High temp rads with condensing boiler?

Floyd

You will find that if you have your system designed for the worst case, much of the time you won't even be close to that....There will be much of the time that you will just need to take the chill off and that is where the condenser will really shine. Also you may find that your retrun water temps. may be low enough to keep things condending way more than you think. I have personally had the Ultra condensing at well over the so called line of 140*.....
Also, there's no better place "to play" than at home....I hav sat for hours watching the 'puter track my Ultra....I have also played with mine at home before going and trying things in the field.... see if it works at home first.....
Go for it.... it will pay you back many times over with knowledge and experience....

Floyd

Rocky_2

Please enlighten a poor oil burning non-condensing tech...

Natural gas being installed on my block this summer. Currently have a Burnham V-18 oil boiler. Was gonna swap it out this summer for a Buderus 215-6 or something close. However, having natural gas on the block certainly changes the mix. Have all baseboard and unit heaters. Do have an indirect for hot water. Does it make sense to use condensing bioler in my system when it will be out of condesing range for probably 98% of time? I know on start-up from a cold start it will condense until internal temps reach non-condensing range, but with our degree days and design temps here, (13,500 and -45 respectively), we will NEVER be heating with water under 135 or so. What is the real scoop from those of you in the know? Natural gas is fairly new here to Fairbanks and so I am pretty unfamiliar with gas equipment. I will defer to those of you who work with it on a daily basis. Was originally going to go with the Buderus oil with Riello burner and tekmar 260. What would you all suggest now? Would really LOVE to try the Buderus wall hung condenser or the Weil Ultra condenser, just don't know if they are worth the extra moo-lah and shortened life span. Thanks in advance to all the gas guru's out there!
Warm regards from (not so) chilly Fairbanks
Rocky

Al Letellier

condensing boilers

Rocky, we don't design for your kind of temps here in Maine (7500 DD's and -20), so we don't have the experience for your climate, but think about this....how much of your heating system is above design? If I were going gas, I'd buy the most efficient boiler I could find, regardless of how much or how little condensing it would do. Unless the manufacturer has a problem with too little run time in the condensing mode, I'd go for it.
How'w the weather there in July? A bunch of us from NAOHSM are taking a cruise up there next summer and a land trip into Denali....can't wait...have been wanting to go there all my life....but you can keep those 13K degree days....
Good luck.

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Ken_8

Both the posters above are

correct!

The only time your system comes close to being "out of thermal range for high condensing operation" is on the few days a year when the outdoor temps are at the extreme low of the entire year; and even then, some condensing will occur; especially when firing the indirect!

Think about your cool fall and spring days.

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clammy

modulating burners

In the few jobs where i've used a condensing boiler with baseboard the HO have cut there gas bills just about in half and there old boiler where not to oversized .The beauty is if you have a few zones the burner will modulate down and even if it is not condening it is at least not short cycling which in my opion reduces gas comsumpition .I think in the near future there will be more and more of theses types of boiler installed like everything it just takes a while for everybody to get used to .Before next winter my boiler is getting replaced and most likly a htp munchkin with a new indirect will be in place .I firmly believe that with mirco zones it's the way to a better system and fuel savings .Ps with a outdoor reset and constance cicrulation also helps that supply water temp .Peace and good luck clammy

Andrew Hagen (ALH)

Modulation

I still maintain that the condensation is not the primary benefit of the Munchkin, Ultra, Vitodens, and others. Burner modulation is the primary benefit. You can fire much more closely to what you need on a constantly varying basis. My primary experience is with the Vitodens where the 167F high limit is something of which to be aware.

-Andrew

Mad Dog_2

There's also a reason why baseboard charts

have charts that show different btu outputs at different temps. As long as your existing heat units are sized big enough, you should benefit from condensing technology. Is it the perfect application for it? No, but you will still be ahead on fuel savings. Mad Dog

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Bob Sweet

Condensers with B.B.

I also have several condenserrs installed with B.B. and the customers are very pleased with the fuel savings they've seen. One in particular saw a savings of 50%. Like others have said, the 180* temps are required for those few times a year you'll need it ,the rest of the time you'll be surprized how well B.B. performs at much lower temps.( as long as your not under radiated)

jerry scharf_3

boiler condensing range

Rocky,

Like the others, I question the 98% comment. It's not the supply temps that count, it's the returns. If you set up the system for 30F delta T, you may be able to keep the return at/below 135 for a good part of the heating season. So if you run 170F water and 30F delta T, it would be about the same as 20F delta T and 165F supply water. How much of the time do you run the supply water at or below 165 for your system? If it's possible to add radiation, the return temps can be lowered and more heat squeezed out of the gas.

There is another major advantage to the modern gas boilers. The penalties from starting and stopping the boiler is very small, and the number of on/off cycles goes way down. The only startup penalty I can see is that there is a few seconds of time that it takes the radiant component of the burner to come up.

Now one interesting thing will happen. I would assume the gas pipes are below the permafrost, so the gas may come in near 32F. If the outside air is -45, the fuel/air ratio will be a bit leaner than at +40. This should indicate that you should run the units at the rich side of the manufacturer's specs, knowing that it will lean out in cold times.

With the amount of fuel you guys must burn, even a 20% saving over the year has to amount to a good chunk of money.

jerry

Rocky_2

Cool! Looks like its condenser-ville for me!

This discussion pertains to my shop. Bought it in August of last year in a foreclosureso I have only one winter's worth of history for it. Bear in mind that things are a little different here. We don't just hit design temp once every two years for a day or so. We hit design temp several times a year for often weeks at a time. When that Siberian High Pressure comes in and squats on you like a 500 pound gorilla for about three weeks at a time, WHOA PARDNER! But even if it is not design, our "normal weather" still is about -10 to -25 for much of the season. We should do a field trip for a bunch of you all in the middle of winter. C'mon up and play with me and Weezbo for about a week at -50. WE could show you LOTS of very cool stuff. Literally. If you wanted to run lower water temps here, the wall would literally have to be covered with baseboard. But,I'm gonna try it anyway. After all, I know a guy in the business in case it doesn't work! HA! This place has two apartments upstairs, each has one zone of baseboard. One is a three bedroom, two bath 2000 square foot apt, the other is a one bedroom, one bath 15oo square foot apt. They are freaking huge! My 3500 sq. foot shop/office is below. Baseboard in offices and unit heaters in the shop area. The tenants did not complain about it being cold up there last year, but then again, I had the Burnham V-18 set for 180-160 on the HOneywell R8182H. As stupid as it sounds, I haven't even done a heat loss on my own apartments yet! But I will, I PROMISE! I would like to add a little baseboard to the units just so I can run lower water temps and still heat properly at reduced temps. So, here is the 64,000 dollar question for all youse guys who have installed condensers: Recommendations? Weil Ultra, Buderus, Vitodens, Munchkin, other? C'mon, C'mon, hurry up, I'm PSYCHED now that I get to go play with something new!
Thanks for all the great input as usual. By the by, it was 86 here in Bearflanks today. SMOKIN' HOT by Fairbanks' standards!
Warm regards,
Rocky

Rocky_2

Al, weather is great here in the summer

The interior of Alaska, which is where I'm at, has the largest temperature swings on earth. -65 in winter happens at least once every two years, and + 95 happens about once every two years as well. Most summer days here are high 70's to mid 80's. With those perfect temps, 24 hours of sun, and lots and lots of rivers, those poor fish don't stand a chance. Your cruise is going to take you to some absolutely magnificent scenery through the SouthEastern part of Alaska. Was in Icy Straits last summer with my dad fishing out of a little village called Hoohah (about 50 mile west of Juneau). Even for someone who has been all over the state Dall Sheep and Moose hunting, that was once of the most magnificent areas I have ever seen. Whales literally breaching so close to us while fishing that they were blowing their nasty old lung breath on us. I'VE BEEN SLIMED! Hope the weather holds for you as the Southeast can get a bit damp. Enjoy the ride.
Rocky

Andrew Hagen (ALH)

Temps

The Vitodens is the best on the market in my opinion. The only issue is that the Vitodens has an operating limit of 167F. If that design temp is ok and the budget allows you can not go wrong with a Vitodens boiler. The internal controls have an incredible number of functions right out of the box.

Unit heaters like hot water, and you want the noise of the fan to shut off as soon as possible. You may want to use the motorized mixing valve and the 2nd heating circuit to run the baseboard as cool as possible on circuit B and the unit heater as hot as possible on circuit A.

-Andrew

Weezbo

He he he *~/:)...You are a Master at this stuff Rocky

so trying to round up some help for 50 below freezups and service calls,... hey? Tricky I would like to say (add) though ,that, the severe cold makes one Think Quicker )

The other day i was running the pump block theory of control through the hydronic ethers with Lee,he is seriously considering ting in the baseboard through the taco block.....to me that in itself should accomplish a definite step in the right direction...going modulating condensing on the Shop sure sounds like a great idea, to me. from what i have gathered the boilers will still condense at relatively higher temps,...i think the thing to do though would be to step down the returns to an all time low vs a partial reset type stradgey...or direct return.sort of 4 way dummy mix the return down through constant circ on some in slab radiant ,and then give that return water a choise of returns to the boiler...as cold as it gets that really shouldnt be a real difficulty )) Oh Did the 24 : cresent thaw from the fingers of the last guy we were working with....:))

Floyd

It's all in the SUPPORT!!!!!

Hey we all know that if it can break it will at the worst possible time...... If ya ain't got the support to back you up when the sucker decides to chuck a fit then your basically screwed..... by the unit that has the best people behind it, the ones that your sure will not let you high and dry when you need them.
Me, I got that with the WM people.... I have a great distributor behind me, a great factory rep. that communicates great with me and will be there if I need him. Also I have had a great relationship with a few of the factory tech. guys.
The product has been extraordianry also.... the Ultra boilers have given no trouble that I haven't brought on myself because of my ignorance.....

Go with the people though, they will make any product much better if they are the people that are there for you....always.

Floyd

Weezbo

Er..I think what Floyd is trying to say is, put a small two

foot perimiter loop around the perimiter in some gypcrete and use it to get the return temps down *~/:) ...the slab underneath will pull plenty btu's and setting it on an i series valve to try to keep up all winter long should keep the boiler in condensing mode with no problem maybe i miss read what hes trying to say...i dunno

Steve Ebels_3

If you want the best

Vitodens would be the way to go. Nothing else like it and I'll dare wager that it will last longer than any other condenser on the market. The integrated control "thinks" like you want a condensing boiler to run, always trying to keep itself within optimum parameters for max efficiency. I can't say enough good about the support from Viessmann. I wish every company I dealt with held the same philosophy..........life would be good!

As far as the 167* limit goes, it's something you have to deal with on this particular boiler, BUT!, bear in mind that a limit of that temp virtually assures that the boiler will operate in condensing mode 90% of the time. Suggestion: add a constant circ loop with panel rads and TRV's. You won't believe the comfort.

Yes it's expensive. Yes it's different dealing with lower temps. If however, you want max efficiency, that's the beastie to go with.

The burner on the Vito will eliminate any problems you may have with super cold intake air and or sub zero gas. It takes care of itself. I'd buy the Vito just for the burner.

The response we get from most people when we hang one on the wall is, "THAT is going to heat my house!!?? And it always does.