVAC specialist for any changes to a monoflow loop.
Two Pipe Direct Return Hydronic Loop
The Two Pipe Direct Return Boiler Water Loop utilizes more pipe than the one pipe series loop. However, all radiators and baseboards receive the same temperature of the water, therefore it is more even heat. More even heat than in all the radiators and/or baseboards than the one pipe series loop. Another advantage of a two-pipe direct return loop over the one pipe series loop is that it can be zoned.
Zoning gives you more control over where and when you want to heat. This can save you money on the cost of heating. As with many hydronic loop systems the two-pipe direct return needs balancing valves. The near boiler piping may need to be modified to prevent a large delta T between supply and return.
Two Pipe Reverse Return Hydronic Loop
The Two-Pipe Reverse Return Boiler Water Loop uses more pipe than the two-pipe direct return hydronic loop. However, the flow is more balanced and even than the two-pipe direct return boiler water loop. All baseboards and radiators receive the same temperature of the water so are the same as the two-pipe direct return. However, it is an advantage over the one pipe series hydronic loop.
Zoning is also possible with a two-pipe reverse return boiler water loop. Zoning will offer you savings on your heating bill. It does this by taking advantage of hydronic loop zoning and large pressure drop.
Conclusion | Boiler Water Loops
It should be noted that any piping system will be more efficient if the piping is insulated especially boiler piping.
Boiler Water Loops
I have a single zone system that has one loop for the upstairs and another for the 1st floor with a common supply and return manifolds. The only pump in the system is the Taco .005 that is in the boiler. I do not have any zone valves. I control the temp in the rooms by opening/closing the louvers on the baseboard. It heats the house fine and the return temp on the water is about 145 and the supply is 180. This has been working for 30 years. I’m about to replace the old boiler (It’s a 91% AFUE floor model w/cast iron exch) and my quotes all want to go to a wall mounted unit. will these units work without extra circulating pumps ? Thank you.
Depending on the design of the system you will need a pump or the boiler won’t fire. Flow of water must be established first before they will fire. And I’ve seen these used successfully as heating and domestic hot water use. They take up much less space than the conventional boilers. See our boiler reviews pages. We have a few reviews for wall mounted boilers there.
Is there a more efficient heat transfer medium other than water that may be less corrosive? I have a 100 year old home with a lot of original iron pipe servicing a low pressure residential boiler. Thanks for the forum. /jg
When you say low pressure boiler I have to assume it is a steam boiler? As far as I know water is it for boilers whether it is hot water or steam. And I don’t think the issue is corrosion much as it is a mineral problem. With steam boilers it is super important to flush it or blow it down weekly and with hot water boilers it is important to flush the system from time to time. There are also solutions you can buy to add to the water to reduce this problem as much as possible. Water by itself is not corrosive especially to iron pipes. It is the minerals and such in the water that causes the problems.
my plumber put mono flow tee on the 2 pipe return system 🙂
what should i tell him about life ?
Life is really simple, but we insist on making it complicated – Confucius
It might work depending on the direction of the flow and how he installed it. When in a pinch I guess it will work……………again depending on how the flow is and how he installed it.
I have a 3 zone mono flow loop system and I don’t seem to get enough heat unless I crank thermostats up to 78 on the first two floors ?
First of all you need to answer a few questions?? Has anything in the loop changed? A new circulator pump? A valve on the main loop been closed or shut down to restrict flow? Is the pump turning the proper RPM’s? The reason I say this is because flow for a mono-flow system is very important. Next I’d check for air. Do you have air bleeders on the radiators? If so make sure to open them until you get water. It’s important no air is in the loop. Air tends to migrate and get stuck in any riser part of the system including radiators. There are automatic air vents but you likely have the air vents that require a special key to open them manually. Once the air is bled from the radiators full flow should be restored causing proper heating. Additionally, it doesn’t hurt to flush the system with fresh water from time to time. Call you local HVAC or plumbing contractor to help you with that.
I have a one pipe system with a monoflo tee on the return. Can I it a pump on there to get more flow?
not recommended……………..a pro needs to look at this to help…………….more flow or increased velocity is not always best and could result in more problems and less efficiency.
The last fin tube in the loop is not getting water. The line has been rodded but, but the water is intermittent. What changed and what can I do? The flow control valve was opened more also.
It is likely still clogged. You likely have hard water and thus hard water problems with lots of minerals in the water. It is a good idea to flush the system annually if you have hard water. A good annual flush of the system will prevent future problems like this.