outdoor reset vs indoor reset

Reply

  #1  
Old 02-03-09, 09:30 AM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
Question outdoor reset vs indoor reset

This forum has been very helpful to me. I am a new home owner coming from a Manhattan apartment, so my knowledge is limited at best

Here are house specs
2300 sqft built in the 70's
burnham scg cast iron boiler (120btu)
Superstor 45 gallon indirect
2 heating zones plus the indirect WH
Baseboard heat along with a 4 toe kick heaters
We recently renovated the whole house (doors, siding, windows, insulation) so I think the house is pretty tight.

I am trying to make this system as efficient as possible (i think the boiler might be a bit over sized for my house)
Would my setup be a good candidate for an outdoor reset control? Being that I have the IDWH, wouldnt the boiler need hold a certain temp to satisfy the the water heater?

I have also read some decent things about an indoor reset (intellicon HW) Would this be a better fit for me?

What are the pros and cons for each?

If anyone could recommend something else that would help, please let me know. I just want to know that I am doing all I can to make this system as efficient as possible. Thanks!
 
Sponsored Links
  #2  
Old 02-03-09, 09:56 AM
Member
Join Date: Oct 2004
Location: PA
Posts: 1,901
Received 0 Votes on 0 Posts
Originally Posted by JayNY View Post
Being that I have the IDWH, wouldnt the boiler need hold a certain temp to satisfy the the water heater?
do a heat loss using the calculator on this page

Heat Loss Software - Slant/Fin Hydronic Explorer 2

How to get Hydronic Explorer 2

I'm a newbie myself but just had a new boiler with smart 40 tank put in. I was told the new tank is so well insulated that it barely drops a degree a day. So if you don't use hot water all day, it wont fire up to heat water needlessly. I can't wait until summer to actually test out this statement. It sure is better than my coil boiler.

I have a tekmar 260 ODR and love it. First few weeks i would always be checking out the readings. Seeing things like at 45 degrees outside i would only heat with 140 degree water but at 15 degrees it cranks all the way up to 170. Like a kid with a new toy. I can tell you in my system the ODR is wonderful but im not enough an expert to say it's right for your system or not. Plus my system was designed with it in mind for the install. I do love the new 'even' heat it produces though. I'm comfortable at 67 in the house now where id need it higher with the old boiler.

Ill step aside and let the pros evaluate your setup
 

Last edited by luckydriver; 02-03-09 at 10:11 AM.
  #3  
Old 02-03-09, 04:36 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Would my setup be a good candidate for an outdoor reset control?
Any boiler is a good candidate for outdoor reset. Whether it gets elected is another story though.

If you lower the water temperature to only that which is needed to heat your home, you will save. DO keep in mind that a STANDARD boiler with STANDARD piping can NOT use FULL reset. You can only lower the water temperature just so much before you start to have problems with FLUE GAS CONDENSATION (google it for more info). This is a SERIOUS issue that you want to avoid at all cost. You will have to set a MINIMUM temperature that the control is allowed to drop your water temperature down to, and this is going to limit possible savings... with a gas boiler I would be leary of allowing it to drop to much less than 155F on the SUPPLY side. You want to insure that the RETURN water comes back to the boiler no cooler than 135F to prevent condensation problems.

Chances are pretty good that many of the heat calls in your home are satisfied before the boiler actually reaches the high limit temperature.

Pay attention to the temperature gauge on your boiler... if it's usual behaviour is to fire up on a heat call, and heat the water to say 160 or so before the heat call is satisfied, you might not save all that much from a reset control.

As an example: during that really cold weather we had here a couple weeks ago in NJ... the HIGHEST temp I saw the boiler reach was 165... normally at outdoor temps of say 20-35, it rarely reaches 150 ... being a conventional boiler with conventional piping, I'm not gonna save a heckuva lot from adding an outdoor reset.

IF you re-piped your system ($$$$$) and added the proper controls to do FULL outdoor reset, you could save a bunch, but it would take quite a while to 'payback' that expense. If you plan to spend more than say 5 years in your home, you might consider it.

Being that I have the IDWH, wouldnt the boiler need hold a certain temp to satisfy the the water heater?
No. This would only be the case if you had a tankless COIL installed inside the boiler. Indirect water heaters are designed to operate with a cold start boiler. As far as the boiler knows, the water heater is just another zone. When the water in the indirect cools, it tells the boiler to send heat, I'm cold!

Keeping a boiler warm 24/7 for an occasional hot water use is a big waste of energy.

I have also read some decent things about an indoor reset (intellicon HW) Would this be a better fit for me?
I'm not sure that I would call the Intellicon an 'indoor reset' control. What it does is alter the 'differential' on the boiler when there is less load (warmer weather). In my opinion, based on experimentation with MY HeatManager unit, it won't really save you much unless you have a grossly oversized boiler that SHORT CYCLES. Meaning that it ROUTINELY heats up the water to the high limit, with the burner shutting down before the heat call is satisfied, and the burner firing AGAIN as the water cools... etc, etc... It is a very good solution for short cycling problems.
 
  #4  
Old 02-03-09, 05:44 PM
Member
Join Date: Feb 2009
Location: USA
Posts: 33
Received 0 Votes on 0 Posts
Oversize boiler?

Well, I'm a longtime homeowner with hotwater heat.
If that boiler did not run pretty much all the time when it got down to design temperature [the low you see about 2% of the time in a year] then it is oversized. Some over sizing gives quick comfort when you set it back up a few degrees after letting it be cooler to sleep. Don't set it back much though.
My place is the same size but older...1940.
I have the problem that, at design low of -17 degrees, mine [with a net output of 108,000 BTU/hr] only fired 57% of the time.
Naturallly this is worse in Spring as it warms up. So it cycles on and off a bit too often. Like the guy above, I'm looking at reset but more so, at a buffer tank full of water to give the boiler something to run longer and chew on , and then I would draw off the tank to heat the zones.
Have to figure out the controls.
 
  #5  
Old 02-03-09, 05:51 PM
Member
Join Date: Feb 2009
Location: USA
Posts: 33
Received 0 Votes on 0 Posts
I am new here. I replied to new home owner and it came out at the top of the thread. Oversizing, etc.
Take a look at heatinghelp.com. It's addictive...a group of competent hydronics and steam pros with a genial, patient host.
 
  #6  
Old 02-03-09, 06:06 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Top of the thread? Where? nuh-unhh, yer on the bottom on my screen!

Joe, have you looked at the "Boiler Buddy" ?

HeatingHelp is OK... not as 'homeowner' friendly as this place... they wouldn't tolerate well some of the questions that get asked here!
 
  #7  
Old 02-03-09, 06:56 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
Originally Posted by joewalbran View Post
I'm looking at reset but more so, at a buffer tank full of water to give the boiler something to run longer and chew on , and then I would draw off the tank to heat the zones.
Have to figure out the controls.
Very thorough way to do this is with a buffer tank and an injection mixing control like the tekmar 361. There are less complicated options, but if you want something off the shelf, that would do it.
 
  #8  
Old 02-03-09, 07:01 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
JayNY, I agree with NJ Trooper regarding choice of control, decisions regarding how far to go with potential repiping, etc.

That said, you could go with a tekmar 260 and be covered regardless.

(And having mentioned tekmar products in two separate replies, I will state that I have no interest in tekmar other than as a very satisfied consumer.)
 
  #9  
Old 02-03-09, 07:48 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Posts: 2,465
Received 2 Votes on 2 Posts
Hopefully your boiler is not maintaining temperature all the time. The SCG was not designed to maintain temperature. Cold start is the way to go even with indirect water heaters.
 
  #10  
Old 02-04-09, 08:02 AM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
Thanks for all your replys.
Last night I monitored the boiler temp. It never seemed to go above 160 degrees before shutting off. This morning however, it was going up to 190 and then shutting off. Maybe all the zones were calling for heat at the same time?
NJTrooper-with the risk of getting in over my head here, how would I know if I have the correct piping to do a "full" outdoor reset? Would you have a pic or diagram that I could look at? Would the outdoor reset also help with short cycling like the intellicon? It seems like the outdoor reset would give me more control than the intellicon (not sure thats a good thing)
I would I really know if I am short cycling? Its in the low 20s here today and the boiler is definitely not running all the time.
The plumber said the SCG is a cold start boiler, but how do I know is not maintaining temperature all the time? Even when its off for awhile the temp doesnt seem to go below 80 or 90 degrees before it kicks in again. But that could just be because the system calls for heat again!
 
  #11  
Old 02-04-09, 06:16 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
This morning however, it was going up to 190
If you are using setback thermostats, it's possible that this was due to recovery from that setback. There would be longer heat calls during recovery.

how would I know if I have the correct piping to do a "full" outdoor reset?
In order to do full reset, you would need a piping system that provides two distinct hydraulically separate piping loops. Google "PRIMARY/SECONDARY" for more info... What this means is that the boiler itself has to be able to run at appropriate temps, while the distribution SYSTEM is run at the lower temps... and in between these two 'loops' of piping, there would need to be some form of 'injection mixing' piped as a 'bridge' between them. I'll look for some diagrams later, but in the meantime do some independent research... the chances are 99.999% that you do NOT have the piping or boiler to do a full reset system. No contractor or installer in their right mind would spend the time or money to do so unless they knew they were getting paid for it.

Your system is most likely Hot water out to system, cooler return water back to boiler...

Would the outdoor reset also help with short cycling like the intellicon?
Yes... but PROPER SIZING of the boiler is the ultimate goal.

[How] would I really know if I am short cycling?
If your burner fires on a heat call and quickly runs up to the boilers high limit (say 180) in say 4-5 minutes or less, then shuts down for a few minutes while the heat call continues and the water cools a bit, and the burner refires for the same, and this process repeats several times before the thermostat satisfies, that's short cycling.

but how do I know is not maintaining temperature all the time?
It's in the controls... a 'warm start' boiler has a different control box on it that will fire the burner even when there is no heat call, just to keep itself warm. I doubt that you have that. Your boiler would have been supplied with the proper cold start aquastat installed from the factory.
 
  #12  
Old 02-04-09, 07:36 PM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
NJ Trooper-
You are correct. I just checked my boiler and I dont have 2 separate piping loops. No need to bother with the diagram, but thank you.
I am going to see if I can figure out if its short cycling.
I feel like I need to add the outdoor reset or the intellicon (I dont think there is a need for both?) I know the ODR is more $ than the intellicon, but assuming they were both the same price, which would you add to this system? What are the pros and cons for each? Since I cannot do the full reset should I not bother with the ODR? I just want to get the right add on and not kick myself for getting the wrong one.
Also, it seems even after the boiler shuts down the temp stays high for awhile. I guess the cast iron does a good job of holding the heat? I feel like I should be pumping that heat into the house! Thanks for your time.
 
  #13  
Old 02-04-09, 08:17 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
A decent, but by no means definitive, definition of short cycling is the boiler making 6 or more ignition attempts per hour. For example, that could be 5 minutes on, 5 off over an hour.

For your boiler, I would take partial reset with a tekmar 260 over an Intellicon/HeatManager any day of the week and twice on Sundays.
 
  #14  
Old 02-04-09, 08:42 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I feel like I need to add the outdoor reset or the intellicon (I dont think there is a need for both?)
No, certainly no need for both... and unless your boiler REGULARLY hits AT LEAST 170 on a heat cycle, the Intellicon isn't going to do a thing to help you... that is the temperature that MUST be achieved by your boiler before the Intellicon does ANYTHING for you. I know this is true from my experience with one...

An ODR unit, something like the Tekmar 260 may benefit you, but again, if your boiler doesn't spend much time above say 150 during a heating cycle, that isn't going to do much for you either, because that's about the lowest temperature that the 260 will 'target' anyway.

So, before you make your choice, spend some time getting acquainted with the way that your system operates. Watch it for the rest of the season when you have time to sit and babysit it. Spend some time researching what outdoor reset does. Then you will have some data to make an informed decision about what's best for your system.

I guess the cast iron does a good job of holding the heat? I feel like I should be pumping that heat into the house!
Yes it does. Pumping it into the house is an option with some added controls... but that may cause the house to overshoot the thermostat... leaving it in the boiler for use on the next heat call isn't really such a bad thing. I believe your boiler has a damper that closes when the boiler isn't firing? That will prevent most of that heat from going up the chimney.

You could end up spending a lot of money searching for that magic bullet that you hope will save 25% on your heating bills, and that is going to be difficult to achieve.

Do you have an expectation, or a goal, of what you think you might be able to save? Are you looking for 5% ? 10% ? or more? I know this may sound somewhat like I'm trying to discourage you, but that's not the case... just want you to know what is possible so you know what to expect, and where to best spend your money and time. Hint: insulate and seal air leaks more... when you think you're done, look again... if you don't have R40 in the attic, start there.
 
  #15  
Old 02-05-09, 09:15 AM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
My boiler seems to be hovering above 170 degrees more than I thought.
My plumber is recommending a honeywell ODR over the Tekmar (he didnt know much about the intellicon) He says the Tekmars are good (he has one in his house) but he feels the honeywell is easier for the homeowner to use. Any thoughts on this?

I believe your boiler has a damper that closes when the boiler isn't firing? That will prevent most of that heat from going up the chimney
I think so. Its power vented if that helps.

Do you have an expectation, or a goal, of what you think you might be able to save? Are you looking for 5% ? 10% ? or more? I know this may sound somewhat like I'm trying to discourage you, but that's not the case... just want you to know what is possible so you know what to expect, and where to best spend your money and time. Hint: insulate and seal air leaks more... when you think you're done, look again... if you don't have R40 in the attic, start there
I guess the easier answer is.... as much as possible but 10% would be nice.
I actually have someone coming on Saturday to give me an estimate on the attic insulation. (I doubt we have R40) That would be the last thing to do on that front. Everything else was done during the renovation.

To ODR or to intellicon....that is the question. I am leaning towards the ODR after Xiphias' post. Thanks again.
 
  #16  
Old 02-05-09, 04:53 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
but he feels the honeywell is easier for the homeowner to use. Any thoughts on this?
If you trust him, then go with his recommendations. Either one will do the job. (I would consider PRICE too... if the Tek is considerably cheaper, I would insist on it...) I'm sure you can learn to use the 260 with no problem... it's not crazy complicated. Does your guy think yer a dummy? I'm not familiar with the Honeywell unit, so can't say with any authority if it's easier, etc...

To ODR or to intellicon.
There's no question in my mind as to what my choice would be either... ODR all the way. But as I said, it depends on what you are looking for. All the Intellicon does is modify the differential on the boiler water temperature, based on what it perceives to be more or less 'load' on the boiler. It does this by sensing the rate at which the boiler water cools AFTER the boiler hits it's high limit, and as long as that high limit is ABOVE 170. If the boiler does NOT hit high limit, the unit does NOTHING AT ALL. During the 'shoulder seasons', spring and fall, the Intellicon won't help a bit... because your homes' heat calls will probably be satisfied long before your boiler nears the high limit. While this is where the ODR comes into it's own... an ODR unit KNOWS what the temp outdoors is, knows what the boiler water temp is, knows how fast it's heating and cooling, knows how hot the water needs to be to both heat your home AND protect your boiler, etc, etc, and modifies the boiler water temp AND the differential to suit... the Intellicon only knows ONE thing, that's 'how fast the water cools after a firing' ... but as I stated earlier, it's a good solution for short cycling systems. I would not expect to see the 10% savings they guarantee... in fact, I would be surprised if you see 10% with an ODR unit installed when running PARTIAL RESET. But, 10% ain't nothing to sneeze at with the price of fuel these days.
 
  #17  
Old 02-05-09, 05:18 PM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
He says the honeywell is about the same price as the tekmar. I just see the tekmar mentioned all the time and have not heard much about the honeywell.
Am I correct in think the ODR will give me longer run times at a lower temp and more even heat throughout the house? Does it do this by running the circ pumps longer? The ODR would help with short cycling as well? I assume the indirect WH will still have priority on with the ODR. If I have my water heater set to 135 degrees, the boiler cannot be set lower than that, right? When does thermal shock come into play with a cast iron boiler? Listen to me with the "thermal shock" lingo.....I have never used that term in my life before this
Thanks again.
 
  #18  
Old 02-05-09, 06:24 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I think you've probably heard more about the Tek stuff because it is in general more available to the general public... seems to almost have a 'cult following' ... and, it's BLUE... ppl seem to like BLUE!

No, not necessarily longer run times, but maybe... depending on what the control sets the 'differential' to...

Yes, the circs will run longer because the water is not as hot, and will take longer to satisfy the thermostat. Yes, the heating will be more 'even', more comfortable, less noticeable...

Yes, the 260 I know has priority for DHW...

In NO case would you want a conventionally piped gas fired conventional boiler to run as low as 135 on the supply out of the boiler! You WILL have problems with flue gas condensation! I would not run the supply on a gas fired boiler any less than 155 or so, and THIS is what limits the savings when using ODR in a PARTIAL reset scenario...

Thermal shock occurs when you have a HOT boiler and you dump a bunch of COLD water back into it... very bad! ... you can CRACK a boiler that way. This is different than a 'too cool' return temperature.

Pretty soon, you'll be throwing around terms like "delta T", "Flow rate", "Firing rate", or even BTU per SQUARE FOOT per DEGREE DAY! better quit while you still can! Beer 4U2
 
  #19  
Old 02-05-09, 06:56 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
Jay, I've had a tekmar 260 for three years and love it. It's running a Burnham boiler (Revolution) that is a bit fancier than the SCG so the control can do a bit more for water temperatures. But it's very cool and very efficient. Takes about 5 minutes to learn (there's only 3 buttons, and only two of them actually do anything), and once you get it dialed in right, you don't have to mess with it. Haven't changed settings on mine essentially since the day it first fired up.

The ODR will help with cycling. It will improve system performance and save energy. It will try to achieve more constant circulation and that will even out temperature swings in the house -- hugely!

The Honeywell AQ200 series is probably what your contractor is suggesting. The basic package is the AQ251, as I recall. It has essentially the same functionality as the tekmar 260.

I would go with whatever one you like or that your preferred contractor is better able to support.

The Honeywell is here:
AQ251

The tekmar is here:
http://tekmarcontrols.com/literature/acrobat/d260.pdf
 

Last edited by NJT; 02-05-09 at 07:21 PM.
  #20  
Old 02-05-09, 07:07 PM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
Well, I guess 155 is better than 175-190. And I like the sound of even heat. I think I will go for the ODR. Is there anything else I need to know?
Thanks for all your help.
 
  #21  
Old 02-05-09, 07:23 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
He said basically "close in price" between the two?

The list on the basic 251 model is over six hun... I'm pretty sure the Tek is quite a bit less than that. Of course you probably won't be paying 'list' for the 251 ... hopefully he'll cut a break on that... FYI, you can find the 260 on-line for a bit over three... prices vary widely!

I just found a place on the web with the 251 panel for less than the lowest price I found the 260 for, so I guess the price is close...

But there sure aren't that many retailers of the honeywell stuff!
 

Last edited by NJT; 02-05-09 at 07:39 PM.
  #22  
Old 02-05-09, 07:25 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
Yes it is. And you may be able to squeeze that down to 145 after you see how it performs over a couple months.

Anything else? Not really. The tekmar 260 also has a provision for an indoor sensor, which can further fine tune how the system performs. But you can always add it later (I added mine in the second heating season...). The Honeywell might allow for similar "indoor feedback."

If you want more background reading on the benefits and functionality of outdoor reset, check out the tekmar essays at

tekmar Essays
 
  #23  
Old 02-05-09, 07:29 PM
Member
Join Date: Sep 2008
Location: new york
Posts: 109
Received 0 Votes on 0 Posts
I like blue too. Seriously, Xiph and Troop know their stuff when it comes to odr and boiler temps. They made me too dangerous for my own good and helped me spend a considerable amount of money. But at the same time helped me save an even more considerable amount of money. Listen to them, they know what they speak of.
 
  #24  
Old 02-05-09, 07:39 PM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
Xiphias -

Thanks for the info. The blue tekmar is nicer looking
I will do my homework and make a decision.
I just checked on the attic insulation. Its R-11!
I guess I will be replacing that on Saturday. Ahhh...it never ends.....
 
  #25  
Old 02-06-09, 07:56 AM
Member
Join Date: Oct 2004
Location: PA
Posts: 1,901
Received 0 Votes on 0 Posts
Originally Posted by NJ Trooper View Post

An ODR unit, something like the Tekmar 260 may benefit you, but again, if your boiler doesn't spend much time above say 150 during a heating cycle, that isn't going to do much for you either, because that's about the lowest temperature that the 260 will 'target' anyway.
I may be taking you out of context and if so i apologize, but with my 260, on days that have been 45-55 degrees out, my target temp has been the minimum setpoint of 130 or 135 (he changed it his last visit to 135). So when i read that you said that 150 was the lowest temp the 260 would target, i just had to interject here to see if my low setpoint was in some way 'dangerous' for my boiler.
 
  #26  
Old 02-06-09, 08:06 AM
Member
Join Date: Dec 2007
Location: A Galaxy From Afar
Posts: 421
Received 0 Votes on 0 Posts
A gas fired boiler has a greater dew point temperature. Need to run it at a higher water temperature then oil to prevent condensation.

Al.
 
  #27  
Old 02-13-09, 08:30 PM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
So I had the Honeywell AQ2514B2 installed. I wanted the Tekmar but the installer pushed for the HW. Seems like a nice unit and it does pretty much everything the Tekmar does. It looks like if I add the HW communicating thermostats it would even give me more functionality (indoor reset) It also seems to have controls for an A/C unit which I will look into.

So now that I have this fancy thing, what should I do with it
Any recommended temp settings? I am sure the tech left everything at the defaults.
He said that I dont have to worry about condensation because I have a cold start boiler? Is that true?
 
  #28  
Old 02-13-09, 10:48 PM
Member
Join Date: Jan 2009
Location: Northwestern Ontario (Canada)
Posts: 549
Received 1 Vote on 1 Post
Originally Posted by OldBoiler View Post
A gas fired boiler has a greater dew point temperature. Need to run it at a higher water temperature then oil to prevent condensation.
Whats a good supply side (steady state) temp for an oil boiler(cast iron nipple) ? (mine's around 150 currently..)
 
  #29  
Old 02-14-09, 09:14 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
So now that I have this fancy thing, what should I do with it? Any recommended temp settings? I am sure the tech left everything at the defaults.

He said that I dont have to worry about condensation because I have a cold start boiler? Is that true?
Pretty much nothing to be done but allow it to 'learn' what it has to do. The unit will collect data over time and adjust it's settings to match the conditions. Read the manual, understand what a 'characterized heating curve' is ... play with the buttons, see what settings are in there (defaults?)... once you are somewhat familiar with what the control does, ask questions...

That is absolutely UNTRUE about not having to worry about condensation... under certain conditions, ANY boiler can be coaxed into condensing... and in fact, a COLD START system is probably MORE likely to condense than a warm start.

RETURN WATER TEMPERATURE. The water returning to the boiler from the system should reach a minimum temperature (say 135F for a gas fired, and 120F for oil) in a reasonable amount of time (say 5 minutes or so)... and the burner should continue to fire after this temp is reached in order to dry any condensate that occured while the boiler was heating up. Remember that the acids in the flue gas are INERT as long as they are dry.

Heating systems with FINTUBE BASEBOARD generally heat up fast and often are not plagued with condensation issues because the volume of water is fairly low.

Systems that use CAST IRON, either standing radiators or baseboard, and converted gravity or steam->hot water have HUGE volumes of water and that water heats slowly. These generally present 'issues' with condensation and should be dealt with by using proper near boiler piping techniques (i.e. proper bypass piping).

So watch the return temps... I believe a thermometer on the return pipe should be a mandatory item... but is rarely installed.

The BOIL MIN should be set appropriately on the control, check the install manual for suggestions.

Dave, the answer to your question... it depends, on the above info. Eyes on the return water temp.
 
  #30  
Old 02-14-09, 09:49 AM
Member
Join Date: Jan 2008
Location: Rhode Island
Posts: 116
Received 0 Votes on 0 Posts
Originally Posted by NJ Trooper View Post
RETURN WATER TEMPERATURE. The water returning to the boiler from the system should reach a minimum temperature (say 135F for a gas fired, and 120F for oil) in a reasonable amount of time (say 5 minutes or so)... and the burner should continue to fire after this temp is reached in order to dry any condensate that occured while the boiler was heating up. Remember that the acids in the flue gas are INERT as long as they are dry.
Assuming 120F is tthe lowest recommended return temp,
if I turn my oil boiler temp down to 120 for the summer will it be ok. It is a 63 year old WM.
 
  #31  
Old 02-14-09, 09:49 AM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
Thanks Trooper,

I do have fintube baseboard, but I will keep an eye on it regardless.
There is a sensor installed on the return pipe so I will watch that as well.
He forgot the sensor for the indirect so he is coming back for that.

What temp should I set the aquastat in the boiler too? I assume that this would be the high temp setting and the ODR control would use that as its max temp?
 
  #32  
Old 02-14-09, 09:56 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Jay, the aquastat on the boiler should be left at appx 180 or so... this will actually become an 'auxiliary' high limit with the ODR control in place. REALLY cold weather the boiler may still fire up as high as the aquastat setting... and if you are using an indirect fired water heater, that will be the control setting for it...

Again, there should be instruction for this setting in the HW manual.

Angelo, if you are using a tankless coil for domestic HW, you absolutely do not want to set the aquastat at 120... you won't get any hot water to speak of... AND, don't forget that setting is for the SUPPLY side... it's the RETURN you need to be concerned with... if summer use is for domestic HW only, 140 might be a reasonable setting.
 
  #33  
Old 02-14-09, 10:28 AM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
I have read through the manual and can't find much about the boiler temp setting. I will leave it at 180 for now. The manual does not have much info in it at all. (ex. It has a setting for "purging" but doesn't tell you why you would need to use it)

I am noticing more water noise in the baseboard when the heat kicks in. He did add a grundfos pump during the ODR install to separate the zones. Previously, I had 1 pump feeding 2 zones. Maybe he didn't get all the air out of the system? Would the purge help?
Thanks.
 
  #34  
Old 02-14-09, 01:50 PM
Member
Join Date: Jan 2008
Location: Rhode Island
Posts: 116
Received 0 Votes on 0 Posts
Trooper,
I no longer use my boiler for domestic HW. So is the 120 temp OK? The reason I ask is last year I shut it down for 5 months in the summer and the restart was a disaster with an acrid steamy smoke that required a visit from the local FD to clear the smoke so the alarm company would stop calling me. I called my boiler tech in and he recommended leaving it on and lowering the temp to 120. The other alternative was to pay him $120 to clean it before I refire for the winter.
 
  #35  
Old 02-14-09, 04:47 PM
Member
Join Date: Sep 2008
Location: new york
Posts: 109
Received 0 Votes on 0 Posts
Jay, just to add my 2 cents. I just recently did a system with the help of a lot of the regulars on here and it is running beautifully. In regards to the aquastat setting, I have a Tekmar 361 controlling things and it says to set the aquastat 20* higher than the design temp of the system. With fintube baseboard the design temp is usually 180*, so the aq would be set at 200*. Thats what I have mine set at anyway.
Troop, Xiph, what do you think? Could that rule apply here too?
 
  #36  
Old 02-14-09, 08:03 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Jay, did the installer leave both the user AND the installer manual for you? The user manual has no info on the installer 'menu'...

Installer manual

After reading through the manual, I'm finding that the HW unit has some options and settings that Tek doesn't have... for example, if you were to install a 'pumped bypass', your control would turn that pump on/off depending on the water return temp and provide boiler protection.

Settings you might want to check:

OUTDOOR LOW - make sure that's set for the 'design temp' in your area... there's a chart at

Outdoor design temps

BOILER DESIGN - might bear some experimentation... that's the temp that the control would target AT your 'outdoor low' temp. You may or may not need 180 water to heat your home at design temp. A room by room heat loss and measuring your baseboards would help decide that setting. You would have to find your 'worst case' room, the one that has the least baseboard relative to heat loss, and determine what temperature water you would need to heat that room, then adjust this setting to match.

HIGH LIMIT - default is 190 - You would want to set the boiler aquastat a tad above that setting.

LOW LIMIT - probably don't want to decrease this below the default of 150, and at that, try to keep an eye on them return temps... if the delta T on your system is 25 degrees, you might run into trouble eventually. You might end up bumping this temp a bit based on your return temp...

Angelo, you _might_ be OK with 120... since you aren't circulating any water... set the DIFF high enough so that the boiler fires for at least 5 minutes or so... start with maybe 20 DIFF and see how that goes.
 
  #37  
Old 02-16-09, 10:08 AM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
Trooper,
Ah, the installer manual. Thats what I needed. Thanks!
I dialed everything in a few days ago and I have to say, the ODR is already making a BIG difference in the comfort of the house. I thought it was my mind playing tricks on me because I knew it was there. Kinda like when you wash your car, you think it runs better
Before the ODR, we used to keep the thermostat around 68-70 during the day, and my wife thought it was too cold in the house. At night we used to turn it down to 66. Well after the ODR I turned it down to 66 at night and didnt realize we never turned it up in the morning. We were comfortable in the house with it at 66 all day. Never knew until I happened to walk by the thermostat. I even asked the wife if it was cold and she said no. And she has no idea about the ODR She thought the therm was set to 71 or 72!
So either this thing is really doing its job or we are going crazy. But the house is more comfortable at 66 than it was before at 70.
I am going to tinker with the honeywell some more and might consider upgrading to the communicating thermostats.
Needless to say, I am very happy I went with the ODR over the heat manager. I cannot imagine it making this much of a difference.

Thanks for everyones help!
 
  #38  
Old 02-16-09, 04:14 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I think a big part of the extra comfort comes from the evening out of the temps... the temp probably stays in a closer band because of the longer flowtime of cooler water... instead of 'bursts' ... yeah man, gun it up to that next red light! then slam on the brakes...

Did you install the indoor sensor? I believe that's optional on your control? If not, do it if you can...

Did I read correctly that your control can also run a variable speed (VS) pump?

Know what else I liked about that control was the integrated zoning controls... expandable... I might have to get one of them myself someday!

Do keep an eye on the return temps though... and if you see whitish streaks appearing on the flue connector pipe, like water running out and drying... you know yer condensing... and turn up the BOIL MIN ... or what does Honey call it? LOW LIMIT or somesuch?
 
  #39  
Old 02-16-09, 08:39 PM
Member
Thread Starter
Join Date: Feb 2009
Location: North East
Posts: 14
Received 0 Votes on 0 Posts
I did not install the indoor sensor yet. I think what I need to do is just buy the communicating thermostats which have the indoor sensors built in.
Thermostats

Yes. It does support a variable speed pump and has some pretty neat zone controls. Its also expandable to 64 zones! Maybe my next house (you can bet I will take it with me)

One problem with the control that just surfaced...We installed the DHW sensor (the installed forgot to bring it the first time) and now cannot see the return temps. The manual seems to say its one or the other, not both. If you look at the Installer manual
on page 36 you will see what I mean. So at this point the return temp sensor is disconnected in favor of the DHW sensor. Now, there is a min return setting in the menu's which I have set to 135 (see page 31) But I am not sure how that could mean anything if the sensor is not connected. Am I missing something here? Or is this just the way it is
 
  #40  
Old 02-17-09, 01:44 PM
Member
Join Date: Oct 2004
Location: PA
Posts: 1,901
Received 0 Votes on 0 Posts
Originally Posted by JayNY View Post
So either this thing is really doing its job or we are going crazy. But the house is more comfortable at 66 than it was before at 70.
not crazy at all. I just had a tekmar 260 put in with a new boiler and i've been 'dying' at 66 at night at times. I had to adjust the setback for 65 while sleeping. I cant imagine what 70 degrees would feel like with this system.

i love seeing the 130 water temps on 45+ degree days. I look forward to getting my next few oil bills!

sick i know

and when you try to explain to someone that 'today' is a much different 67 than last year, they look at you like youre nuts
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: