Boiler Choice Quandry: Installer Experience V.S. Boiler Design.

mik

I'm a homeowner looking for the best oil boiler to match my heat loss of about 91,302 Btuh.  My contractor has offered the following:

Weil-McLain Ultra Oil

Weil Mclain WGO Series3

Slant / Fin Intrepid

And after my inquiring about it, the Slant / Fin Eutectic.

The installers have experience only with the Intrepid and the WGO3 and the W-M Ultra Gas (we plan to stick with oil).  Should I take a chance and ask them to install one of the 3-Pass boilers they have no experience with or should I choose one of the Pin-type boilers which they've installed before? Is the W-Mc Ultra Oil similar to the Ultra Gas?  Are the Ultra Oil and the Eutectic equally reliable boilers? All responses are welcome.

icesailor

Boiler choices.

They are all good boilers. I haven't heard raves about W/M Ultra Oil. I find W?M WGO's to be bomb proof and easy to clean and service. I have one in my own home and have installed quite a few WGO/WTGO's.

Ironman

A Good Installer...

Should be able to install almost any boiler correctly if he follows the instructions and particularly the burner set up portion. I'm very partial to Buderus' 3 pass when it comes to oil. I wouldn't consider a pin boiler. The Buderus cast iron is actually flexible and can withstand thermal shock that others can't. When coupled with their "Logamatic" control which provides outdoor reset, the fuel savings can be greater because the reset curve can be set lower. The installer might need some help if he's never done a Logamatic. The 3 pass is also much easier to clean.

Just my preference. I'm sure others have theirs. If you really like your installer, talk to him and see what he's comfortable doing. Also, will he be the one servicing it?

mik

Is a bypass / primary / secondary piping required for the Eutectic or Ultra Oil

According to the manjfacturer the Eutectic also has a flexible C.I. heat exchanger, but I don't know if it can withstand thermal shock.  Do the Eutectic and the Ultra Oil require a bypass / primary / secondary piping?  I was hoping to keep things simple for the installers. 

Big Ed_4

Three Pass Boiler

I prefer a three pass boiler , positive pressure with push nipple construction boiler ...For comfort and fuel savings a out door reset would be a nice addiction ... The three pass tend to be longer so if you have the room , it would be a better boiler choice ... I am sure your installer can handle the install .. Like any new boiler he should read the online manual before installing.. Matter of fact I just did the same for a gas condensing boiler which this brand is new to me ... I like to build the system for the space in my mind first , days before , and pick up the parts needed before hand so the install runs smooth ... That is my theory any way



No, a three pass is not difficult install .. Just a little different in piping then a pin style , Piping and venting tend to come out one of the sides rather then the top .. The boiler if stated in the manual has to be pitch up to the supply .. Some don't have a built in air scoop which need to be added to the near boiler piping .. Some boiler like the Buderus have a trans type thread supplied nipples converting from European to american thread types .. This is where reading before hand is recommended ...

Ironman

Bypass / Primary / Secondary Piping

1. Depends on the boiler. Can it take low temp. return water? How much head loss thru the boiler?



2. Depends on system piping, pump(s) and controls. You have to maintain a certain delta T thru the boiler, usually 20-30deg. Multiple pumps whith large pipes might push water thru the boiler too fast.



 There is no certain answer without knowing all the variables on the job. There may also be more than one approach.

Brad White

FWIW

Our office standard is to specify, if available, 3-pass eutectic cast iron boilers, when we specify CI at all.



(We do a fair amount of public schools and that is a traditional institutional standard. Sometimes only oil is available, no gas, or there are septic issues that preclude the use of condensing boilers, in case you were wondering.)  That there are at least three manufacturers is a key factor in our choice, due to public bidding laws. So DeDietrich, Viessmann, Buderus and Burnham MPC are the names we often specify. If any ARRA work, ok, we cannot always specify domestically made and admit defeat on that point, but that is the spread we see.  Of course, we are talking about boilers in the 50-100 BHP range here, not residential, but the principles are the same.



What we like are the higher efficiencies, always over 85% on paper and 87% is our target, again, on paper. But better than single-pass.  They are also easier to clean, from the business end.



The debate over "no low limit to entering water temperature" ebbs and flows. We stick with the physics that we do not want condensation primarily and boiler shock, being less frequent, a close second. 



We often see recommendations allowing down to 122F return water, one says to 105F. IIRC. The manufacturers all tend to rely on an internal circulation pattern which passes some of the primary HW back to the return and around the outside to promote more even temperatures (less thermal stress) and possibly to "cheat" the return temperature effect.  This has to affect efficiency, but we also presume it is taken into account in the ratings as it cannot be "switched off".



Regardless, we do not push these low temperature limits and still opt for return water protection with a bypass valve or circulator.



Incidentally, the term "eutectic" has a certain cache', but all it means is that two or more metals are blended into an alloy that has a lower melting point than the components alone. We particularly like the DeDietrich metallurgy. The company is actually French, located in the Alsace region and despite the German name. Their iron made very good tank turrets. Not that it helped much, but it impressed Guderian's Panzer Division for a few days.

Bob Bona_4

yer killing me Brad

I love how your posts are multi leveled founts of info.

NRT_Rob

for oil

I think two boilers hit a level that leave most others behind, significantly. Viessmann Vitola, and Energy Kinetics System 2000.



But good luck finding guys used to them.



I would ask the installer what his comfort level is with the unknown equipment, and be sure he's going to stand by it as he would anything. Our standard advice is to pick installers before equipment.... no equipment is good if it isn't installed well, and a good installer will let you know when you're out of his comfort range.



A lot of them like to learn as well, and so as long as they are willing to make an extra visit or two to dial in a new source if it's a bit different than what they are used to, great.



You don't want anyone "installing angry" though.

ChasMan

Slant Fin

I have the little slant fin EC-13A with the older Thermatic control panel and Riello burner. I have had a lot of difficulty getting it to start smoothly although I admit, I have not tried that much tweaking. One of the reasons I went with it is because it is smaller than the other makes and I have limited room. I have only had it for two winters so can't comment on the long term viability of the casting. I run it cold start and while the baffles are turning yellow / red, the exchanger itself has a nice clean black patina on it. No signs of rust or anything. The design looks good on paper. The condensate tends to get blown out. This casting is the same one sold in Europe as a condenser with a different burner. One thing that troubles me is the burner setups that Slant-Fin provides are completely different than the ones DeDietrich provides and Slant-Fin has provided no explanation of this. In fact, the airgate setting in the manual is so far from any other make that I can not beleive it is correct. The venting instructions for the DeDietrich are also very different.The boiler soots like crazy at the factory setting. This boiler doesn't have the Becket NX approved either so I would tend to look elsewhere IMHO, nothing agianst Slant Fin, I just think this could be better executed.

CMadatMe

Chimmney

One thing I did not read in any of the posts was venting and making sure that chimmney is inspected. One issue I've seen many times when replacing pin-style boilers with 3-pass is flue condensation due to the low stack temps especially when adding ODR to the boiler. You may find that chimmney may need to be lined. Just something that the contractor should be inspecting and looking at when providing a quote.

mik

Anyone install a Weil-McLain Ultra Oil?

I just checked with the installers and they will be installing a bypass valve, good to know.  Thanks Big Ed for contrasting the two boiler designs from an install perspective and thanks Rob for your tips on installer psychology and last but not least Brad W.  ChasMan, thanks for the info about Slant / Fin's aberrant burner setups, I was leaning toward the EC-13, but now I just don't know.  How does the W-Mc Ultra Oil stack up?  I don't hear much about it.  I've learned that it weighs about 600lbs.  We do have the room for it.

Steve Ebels_3

Best residential oil boiler?

Viessmann Vitola with their burner.

Set it up right change the nozzle and filter once a year and forget it. The Vitola will outlast most of the people that own one. Including myself.

We have a 300Kbtu model running in a dairy barn of all places that works hard every day, not just in the winter. It runs flawlessly day in and day out to the tune of approx  6,500 hours of run time per year and 20,000 burner cycles. It just doesn't quit.

Efficiency test show between 86.5 to 88% depending on water temp. It runs all the heat and hot water in the barn including about 2,100 sq ft of radiant floor. Water coming back at 55-60* doesn't phase it. Don't know of any other oil boiler that will withstand that use.

Color me orange..........Where's Ken Secor when you need him.........:)