Heating systems

Greg_23

BUDERUS GB142 WALL HUNG BOILER WITH ALMOST ANY INDIRECT. THE PUREPRO INDIRECT "PLUG N GO" OR "PIPE N GO" IS A GOOD CHOICE BOTH HAVE A DUAL S/S COIL AND THEY ARE PRICED RIGHT AND THE COIL CAN BE INSPECTED, CLEANED OR REPLACED IF NECESSARY.

Eileen Olive

HEATING

We live in a two story 1400 sq. ft. house and my husband is installing a new Mod/Con boiler but can not decide between an Ultra-80, Contender or Knight. What do you suggest ? Also, what do you think would be the best indirect 40 gallon HW for this situation ?
We currently have an oil fired Weil McLean from the 1950s.
Thanks for your help.

ALH_4

Choices

Among those three choices, I would select the Lochinvar Knight and a matching Lochinvar indirect. Is this natural gas? If it happens to be propane, the mod/con may cost more to run than the 1950's oil boiler.

Brad White

Personally

among those you suggest, I would go with the Knight, but it also gets down to which offers the best local service. Others have opinions based on their own experience, you just wait.

My toggle of opinion goes to "use stainless steel heat exchangers, not aluminum".

(The simple reason on this point is that aluminum materials in heating systems require water treatment to keep the pH in a certain range higher than 8.0 whereas the combustion side is often quite acidic and hostile. If the water side is so tender, why not the combustion side? I need convincing.)

Is your husband a licensed installer or at least knows what he is doing? Sorry, have to ask.

As for the indirect, so many choices. The HTP SuperStor Ultra is a good value. Triangle-Tube has a tank-within-a-tank design that has a low pressure drop and proportional heat exchanger surface (area follows the size, more tank, more area). Look for 316L stainless steel construction, all welded, 150 PSI construction and NSF certification and at least 2 inches of foam insulation. Many good brands out there.

Eileen Olive

Other options?

Other than the Ultra-80, Knight or Contender, what other options migh there be? And willl today's mod/con boilers function well in a house using large cast iron rads and the large diameter piping that generally circles the basement to supply and return the hot water feeding these beasts? Once figuring the Heat Loss Calc for the house, how does adding an indirect hot water heater affect the needed BTUs?

Brad White

My order of preference:

Viessmann Vitodens 200 (size 6-24 in your case, the smallest). In a class by itself.


Viessmann Vitodens 100 (similar to the 200 in quality but fewer features- it was engineered to a competitive price-point. Same heat exchanger, different burner than the 200.

Triangle-Tube Prestige Solo (110 MBH may be a tad large but can turn down to 30 MBH input). Simple design, seems to be a good value.

Lochinvar Knight.

Any of these work well with cast iron radiators, splendidly so. Put TRV's on all of the radiators, good outdoor reset and you are off to the races.

If your piping running around the basement is iron too, it can be in the same zone but probably should be zoned differently for economy. If copper fin-tube, that would be in it's own zone as a default. With iron in the system though, I would install a return strainer at a minimum and insert some Neodymium rare earth magnets into the basket to catch stray iron particles. A Neptune filter is my own practice but costs more. Iron loves to nuzzle up to stainless steel; I think it has a crush or something.

As for domestic hot water, general practice says that if your domestic hot water needs are within range of "normal" (2-4 people, normal bathing, laundry needs, not running a car wash or commercial laundry and no hot tub), generally you would not add anything for domestic capacity.

One idea/rationale is that if you set back your heat at night, the tank warms up first then warms up the house. Remember, this only matters on the very coldest day and every warmer day you have more surplus. Resist the urge to over-size. Chances are the available increments have some "fat" by default anyway.

Keep in mind that most indirect DHW heaters and boiler setups take 100% of boiler capacity (often three times a conventional 40-gallon heater's worth) and heats that tank rapidly during which time your cast iron radiators keep glowing softly. You would never know the boiler was distracted.


Such a deal.

Eileen Olive

Thank you

In my case, with 2" steel supply and return circleing the basement, not to mention the large ci rads, I like the Neptune filter idea. Though I've never really heard of it before. What is the expected life-span of these mod/con boilers? I have heard they generally "last" for 10 to 15 years. Some friends have suggested I simply go for a fixed-fire Weil Mclain of 83 or 84% efficiency, because it should out live the newer mod/cons. My wife is pretty much set on the newer, smaller, quieter more efficient boiler. Me too. But I am trying to find the best boiler for the best price . . . wishful thinking, perhaps.

Eileen Olive

Heat and Hot Water

If we go with a Knight-80, what might be our best option for a long-lasting indirect tank?

Dean Rutledge

Condensing Modulating Boiler

If you are adding a condensing/modulating high efficiency boiler to a system designed for 180 degree supply 160 degree return water temperatures than you will only be running your boiler at about 86-88% efficiency.

All the boilers you mentioned are only efficient with return temperatures of about 120 degrees.

ALH_4

Balance

In my opinion, the best boiler at the best price is the Triangle Tube Prestige. It combines low head loss (translates to less electricity) with high effiency at a relatively low cost.

Ross_7

Mod/ Con load match modulation

One of things that people who knock the efficiency levels of mod/con boilers overlook is the load match modulation aspect of the mod/con boiler formula. Sure, not every application will have 80-120F return for the ultimate "condensing" efficiency, but even in high temperature return water applications the burner & fan will
"modulate" according to supply & return water temps, based on set parameters, also with the input of outdoor rest. Therefore, only burning as much gas as necessary to heat the water. A lot of people seem to forget this advantage when installing a new mod/con boiler.

ALH_4

Agree Completely

Ross is exactly right. As shown in this diagram from Viessmann, high efficiency can be achieved at high temperatures and low burner modulation.

Also, I think matching a Lochinvar water heater to the Lochinvar boiler is a good idea. They have a large coil with good heat transfer surface area. If you would like a stainless steel water heater, I think the Crown Megastor indirects are a good value. Incidentally, the Lochinvar indirects are re-branded Bradford Whites.

Brad White

Not entirely true

"All the boilers you mentioned are only efficient with return temperatures of about 120 degrees."

I think by this you mean "condensing efficiency". The term "efficiency" just needed some definition. As you noted though, 86-88% efficiency is not too shabby!

As practical matter, with proper outdoor reset and in temperate climates (say zero to single-digit winter design temperatures), there are sufficient numbers of hours where the outdoor temperature requires boiler temperatures within the condensing range to make it all worth-while. Those hours at 180 degrees are barely half of one percent of annual hours, call them one percent of winter hours.

Here in Boston for example, our design outdoor temperature is 7 degrees but our winter average is in the high 30's. That equates to about a 130 degree water supply temperature at a 1.6 heating curve (180 at say 5 degrees outside).

It is not just the absolute fixed points of operation but how many hours of operation at various temperatures which tells the real story.

Agreed, ideally, it is good to size your radiation for condensing at any hour of operation where you have design control. (I use a 140 degree design water supply temperature for example, and a 40 degree temperature drop.)

But this should not deter anyone from hooking up a ModCon to a system designed for 180 F. water, provided that the boiler can provide that 180 F. The Brookhaven National Labs (BNL) Study by Dr. Butcher, pretty much illustrated this approach as valid and economically viable.

An assessment of radiation to actual heat loss, especially in an older home which has since been insulated and sealed, may well allow full condensing operation.

john_83

Go with your first choice Weil utlra installed plenty of them with no problems to date. Plus the tech support is the best ive seen in the business, Also pricing on most modcons is pretty comparable

hot_rod

I think the Lochinvar indirects

are made by the same folks that build the Crown mega stor. I've heard also Crown may be shopping for a new supplier?? Possibly the Vaughn tank??

I like the Heat Flo concept of using a dual coil indirect tank. Piped so the second coil extracts even more heat and returns it to the mod con at a lower temperature.

Plus the ability to have double the surface area for quick recovery and maximun heat transfer.

hot rod

hot rod

Eileen Olive

EnergyStar

I have been told that this particular boier is not EnergyStar rated, I guess because of its efficiency rating. And my husband says it sells for about $1000 more than the Utra-80 or Trinity boilers. Can I presume it is that much better of a product? He likes the stainless steel heat exchanger more than the aluminum.

ALH_4

Squire

Oops, I was thinking of the Lochinvar Energy Saver glass-lined indirects, which appear to be B/W Powerstor's. It's hard to keep up with it all. Substitute Lochinvar Squire for Crown Megastor in my post above. ;-) Thanks

Eileen Olive

Over-sized rads

Can I possibly infer this to mean, that if the house is presently over-radiated (ci rads overly large for the area to be heated) and insulated, that a newly installed mod/con might perform better than expected in a system originally designed for 180* water?

Brad White

Exactly right.

Take an older house, originally uninsulated, with cast iron radiators sized for 180 degree water. Say the house had an original design heat loss of, oh, say, 85,000 BTUH with radiation to match. Say that was 567 SF EDR or so.

Over time the house was insulated, someone closed the darn windows once the Great Influenza passed, windows were replaced, gaps caulked and foamed. Now the heat loss is in the range of 42,000. You have double the radiation. It will emit the required heat loss at much lower water temperatures on the coldest day of the year. With outdoor reset, even more savings can be achieved.

Consider the largest radiators you could get- your floors. Radiant floor use such low water temperatures for the same reason. What you lack in temperature you make up for in area. You win!

Brad White

Energy Star

At 93% AFUE, the Triangle Tube indeed carries the Energy Star label and is rebate eligible.

http://www.triangletube.com/CondensingBoilers/PrestigeOverview.htm


Not the federal 95% minimum threshold (yet) but a respectable boiler. I cannot speak to pricing directly but I have found it no where near as wide a range from the other brands you mentioned.

I am with your husband on stainless steel over aluminum until convinced otherwise.

Most decent ModCon boilers with similar features tend to fall into a fairly close range. You do get what you pay for. Viessmann has superior materials and design, others have excellent materials, different grades of controls and other features.

There is a competitive market, do not shop just on price but on value and that means support and service.

Eileen Olive

Over radiation

The thought of too much radiation being a GOOD thing seems difficult to follow. If the house has larger rads than it actually needs, having been tightened-up over the years, then how can running "cooler" supply tems be helpful?

Brad White

Radiation is good

More radiation, it follows, must be better

Lower temperatures cost less to create. With condensing boilers, the least of all boilers.

I mean, so long as they do not take up essential living space of course! If the radiators served in the old days, they serve even better today.

The lower temperature dictum is founded in the fact that it costs less to heat water to lower temperatures, especially with condensing appliances and even more with outdoor reset. Lower cost and greater comfort is hard to beat.

Imagine running 180 degree water year-round and intermittent circulation. Too many systems ran and even today run this way.

Take a mild day in the 40's: Thermostat calls, circulator starts, boiler fires to a fixed limit, thermostat satisfies, circulator stops and the boiler burner stops when it regains it's artificially high setpoint.

The space sees a burst of heat, probably overshooting the setpoint. If you were to graph room temperature with this, you would see mountains and valleys above and below the setpoint. "On average" you are near the setpoint but could be one to five degrees above or below depending on your anticipator, distribution and thermostat accuracy. A cycle of heat like this would occur less frequently than in cold weather. You may also get a "scorched" smell, at least initially early in the season.

In colder weather, the cycles will happen more frequently and may even out a bit. Heck, by that time, the water temperature and the heating needs are as close as they will get to aligning. Yet, they may still be too high- 180 versus what may only need to be 140, right?

Enter outdoor reset (with or without modulating condensing). Now your water temperature is indexed and continually adjusted to your outdoor temperature.

You should accept that the heat loss is directly related to the difference between indoor and outdoor temperature. You should also accept that the output of a radiator is directly related to the average water temperature within it (surface temperature really) and the room temperature. This relationship is key to matching input to output, balancing immediate heating energy expended to the heat losses at that time.

This operation, using constant circulation and when room temperature is graphed, will show nearly flat or very slightly undulating long waves, not the spikes of on-off, high-temperature control.

Does that make sense?

Take the other extreme: Too little radiator. Your only choice short of moving to a warmer climate is to use higher temperatures. If you had half the radiation you needed, you would have to run water at, say, 260 degrees F.

I will have to study what the specific fuel content of burning money is, but I think you get the idea now.

Uni R_2

I have a strong Prestige bias...

Eileen, I spent far too long searching for a replacement boiler, especially now knowing just how much savings are there. I had dismissed the Prestige right off the bat for a couple of years because it doesn't modulate as low as others and the efficiency rating wasn't the best either. After getting quotes for the Ultra and Vitodens, I was in a major dilemma because neither seemed to ring my bell completely. I liked the Vito's looks, burner and heat exchanger, but much preferred the more basic controller on the Ultra and its lower modulation range.

While still undecided, I did a last scan and ended up realizing that the Prestige really had no weaknesses for what I wanted it for. I tried to find where people had any issues with one and couldn't (saw the first one the other week and it was a fan I think). I looked at the parent ACV site and saw that the same boiler in Europe gets straight 'A's on the SEDBUK efficiency rating system and does as well as anything there.

I ended up having one installed mid-December of last year by a Triangle-Tube recommended installer and was amazed at how little gas I consumed - 1300 cubic meters of NG which cost a whopping $650, despite the house (2400 sqft near Toronto) actually being a few degrees warmer than in the past (we spent well over $2K in oil traditionally). I was also amazed at how little electricity it used. On standby, it uses 14 watts (for the controller), and when heating it uses 100 watts which includes the built-in circulator. I seriously doubt that any other boiler on the market could save any more money than this one does and mine is way oversized for my heatloss to boot.

Weezbo

Eileen, depending upon your current lifestyle,

the fixture unit load in your home and how seriously you take the efficiency of your Hot water requirement...meaning what you are willing to do to regulate $ flow out the drain...you might want to consider a SmartIII mini, Instantaneous water maker from Triangle Tube in conjunction with your modulating condensing boiler or high efficiency heat source...

ALH_4

Prestige

Is the Prestige the Model T of boilers?

[Deleted User]

Mod/Con boiler efficiency

[Deleted User]

Mod/Con boiler efficiency

Old radiators were not sized for 180F supply water. 160F was more common. Even with heat loads exceeding 75btu's per square foot, old column style radiators were often oversized for "open window" operation for fear of the deadly TB, more commonly known as 'consumption'.

This makes nearly all surviving cast iron radiators oversized. With this high-mass, low-temperature load, all low-mass Mod/Con boilers will outperform all atmospheric high-mass cast iron boilers if properly sized and applied. This bold statement applies to comfort AND fuel consumption!

AFUE is a poor and often misleading indicator of true operating costs. With modulation and outdoor reset, design conditions will rarely occur and the boiler will be operating at water temperatures of 130F and below most of a heating season.

As for indirects, since their standby losses are only a few degrees a day and they last at least twice as long as a conventional water heater, any one will do. I should say also that every Tom, **** and Harry will not find the indirect at his Big Box which makes it a natural for all professional HVAC people and their plumbing cousins.

Matching boiler to tank by manufacturer is not as important to me as matching demand to tank size.

As for DIY Mod/Cons, I have witnessed countless condensing boiler installations, which can only be described as self-inflicted disasters perpetrated by misinformed professionals. Were I still manufacturing boilers, I would recommend my competitor's boilers to all DIY customers.

MA

[Deleted User]

Mod/Con boiler efficiency

Old radiators were not sized for 180F supply water. 160F was more common. Even with heat loads exceeding 75btu's per square foot, old column style radiators were often oversized for "open window" operation for fear of the deadly TB, more commonly known as 'consumption'.

This makes nearly all surviving cast iron radiators oversized. With this high-mass, low-temperature load, all low-mass Mod/Con boilers will outperform all atmospheric high-mass cast iron boilers if properly sized and applied. This bold statement applies to comfort AND fuel consumption!

AFUE is a poor and often misleading indicator of true operating costs. With modulation and outdoor reset, design conditions will rarely occur and the boiler will be operating at water temperatures of 130F and below most of a heating season.

As for indirects, since their standby losses are only a few degrees a day and they last at least twice as long as a conventional water heater, any one will do. I should say also that every Tom, **** and Harry will not find the indirect at his Big Box which makes it a natural for all professional HVAC people and their plumbing cousins.

Matching boiler to tank by manufacturer is not as important to me as matching demand to tank size.

As for DIY Mod/Cons, I have witnessed countless condensing boiler installations, which can only be described as self-inflicted disasters perpetrated by misinformed professionals. Were I still manufacturing boilers, I would recommend my competitor's boilers to all DIY customers.

MA

[Deleted User]

Mod/Con boiler efficiency

Old radiators were not sized for 180F supply water. 160F was more common. Even with heat loads exceeding 75btu's per square foot, old column style radiators were often oversized for "open window" operation for fear of the deadly TB, more commonly known as 'consumption'.

This makes nearly all surviving cast iron radiators oversized. With this high-mass, low-temperature load, all low-mass Mod/Con boilers will outperform all atmospheric high-mass cast iron boilers if properly sized and applied. This bold statement applies to comfort AND fuel consumption!

AFUE is a poor and often misleading indicator of true operating costs. With modulation and outdoor reset, design conditions will rarely occur and the boiler will be operating at water temperatures of 130F and below most of a heating season.

As for indirects, since their standby losses are only a few degrees a day and they last at least twice as long as a conventional water heater, any one will do. I should say also that every Tom, **** and Harry will not find the indirect at his Big Box which makes it a natural for all professional HVAC people and their plumbing cousins.

Matching boiler to tank by manufacturer is not as important to me as matching demand to tank size.

As for DIY Mod/Cons, I have witnessed countless condensing boiler installations, which can only be described as self-inflicted disasters perpetrated by misinformed professionals. Were I still manufacturing boilers, I would recommend my competitor's boilers to all DIY customers.

MA

[Deleted User]

Mod/Con boiler efficiency

Old radiators were not sized for 180F supply water. 160F was more common. Even with heat loads exceeding 75btu's per square foot, old column style radiators were often oversized for "open window" operation for fear of the deadly TB, more commonly known as 'consumption'.

This makes nearly all surviving cast iron radiators oversized. With this high-mass, low-temperature load, all low-mass Mod/Con boilers will outperform all atmospheric high-mass cast iron boilers if properly sized and applied. This bold statement applies to comfort AND fuel consumption!

AFUE is a poor and often misleading indicator of true operating costs. With modulation and outdoor reset, design conditions will rarely occur and the boiler will be operating at water temperatures of 130F and below most of a heating season.

As for indirects, since their standby losses are only a few degrees a day and they last at least twice as long as a conventional water heater, any one will do. I should say also that every Tom, **** and Harry will not find the indirect at his Big Box which makes it a natural for all professional HVAC people and their plumbing cousins.

Matching boiler to tank by manufacturer is not as important to me as matching demand to tank size.

As for DIY Mod/Cons, I have witnessed countless condensing boiler installations, which can only be described as self-inflicted disasters perpetrated by misinformed professionals. Were I still manufacturing boilers, I would recommend my competitor's boilers to all DIY customers.

MA