Outdoor Reset Debate!

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  #1  
Old 03-03-18, 05:15 PM
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Angry Outdoor Reset Opinions

Hi all well let me start by stating I did have a Tekmar 256 on my boiler which I purchased and installed.

Well all I can say is for a single stage gas boiler they are of no use in my opinion. All I did was waste $150. To me the thermostat is what dictates comfort. Unless I planted my butt next to my baseboard, convector, radiator...I'm not going to tell if the heat coming out is 10 or 15 or 20 less on any particular day, weather dependent. I see zero savings with these devices. So what if my temperature runs at 160 degrees instead of 180. Again it's the thermostat that needs to be satisfied. If it's satisfied in 3 minutes at 180 degrees versus 10 minutes at 160 degrees, I see no fuel savings.

So honestly I'd like to hear from people on their opinions. I have since ripped mine out. It serve no value add. A thermostat set back a few degrees at night saves me more than the Tekmar gimmick junk
 

Last edited by 2014gt; 03-03-18 at 07:52 PM. Reason: Change Title
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  #2  
Old 03-03-18, 05:28 PM
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Thread moved from flooring to boiler forum.

Welcome to the forums.

We don't usually have debates in the help forums. Maybe some of the pros will offer their opinions.
 
  #3  
Old 03-03-18, 06:07 PM
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Outdoor reset is NOT a "gimmick", it really does work to save fuel. However, it DOES work better on some systems than others and YOUR system may be one where its value is limited.

Generally speaking, the more water contained in the entire system the better an outdoor reset will perform. If you have a small system with a minimal amount of water outdoor reset is of lower value.

If your system runs for only three minutes to satisfy the room thermostat you MAY have wider temperature swings than if the system ran for a longer period at a lower temperature. If you are satisfied with the comfort level then no reason to look farther.
 
  #4  
Old 03-03-18, 06:08 PM
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This could become quite lengthy and as PJ said, not for this forum but I will say that years ago I installed one in my house and came to the same conclusion as you and no longer have it.

That being said I do believe they have their purpose in commercial buildings where you don't always need the maximum heat output and the boilers are large enough to actually save you some money by shorter run times.

In my opinion as far as residential goes there are too many factors in older homes for these to be effective and have the same comfort level.

In theory you don't need as much heat at 50 deg. as you do at 0 deg to heat your house but that is not taking in leaky windows and doors and not as much insulation as you might like.

130 deg. water at 50 deg outside sounds good but factor in those other things and 130 might not do it if your doors and windows are letting in more cold air than the 130 deg water can overcome, possibly under radiated in some rooms, too many variables.

They have their purpose but are not for everybody.

To keep this short in my opinion, for residential, they are not worth the money.

Just my thoughts.
 

Last edited by spott; 03-03-18 at 06:23 PM.
  #5  
Old 03-03-18, 06:35 PM
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My experience is that not only does it save fuel even residentially but really improves the comfort levels in the home. The biggest problem with ODR to work well you need to have it set up properly. You need a heat loss done and determine the water temperatures required in the heating system. Will you have lower water temps In the system.absolutely. If we don't do the homework we will see less fuel savings and less comfort. A properly setup will also allow you to run a degree or two less temp on the thermostat..
 
  #6  
Old 03-03-18, 08:26 PM
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I would agree that in commercial I can see the usage.

I should clarify on a single some system, there in no benefit.

I don't see what the heat loss has to do with the water temperatures. In a hot water system they are designed around 180. Not sure you could go up to 190 and maybe you might squeeze a little more out of your heat emitters, or you can go down to 170, but all that does is take the thermostat longer to reach its setting. As far as comfort goes again unless you planted yourself on top of your heat emitter your're not going to feel a 5-10 difference...now if I put a thermocouple on it or a temp gun, sure those will electronically show and prove reduction in temperature. But, all that does is make the thermostat reach it's setting slower. You will not save any fuel/money by doing that.

If the ODR wants the water to be 160 degrees and runs for 15 min to hit the thermostat setting or without ODR the system runs at 180 degrees for 7 min...what did it accomplish? Not if I had some mega heat emitter in the house, or maybe a better description is a fireplace in a single room with its own thermostat (put aside most heat goes up the chimney) and the think was blazing a fire I couldn't sit right up near it and be comfortable , but the thermostat would hit temp quick. Save scenario, but I can dial back the fire lowwww. I can sit right in font of it and be fine...room would take a lot longer for stat to reach setting.

I'd like to hear more for all on this subject.
 
  #7  
Old 03-04-18, 07:05 AM
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In the days of coal, the fire burned all day. It could be somewhat adjusted according to the outside temp, and or heat load. So the rads were always warm, usually about half warm, or hot. They always were fully hot in the early am until the house came op to the temp "target".
The radiators [steam] radiators actually radiated, you could actually feel the heat quite a few feet away from them. I guess that the floor heating sort of mimics that."low temp all day" concept.
Sid
 
  #8  
Old 03-05-18, 04:40 AM
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An outdoor reset should only be used on heating systems that use multiple boilers or modulating boilers to provide the buildings heating needs. These systems will normally run 24/7 to provide a set temperature when the building is occupied and with a reduced temperature when unoccupied. For a residence a set back thermostat will suffice for most instances, so you can reduce the temperature during selected periods, (at work or at night). On large systems that I worked on a steady boiler run was much better than an on/off boiler cycle. In your situation, the reduced water temperature, will increase the boilers efficiency slightly and may save a few pennies Most of the time the payback on your investment for a reset device except for a thermostat is too far into the future to be cost effective However people that sell these devices will disagree.
 
  #9  
Old 03-05-18, 08:16 AM
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I think an ODR on a single zone, or simple residential system is probably not going to save the money it cost. However I was able to use the options of an ODR module on my Burnham ES-2 boiler to solve a unique problem and to see some slight savings in gas consumption. In my case it is a lifestyle choice.

I have 3 zones plus indirect hot water. The main house is 2 floors with cast iron radiators on one zone. Another zone is a master bedroom suite in a converted attic space with fin-tube baseboard. The third zone is an all-glass greenhouse room with fin-tube radiant attached to the main house with sliding doors. The indirect HW is also a zone. The boiler is oversized: about twice the size of the calculated (and confirmed by measurement) load.

I use the ODR to run all except the greenhouse on a DHW setting of 150 degrees and run the greenhouse on an ODR curve that increases the boiler temp incrementally from 150 to 180 as outdoor temp drops in order to provide hotter water to the fin-tube and keep up with heat loss.

Running at a lower temperature with a 30 degree differential keeps the boiler from short cycling and having the ODR allows the temperature to rise to satisfy the greenhouse only when it is needed.

BTW: The greenhouse is for 200+ orchids and other plants and was necessary to reclaim a dining room where they previously lived.

I think running the boiler mostly up to 150 rather than always to 180 is saving some fuel but not enough to justify the cost of the ODR.
 
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