efficiency reality

Supply House Rick

mod con boilers using Giannoni heat exchanges

Do you have any pictures you can post of boilers opened for service.

I'll attach a few of mine for comparison.

My thanks to anyone else reading this who could post some photos with approximate run times.

Thanks, Ken

Unknown

WOW!!

What happened to them? I have not had any look like that. Like to hear the story.

Supply House Rick

Supply House Rick

WOW

Follow this link:
http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=62318&mc=43#Message436267

Any photos?

Ken

Unknown

never had to.

I never had a HX look like that or I would have lots of pictures.

k_2

re Perry

That is a really good explanation, but you seem to contradict yourself, or maybe i am just blurring things together. You say that many mod cons are more efficient at low fire, but that underfiring is generally less efficient.

I wonder if on these mod cons the full firing would be considered overfired on a boiler with 'dumb' controls


It also shows the importance of a boiler being sized appropriately, and that I am probably right in being frustrated with boilers being either too large or too small

Would it not make sense tho to make a boiler most efficient at its highest firing rate? I guess they must assume it does not fire there that often. Again, back to sizing.

k

jp_2

darrell ?????

why heat water hotter than it has to be? a mod/com can heat to a temp needed to heat the house, cast iron boilers heat water up to its set point, most of the season this is hotter than needed. the hotter the water, the more energy needed to heat that water, and its not linear!!!!!

Darrell_7

In a perfect world, I agree completely. However, most upgrades from atmospheric cast iron boilers to mod/cons are being done with minimal changes to the near boiler piping and none to the house piping or delivery system. These upgraded boilers are being sold, or mandated, on the premise that they are vastly more efficient, more "green", and will save the customer tons of money. I often hear that the upgrade will pay for itself in a year or two at the most. My original question seeks to investigate the reality of these statements because the reality that I see, as a serviceman, is that these "crude" upgrades, for lack of a nicer term, are not significantly more efficient, often are not as comfortable for the customer, cost a great deal more to maintain and will not last as long.

They are not significantly more efficient because the delivery system has a very narrow parameter in which it can be effective at heating a space, thereby limiting the parameter that the boiler can work in and, for the most part, unable to take advantage of the condensing mode which significantly drops the posted efficiency in some cases back to the 85% percent range, which can be easily attained by a cast iron boiler that will give the customer the comfort they expect without any change to the delicery system and a much longer service life.

They are not as comfortable for the customer because the delivery system is designed for an entirely different theory of heating a space and won't work well with a mod/con in most cases. True enough, some systems work just fine without piping or delivery changes, but I see many systems that do not, requiring me to change to parameters that the mod/con works within effectively making it into a very expensive and high maintenance 85%boiler.

The service cycle on the mod/con boilers seems to be settling into the six month range wheras a cast iron boiler can go for a year easy or two without being seen by a serviceman for cleaning and maintenance. All cast iron boiler manufactures that I know of recommend that their boilers be serviced annually by a licensed, competent, heating professional. The mod/cons do not enjoy that once a year look see and if it is neglected go bad really fast...see the other post.

Nobody is arguing with the other posters here that are saying that the ss mod/cons that are available to most consumers are only going to last 5-10 years. That is a tough sell and at the least should be dealt with honestly with a prospective customer. The cast iron boiler will be in the basement until they get tired of it or talked out of it.

The comparison to vehicles is not a good one because nobody has required me, or helped me to pay for, a higher efficiency vehicle. The Government did require higher standards for emmissions to apparently good effect but I can still choose for the lineup to suit my needs. In the case of boilers the government is mandating the upgrade at the customer level and granting money for the upgrade. It appears that the upgrade equipment is not really ready for the market place, or is sub-standard, and that an informed customer, without the bait of a grant or the pressure of a mandate, would likely choose a supposedly less efficeint appliance that will last longer and cost less to maintain.

Having said all that, if a contractor can be involved in a new home from the blueprints up designing the heating system for full utilization of a mod/cons capabilities, creature comfort and ease of maintenance, then by all means do so with the full, and realizable, expectation of fuel savings over a cast iron boiler...but be honest about the service cycle and the service life of the boiler. And be realistic about the operational costs and expected fuel savings.

Reading the other posts that this one, and Perry's, seem to have spawned would lead one to conclude that on an EXISTING system, where upgrades to the delivery system is unwanted, not practical or cannot be done for budget reasons, the customers money is better spent by applying good and developed technology to the exoisting boiler. Some of these ideas are ODR, (admittedly limited but very effective), regular cleaning and maintenance, changes to the near boiler piping and zoning, changing the water heater to an indirect, (probably the single most efficient and realizable payback), maybe some two stage gas valves if the manufacture approves, modulating circ pumps, smart zone valves, and on and on. Any of these can be done to existing systems without major expense, can be staged as budget allows, and will produce real world savings without compromising system service life or service cycle. They do take more knowledge and expertise on the part of the contractor.

As far as using outdated thinking...my teenager says that I am "superannuated" so I s'pose it could be true. However, I have two calls this afternoon that are to brand now mod/con boilers, less than six months old, installed under the rebate program with no changes to the near boiler piping other than looping it together to make it primary/secondary, and no changes to the delivery system. Both customers complain of being cold, and the boiler running all the time. So, maybe my thinking is as modern as this afternoon...I will have to change the paramenters of the mod/con so that it will deliver hotter water to the baseboard, knowing that this will limit the condensing mode to the shoulder season. And then I will take the time to explain to these customerrs why their brand new, ultra-high efficient boilers are not saving them any money. I will also take the time to explain to them how they can remodel their homes to take full advantage of thier new boiler...and then they will get mad because that was not explained to them by the installer...who won't come back to awswer their questions or service the boiler.

Too long? Shoot me with Perry! (I enjoy Perry's posts and learn much from him and the other experts that chime in here).

jp_2

well

I've reread your first post. I don't see much in talking about efficiency of poor installations.

i stand by my couple of straight forward answers.

by the way if a single parts fails do you always replace the entire unit? these are not hi tech devices, this technology has been around for a long long time.

Tony_23

My thoughts

I set up mod/cons on retrofit jobs all the time w/o changing emitters or adding to them. 110-120 low end supply temps on bbd keeps everybody happy. Since they are mostly counterflow, the return temps and exhaust temps run real close to the same. I have many that condense when supplying 160 water, as the return is below condensing temp.

The thing is, a mod/con that's not condensing is still using less fuel than a CI boiler with fixed input. Modulation is the bigger factor. Standby losses also are much less.

I've even got some that operate on fixed setpoint instead of ODR because the requirements changed and deep setback is now used, making ODR a hindrance. They still save 30% or more.

I also don't see them all at 6 month intervals. Once a year is plenty.

Proper piping and flow is paramount to proper operation, just as important as proper flame set up.

Darrell_7

Thankyou, I appreciate your real world input! I am not opposed to mod/cons in any way...some of the offline emails seem to think so...but, I'm worried about the life span. What brand do you use and what issues do you encounter? If you'd rather not air that here my email is dhci at live dot com

Tony_23

I've used

I've used three. W-M Ultra, TT Prestige, and Baxi.

The Ultra is more able to be tweaked and Aluminum heat transfer is very quick. Real thick. If they're set up right on install they aren't seeming to lose much "meat".

The TT is a nice, low head design. Lots of parameters are blocked out at the factory. I believe its an attempt to idiot proof their machine for longetivity MUST be wall mounted. I've had to build "walls" to mount them to, as we are in old stone foundation country.

The Baxi's okay. I hate their gaskets that leak, no matter what you do to them or how tight you go. Their X-tanks are usually flat and the float vent in the circ always leaks making a mess and causing a low water event.