Benefits of Munchkin in non-radiant House?

Eric Peterson_3

Like LIRR, I am a homeowner looking for a replacement boiler for my older house, which is a converted gravity system with cast-iron baseboard plus free-standing radiators. A LOT of water and LOT of radiation. I might even coin the term "vast iron" to describe it. There are three zones in my system by the way.

Anyway, unlike LIRR I have no objection to condensing, unless it is clear that I will not reap the benefit of the claimed 92% rating. The Munchkin is light, efficient, and looks easy to install compared to some of the middle efficiency products available (such as the Revolution). Yes I could (and may well end up doing so) install an 81% atmospheric and be done with it, but the tree-hugger in me plus being the guy paying the gas bills does not care for that solution so much.

So, from an operational point of view, is the Munchkin an appropriate fit or not? After reading Sigenthalers book last year I had convinced myself that condensing did not apply in my situation, but now I am not so sure.

Does anyone have any data on this question?

Thanks,
Eric Peterson

Bryan_16

no data

to share, just experience. The Munchkin loves large mass systems, it thrives on low return water temperature. With all your "vast iron" the Munchie will go 92+. Install a Vision 1 package(outdoor reset) and your gas bill will shrink considerably.

Eric Peterson_3

OK, but return temp not always low due to setback

With my present setup I setback the temperature at night, which means that on colder mornings it may take a couple of hours to raise the house back up from the setback - when running that long the water temperature may actually trigger the high limit (160 typically).

Now I know this setback (5 or 6 degrees) is a kind of false economy, so I (and especially my family!) would be willing to lessen or eliminate it if I knew the boiler was running inefficiently during this catchup phase.

Thing is, my house is now pretty well insulated (with a few exceptions) compared to when the vast iron was installed, so I have way more radiator horsepower than I really need, thus most days, especially if the setback is excluded, the water temperature will not approach the high limit. Well maybe if it gets to -30F.

Even so, I would like to know the efficiency curve for the Munchkin as the return water temperature increases. Has anyone seen such a curve?

--Eric Peterson

Ted_9

If you havent done an acurate heat loss on the house, do so.

Then size you radiation.

Then you can start to figure out what boiler stategy you can use.

Patriot Heating & Cooling, Inc.

chuck shaw

Eric

We do not have a curve for the benifits of running a condensing boiler. All boilers are tested to meet the same standard, which is at 160*F, out of the condensing area. However, having said that, a condensing boiler is designed to operate at much lower temperatures. If you do a heat loss on the home, and realize that you will be able to heat your home, and be comfortable, with water below 140*F, at any point in the heating season, you may see benifits from the condensing boilers.

No one will give you a chart that will estimate your savings, because every home is different. I have tested Munchkins, that were running with very cold return temperatures, (below 32*F), and on my combustion analizer, got a reading of 100% efficent. Can you expect this? Probally not unless you are running snow melt.

After doing a heat loss, and checking the heating curve, if you can heat your home, thru large cast iron radiators, with a fairly low water temp, then a condesing boiler will benifit you. If not, and you have to run above 150*F to heat your home durring the fringe seasons (fall and spring), the added expense may not be worth it.

Either way, to get valid answers, you or your contractor must do the math.

If you wish, you can call me tommrow, and I can give you additional information

Chuck Shaw
Technical Support Department
Heat Transfer Products
508-763-8071

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Unknown

Eric

As stated below by Chuck as well as others, you will not appreciate the "full" benefits of condensing boilers unless you have situations with cool enough water to make them condense. The Revolution is not a condensing boiler, but simply a boiler that modulates flow of water through the boiler to allow it to adapt to varying system water temperatures. It indeed is NOT a complicated boiler to install and service. It has a simple tube type burner gas train and conventional controls. Piping to the system is as simple as it gets with a supply and return, gas and electric. I might add that we have about 32 pages of various venting configurations to adapt to just abouut any situation. Hope this helps.

Glenn Stanton

Burnham Hydronics

Eric Peterson_3

Thanks for the offer

I have done a heat loss calculation some years ago....have to go and look for it. What I don't think I have done is calculate the output of my radiators. I've got some 6" BaseRay, 9" Weil McLain, as well as 9 free-standing radiators.

Anybody know the heat output for 6" BaseRay or for 9" Weil McLain baseboard radiators? How about where to go and look for data on free-standing radiators?

I will need to collect some data as you say before and do the math before I call.

I will say that in the spring and fall my return temps are typically less than 120 for sure. In the winter it tends to run longer cycles, i.e. there will be a long call for heat followed by a long period of inactivity as the heat in the system is slowly released...room temperatures tend to be right on the money though.

--Eric Peterson

Eric Peterson_3

Burnham installation

I know the piping is very simple for the Revolution, I have read through the installation manual (you sent me a copy two years ago). Yes I have been fence--sitting for some time now. But this is the year I feel I should do something.

What I meant by easier installation for the Munchkin was a) PVC pipe for the exhaust rather than the special stainless piping needed for the Revolution, and b) the relative ease of moving a 100+ pound object down the stairs versus a 400+ pound object.

The Revolution does seem well-suited for my situation though, and would like it might be simpler hence more reliable. I think the Munchkin may require some primary-secondary piping IIRC.

Thanks for the information.

--Eric Peterson

Ted_9

You can find the information on the radiators on this site in the Library section.

ScottMP

Vast Iron

I like that..

I would think that, if you where set back you would be getting colder water back. Would'nt that get you into condesing mode ? Using a reset curve you will be getting heat out of that "vast iron" at lower temps so you might not be running that long most of the time. Sure during the coldest months you may be runnig for a longer period of time, but during the shoulder months which make up the majority of the heating system, I would think you would be operating in or close to the condesing mode.

Chech your prices, I think you'll find the munchkin is not that much more money, you'll probable recoup that the first year if not two. Remeber when you come out of set back thats ALOT of cold water going back to the munchkin and I doubt you will be goin to 160/180 that often.

Scott

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Darin Cook_3

High Mass High Volume

The Munchkin is ideal for that type of installation. You would most definetely want the Vision 1 control. This would give you the benefit of outdoor reset and other features. The radiation was oversized to begin with, not to mention all the work that has been done on the shell of the structure. What happens as the surface area of a radiator increases, the needed fluid supply temperature decreases (i.e. radiant floors). This means you probably do not even need to approach 180', maybe on the coldest day of the year. I agree with Scott completely. The boiler for all of your shoulder seasons, fall and spring, will operate in the condensing mode. Do not setback your system so far at night. Programmable thermostats with large night time setbacks were designed around Forced air systems, (low mass=air). You are more than likely increasing your energy usage setting back so far. If you want to set back only go a few degrees. The system was originally gravity, which meant it had a slight Constant flow of water. That gave the home even constant temperatures. High mass systems respond very slowly. Better to keep it at the same temp.

Remember too, the Munchkin has thermistors on the supply and return. It senses those temps and will only put in the heat that is needed. Not for nothing, but even if a Munchkin was tied onto a hw baseboard system. Check the stack temps, you can hold your hand over it. Go hold your hand over the stack of a cast iron boiler. Only for but a second, then you would have to brought to a hospital. My point is that the Munchkin transfers the btu's being produced into the water, not up the stack. It vents with PVC. The Munchkin will pay you back and the payback will not take long. I have seen this many times and I am sure Scott has too, the Munchkin saves you money. Hope this helps.




Darin

Ken_8

Totally Agree!

The Munchkin will be an absolute home run in this application. Just to make sure it is the very best situation possible, use an indirect water heater with it as well.

Can you spell HOME RUN WITH BASES LOADED?


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R. Kalia

condensing

> Even so, I would like to know the

> efficiency curve for the Munchkin as the return

> water temperature increases. Has anyone seen such

> a curve?


A zero-order approximation to such a curve would b 92% if the return temperature is above 130F, 85% above it. Now the main question is, what water temperature do you need on a very cold day? From your post, it seems like you do not need even 160 because you have an excess of radiation(to me this means there are harmful rays in the house, but apparently hydronics people use it to mean too much radiator area). So with outdoor reset, your return temperature will drop into the condensing range a lot of the year. It seems like you have the ideal setup for a condensing boiler. Make sure it is set up to circulate continuously.

Kal Row

most peoples experiance has shown

that condensing boilers - even when run in non condensing applications still give you about a 5% increase in AFUE over cast iron in the same application (unless your cast iron setup happens to have primary/secondary/vari injection a-la tekmar 362)

this has been especially true of the WeilMclain ULTRA with the lightning fast heat transfer property of it's aluminum heat exchanger – so if you can afford the munchkin – go for it – it’s a great little boiler - and cute too - the ladies love it

Munchkin - "ahs-tr-ayy-lian for boilarr" they should get Paul Hogan to do the commercials

Mark Hunt

Correct


I would add that while an accurate heat loss is important, it is only half of the equation.

Compare the heat loss to what your connected radiaton is. More than likely you are over-radiated. Not a bad thing!

I have quite a few Munchkins connected to cast iron systems, and in EVERY case, the customer has realized considerable savings.

As Darin mentioned, stack temps mean a lot. I have NEVER seen a stack temp higher than 115 degrees with the Munchkin.

Mark H

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R. Kalia

improving efficiency

Heat Transfer Products seems to think that its Vision I control documentation (distinct from th Munchkin boiler documentation) is a trade secret. Insist (before signing a contract) that you must be given a copy. You will need it to set the reset curve as low as possible, based on subsequent experience. There is no way your contractor can set it just right for your house, so he will probably set it too high so that you will never be cold. But then the benefits of condensing are reduced.

I also want to elaborate on what LIRR said about continuous circulation. Outdoor reset gives you lower water temperatures, which means the circulator runs longer. However, it usually does not run 100% of the time, because the thermostat is set up to stop it if the room gets too hot. Unfortunately, in your very-high-mass system, huge amounts of warm water then get stuck in the pipes, where they release their heat to where heat is not needed. To recover this energy and thus squeeze out a few % more efficiency, your circulator needs to run ALL the time (except summer). Control temperature by connecting the thermostats to 3-way zone valves: see Siegenthaler's article:

http://www.pmengineer.com/pme/cda/articleinformation/features/bnp__features__item/0,,113669,00+en-uss_01dbc.html

R. Kalia

I meant 92% if BELOW 130F, 85% if above it.

jerry scharf_2

another vote for condensing

Eric,

It's a common misconcepion that because the design temperature was 160 degress 20 years ago that a condensing boiler won't work.

A couple things to understand. It's the return water temperature that controls the condensing, not the output temperature. There's a rough rule of thumb that for every 3 degrees of return drop you get another % of efficiency from the condensing boiler. That's probably a overstatement of the gain, but it gets the point across.

So if you get rid of the setback and use outdoor reset, the efficiency gains in the boiler should more than cover the setback gains. Now the tree hugger can go after the low water return temps and squeeze the efficiency out of the system.

Get someone who understands this stuff to design the system for you. The devil is in the details!

jerry

Chuck Shaw_2

Vision 1---Trade Secrets

Vision 1 is not a trade secret, anyone is welcome and everyone is encouraged to come to the training and learn. We are very excited about our products and differant applications that they can be used in.

The reason we require training is that not all people are familiar with the concept of outdoor reset (most wallies are an exception, as are many homeowners who come here). We want to explain the benifits of this to them, ensure they understand how to program the control and realize, that if the programing is incorrect, it can cause dammage (think 180*F) water going through a slab, or in direct contact with a hard wood floor.

Also, space heating is not the only application that can benifit from the 925 control, with Vision 1. There is also domestic hot water, and limits can be changed with access to the proprietary control.

Keeping the Vision 1 programming proprietary also gives a slight edge to the contractors who have shown intrest in our products, we feel we should give something back to them, thus the limited access.

If the contractor wishes to give you access to the control, and you insist on it in a contract, be prepared that he may insisit that he be removed from liability issues, including property dammage and scalding.

Please realize, that Vision programming is not a trade secret, if it were we would not have built our new training center, nor would I feel like I should be nominated for Southwest Airlines customer of the month.

Chuck Shaw
Technical Support Department
Heat Transfer Products

R. Kalia

but HOs can't be expected to attend training session

OK, I was being flippant when I said "trade secret". But we homeowners arn't going to go get HTP training.

As I said earlier, no contractor can set the reset curve perfectly, so they will set it too high. The HO has to monitor actual operation through the first winter and lower the reset curve for increased efficiency if possible.

What's the big deal? You can do it with Tekmar products; their docs are all on the web. Tekmar doesn't make you sign a form waiving liability.

ScottMP

Why would

you have a thermostat with constant circulation ??

The two don't go together.

Also When we install outdoor reset we come back and make adjustments as neccesary. I would never expect a customer to adjust the heating curve.

I agree with HTP. I would not want every Tom,**** and PDQ fooling with a control and then going on websites and bashing a product.

Scott

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Kal Row

tekmar 512 two stage

first stage operates the zone circulator, which evens out the temps in the zone - may even open and run the system circ to extract heat from boiler or other zones

the second stage actually calls for heat production

us gov studies have shown that "two stage" buys you the most saving of all - expecially if your boiler is also usd for DHW - then there is usually enough residual heat in the system to satisfy first stage needs

Chuck Shaw_2

We dont require that anyone

sign a libility waiver. It was just something that may happen. We have somewhat different paramaters in our control than Tekmar. We also have some areas in our control that are marked not used, but are changeable, changing these could cause lock out or no heat situations. Therefore resulting in a no heat call back, for the tradesman. We give him the benifit of our experiance, so that he doesnt make this mistake.

Also, to my knowlage, and I may be wrong, tekmar doesnt give you the option, to tie a sensor directly to the boiler, and progam the domestic hot water temperatue (not just priority) from the boiler. If this number were changed, this could result in scalding.

I agree that no one will set a heating curve perfectly, the first time, every time. What could be done also, is that you include in your contract, that you expect your contractor to come back so the heating curve has may be checked and tweaked a couple of times. If you work this out with your contrator ahead of time, you can set up a meeting and you can work it out together. If this is a replacement boiler, he will want the heating curve to work in all rooms, which may mean that if some of the rooms were under heated, he would have to make the curve work there, as well is in rooms that were sized properly. (Of course, if this were severe, it may require other options.)

There is no big deal, it is the choice we made, to keep the Vision system propriatary to people who choose to attend training, if he chooses to give it away, that is his call. When we set up the Vision program, we gave our word, that only those trained by the factory or by our authorized representives would be authorized to program the Vision control. Up to this point, we have kept our word to them, and that is the plan for the future.

Chuck Shaw
Technical Support Department
Heat Transfer Products

Kal Row

i like to have smart customers

with the advent of vendor web sites with all the info readily avail - it saves me time from explaining things to the smart ones

indeed - i have HO's that know more then some plumbers and defiantly more then GC’s, General Contractors give me the most grief –

I don’t think any of it should be secrete – I get paid for my engineering expertise and neat installs – I do a start of season call for free and my contact info is clearly visible right on my installs – I have unfortunately not yet had to luck of getting a munchkin install - but I look forward to it, and if the HO happens to be savvy – I will educate them on every detail


– never lost business by sharing my knowledge

Kal Row

i like to have smart customers

with the advent of vendor web sites with all the info readily avail - it saves me time from explaining things to the smart ones

indeed - i have HO's that know more then some plumbers and defiantly more then GC’s, General Contractors give me the most grief –

I don’t think any of it should be secrete – I get paid for my engineering expertise and neat installs – I do a start of season call for free and my contact info is clearly visible right on my installs – I have unfortunately not yet had to luck of getting a munchkin install - but I look forward to it, and if the HO happens to be savvy – I will educate them on every detail


– never lost business by sharing my knowledge

Chuck Shaw_2

Kal

Please let me repeate myself,

IT IS NOT SECRET!!!!

There is nothing there, that is not general knowlege in the heating comunity.

Anyone may get access to the knowlege by attending the the class.

Is Calculus a secret?? No, but to learn it properly, you must go to class.


Chuck Shaw
Technical Support Department
Heat Transfer Products

ScottMP

Well Said

Chuck

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Eric Peterson_3

Continuous Circulation - not a good fit for my house

In order to heat all portions of my house comfortably, over time I ended up dividing the house into three zones - only one of which utilizes TRVs on some of the radiators. Since I am satisfied with this arrangment (can maintain comfortable temps) and do not wish to add additional TRVs, continuous circulation does not make sense in my case.

Taking this a little further, given that the house is now evenly heated (using the three zones and their corresponding thermostats), I am focusing *only* on the replacement of the source of hot water (the boiler) with a unit that is more efficient. I plan to keep the near boiler piping (3 zone valves with 1 circulator) unchanged.

A simple sort of outdoor reset might be worthwhile for the one zone where the room can overheat a little during the shoulder months (but since it is the family room no one usually complains about being too warm). Something like Vision 1 might be overkill for my situation.

--Eric Peterson

Kal Row

there is still no reason

why the info on you web site is not as open as tekmar's

i went to collage to get a degree, i learned everything from books myself - i went to IBR class to get interactive questions and answers – I want to read it all before I get to a class, my attention span is to short to learn it all from scratch in a class – and I sure I’m not alone being 50

Darin Cook_3

No Overkill

The Vision 1 for what it cost will pay for itself many times over. We do not even make it a option on our installs, it just goes on. It will also make the home even more comfortable. No need for constant circulation. Since you have zone valves, they are the flow checks and will not allow any circulation when they close.





Darin

R. Kalia

huh??

If you don't have essentially continuous circulation, that means your water is too hot. That means you don't get the full benefit of condensing, and you my also lose because of short cycling. Outdoor reset maximises your efficiency by keeping the water temperature as low as possible. Isn't that what you are looking for?

The switch from almost-continuous to 100% circulation eliminates noise in pipes, and also prevents energy loss from hot water sitting in the pipes, as PDQ has pointed out.

If you say you want high efficiency but you don't need outdoor reset, well, it sounds like you need to keep learning.

R. Kalia

why TRVs?

> In order to heat all portions of my house comfortably, over time I ended up dividing the

> house into three zones - only one of which utilizes TRVs on some of the radiators. Since I

> am satisfied with this arrangment (can maintain comfortable temps) and do not wish to add

> additional TRVs, continuous circulation does not make sense in my case.


"Continuous" circulation doesn't require adding any TRVs, although there is no problem with the TRvs you already have. You get (almost)continuous circulation by lowering the water temperature with outdoor reset, while still using the thermostat as you do now. Now the calls for heat last much longer. You're interested in increased efficiency, right?

Fully continuous circulation, as described by PDQ, does not require TRVs either. It uses three-way zone valves, one for each zone, each connected to the thermostat for that zone.

Eric Peterson_3

Re:Huh

I responded to your earlier post before reading the Sigenthaler article - it looks interesting but the pictures were missing, so I did not get the full gist.

The whole point of my query is to determine the applicability of the Munchkin to my situation, keeping in mind that I do not want to make too many changes. If indeed my return water is "too hot" for the Munchkin, then I may well go with the Burnham rather than replace my existing zone valves and possibly make other changes.

Hot water sitting in pipes has not been a problem to date for me, nor has short cycling.

The way I see it my current inefficiency is due primarily to a) heat lost up the flue when my inefficient boiler is firing, and b) heat lost up the flue when hot water is sitting in the boiler jacket doing nothing (yes continuous circulation could help here, but so could direct vent or a boiler with a minimal jacket).

I do want high efficiency but not necessarily at the cost of making too many changes at one time...as far as learning I don't plan to ever stop doing that. There are many informed people on this list but no one has all the answers as far as I have seen. Assuming I get a new boiler this year then next year I might tinker with continuous circulation and/or 3-way zone valves.

--Eric Peterson

Jay_12

Efficiency Chart

The attached chart in PDF shows the efficiency of Cleaver Brooks Clearfire commercial condensing boiler. It is the only efficiency chart of a boiler on the internet to the best of my knowledge. Of course, all boilers will have different curves, but this will give you an idea of the general trend.
A condensing boiler will not give you significant efficiency gains if it operates over the condensation point (around 140F).
In all cases an outdoor reset control will improve System Efficiencies by operating the system at lower temperatures.

A good website on boiler efficiencies can be found here:
http://www.cbboilers.com/Efficiency1.html#14

And no... I don't work for Cleaver Brooks.
J

chuck shaw

A couple of things

First---Vision 1 includes (you choose to install it) an outdoor sensor that will allow you to incorperate out door reset. Also, having met Misters Cook and his partner in heat, Mr Hunt, I believe that between these two men, they have fogotten more about heating than most people will ever know.

Second---I have been following with interest, a few things in this post. It seems to me that Chad from HTP has made it pretty clear, that they gave their word to their customers about something. They (HTP) for whatever reason, have chosen to present their controls in the way they see fit. They do things their way, Tekmar does things the way they choose to. Why is that so tough for anyone (age is not relevent) to understand. A Tekmar control will work with (almost) any boiler, Vision, as I understand it will only work with Munchkins. If I am incorrect in this I am sorry.

I apoligize to anyone that I may have offended, but some times, when an explaination, seems perfectly clear to me, I don't see how others can't follow it.

Rebel

R. Kalia

I suggest that you learn about this some more before doing anything. What I'm saying here is not a controversial issue; it is generally accepted and considered obvious.

If you insist on using high-temperature water in a "bang-bang" (constant on-off-cycling of very hot water) configuration, then you are wasting your money getting a Munchkin. The Vision I costs about $200 more. It is false economy to skip it, and a responsibl contractor won't install a Munchkin without one.

On the other hand, if you get a standard cast-iron boiler now, then you need bang-bang to protect the boiler, and you can't talk about making further changes down the road. A standard cast-iron boiler is not capable of running below 140F, so you can't do any useful outdoor reset.

Outdoor reset saves energy. And condensing boilers (which save energy as well) are well matched to the combination of outdoor reset plus a house with excess radiation, like yours.

Darin Cook_3

Another Tidbit of Info

Looking through the above posts, I have seen that a chart of efficiency for the return water temps was desired. ANY boiler begins to lose points on the efficiency as the return water temps climb. The Munchkin differential can be programmed as far apart as you would like. A post purge after a heating cycle can be programmed to allow the boiler to dump heat into the indirect tank. The burner will not even fire immediately if the system is still in the programmed design temps. Not to mention, the unit is sealed combustion. What are the efficiency increases to the home, if you are not constantly aggravating the amount of air infiltration coming into the home. Air that is absorbing heat and moisture and then going up the chimney of the atmosperic boiler. Or increasing the stack effect of the entire home. Noone has a chart to show the efficiency of a modulating burner either. But do you really think a boiler firing at a fixed rate, probably with a aquastat that has a built-in 20' differential can compete with the modulating type? If you do not want to buy a Munchkin, Don't. But the Laws of Physics are black and white, no gray areas. Just because someone did not study law, does not mean they still do not apply.




Darin

Dave Yates (PAH)

Both boilers

offer great value. I have a Burnham Revolution and a Munchkin in my home wired and piped to work independently or in tandem.

Both have proven to be trouble free.

If you want to drill down into the finite details of which one will ultimately give you what you're looking for, you'll need to do an accurate heat loss and, from that, determine what output capacity you've got on a room-by-room basis, which can be determined by the lineal feet of cast iron baseboard. Once done, you'll know what water temperature is required to offset the heat loss on a design day and that will also give you an understanding of how much "excess" capacity remains if you need to raise water temps to offset unusual weather conditions.

But that's based upon a design day, which will likely see temperatures higher than needed for condensing mode. You'll need to determine the "tipping point" where outdoor air temperatures, while using reset, will keep return water temps below the condensing threshold.

With a bit of work, you can extract degree day information from local weather stations or utility companies to determine how many condensing days you'll see in an average heating season.

Then you'll need to calculate efficiencies for annual fuel utilization and compare the two products.

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Weezbo

R. Kalia

> First---Vision 1 includes (you choose to install

> it) an outdoor sensor that will allow you to

> incorperate out door reset. Also, having met

> Misters Cook and his partner in heat, Mr Hunt, I

> believe that between these two men, they have

> fogotten more about heating than most people will

> ever know.

>

> Second---I have been following with

> interest, a few things in this post. It seems to

> me that Chad from HTP has made it pretty clear,

> that they gave their word to their customers

> about something. They (HTP) for whatever reason,

> have chosen to present their controls in the way

> they see fit. They do things their way, Tekmar

> does things the way they choose to. Why is that

> so tough for anyone (age is not relevent) to

> understand. A Tekmar control will work with

> (almost) any boiler, Vision, as I understand it

> will only work with Munchkins. If I am incorrect

> in this I am sorry.

>

> I apoligize to anyone

> that I may have offended, but some times, when an

> explaination, seems perfectly clear to me, I

> don't see how others can't follow it.

>

> Rebel

ScottMP

As described by PDQ

you are correct.

But there is more than one way to do constant circ. The most common is with TRV's in which you recieve the full benifit by individually zoning rooms or each heat emmiter. By using thermostats and three way zone valves you have a bang-bang approach to constant circulation where as TRV's tend to open and close slowly.

Almost constant circ is NOT constant circ. Its like almost pregnant.

No design is written in stone with Hydronics and to state so is'nt true.

Also constant circ. is Not outdoor reset. Each can be done individually of each other, allthought they certainly complement each other.

Theres more than one way to skin a cat and they all get the job done.

Scott

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