Best indirect HW for Buderus GB142
After plenty of research, I'm installing a Buderus GB142/30 gas mod/con boiler in my house, replacing an ailing oil-fired boiler. I want to pair it with an indirect HW tank. My HVAC guy initially quoted a Buderus ST150 40-gallon indirect tank, but for roughly the same money he's willing to install a SuperStor Ultra SSU-45 45-gallon tank. His only concern is about connecting the DHW tank sensor from the Buderus boiler to the SuperStor tank.
The 5-gallon gain aside, I have some reservations about the Buderus ST150. While some of the quotes I received followed the "matching" principle of using the same company for both boiler and indirect tank, most quotes paired a boiler with a HTP SuperStor tank. I've seen numerous examples on the Internet of GB142 installations that are paired with SuperStor, not Buderus indirect tanks. The HVAC guy claims this is a result of most installers being more familar and comfortable with SuperStor.
I guess it comes down to the stainless steel vs. interior coating and anode rod debate. While Buderus' Thermoglaze coating is supposed to be the best, most of what I read indicates that stainless is much more preferred. Both have excellent heat loss ratings, with Buderus having a slight edge (1/4 degree F per hour vs. 1/2 degree F per hour for SuperStor). But the possibility of the Buderus coating failing worries me, and I'm bothered by the idea of that I may need to replace a magnesium anode rod at some point. I don't think my town water has a high PH level or contains a lot of chlorine, which I understand can corrode stainless steel. Also, I don't care about having mismatched equipment - I want good quality stuff that will last the longest. So I'm leaning towards the SuperStor.
Any suggestions which way I should go? How much more difficult is connecting a SuperStor to the Buderus boiler than connecting a Buderus ST150?
Not a pro but I agree with you, go with the SuperStor 45. Running that myself with a Buderus Oil boiler. No complaints....I trust stainless more than a special coating.
It's just a tank no difference to speak of when installing.
My HVAC guy wants $200 more for the HTP SuperStor tank, but I think I'll easily make back that money in reduced servicing fees and no anode rod replacement charges.
never seen either tank leak to through the skin. i have seen both fail from heating coil leaks. both are a good choice. if you are looking for money saved over time 1/4 deg sounds like a good bet but 5 extra gallons for the same price sounds good for a longer shower. a sensor doesn't care what tank it is attached to.
Thanks Referrob. So it sounds like the heating coils, not the tank liner, are the weak link (assuming the anode rod is serviced properly in the Buderus tank). Any thoughts on what could contribute to the coils failing, such as water quality?
I know the SuperStor tanks have a 2" layer of foam insulation around the tank and a plastic jacket. Would an insulating blanket/jacket around the tank make a real difference with the heat loss? I know they're great for electric and gas-fired tanks with less insulation and metal skins that radiant a lot of heat and are warm to the touch. But I don't know if an insulating jacket would trap the very small amount of heat escaping from SuperStor.
the superstore looses about 1 degree an hour
I'm in a very similar situation to yours last August. May I ask - are you happy with your new Buderus? I'm in the Boston area, about to replace a 30 year old oil-fired boiler with a gas system. I'm hearing conflicting things about the advantages/disandvantages of the modcon condensing units over the older designs. Internet postings seem to lean toward their advantages, but the plumbers I've seen tell me that a)my cast radiators and baseboards want water at 180, so I will lose the condensing efficiencies, plus b) the modcons are complicated to install, finicky to maintain, and have problems with sediments in water - so all in all, probably not worth it. Any light you can shed on this?
Keep looking for better plumbers.
Cart iron rads don't need 180° water when it 30° outside to heat your house.
If they were sized correctly to begin with.
Absolutely very happy,it came in at 91% efficient when he did a stack temp check! Not quite condensing levels but a 10% improvement over the Peerless and I'll never go back to a tankless coil! The Tech could have been better he really did not have his act together programming the Logamatic.
Originally Posted by plumbandplumber
Reply to plumbandplumber
Hi plumbandplumber (great username BTW),
My Buderus has been running since mid-October, and I've been very happy with it. This forum does not like posters providing prices, so I cannot spell out my monthly gas bill. But let's put things this way: based on average fuel oil prices in our area, my current gas bill is about the cost of 125 gallons of fuel oil. Last year I used 175 gallons to heat my house during the same period, so I'm seeing a very good savings over my old oil boiler. That cost also includes my domestic HW, which is now supplied by an indirect HW tank heated by the Buderus versus an old electric HW tank. My monthly electric bill has only dropped slightly since removing the old tank. The Buderus uses electric ignition compared to the standing pilot of the old oil boiler, plus the circulator pumps run more often with a modulating boiler versus the old ON/OFF systems. So my electricity usage for hot water has been a bit of a wash (no pun intended).
In answer to your questions:
(a) That sounds like you're getting bad information. During my Web research, I read numerous articles that stated that while mod/cons work best with radiant floor heating, they also do pretty well with cast iron radiators like yours (see Don't post links to other forums please.). With a mod/con boiler, radiators do not need to run as hot because the boiler runs more often. Old systems are "bursty" - they run hot for a short period and then shut down, while mod/cons run more or less continuously at lower temps. Here's another forum post that debunks what you're hearing: Don't post links to other forums please..
(b) Yes, mod/cons are more complicated to install and installation takes a bit longer. However, as with any technology or boiler make, it all depends on the experience of the installer. You need to find someone that has installed several mod/cons before, and with their popularity growing, that's getting easier. I do know that all the plumbers and electricians that worked on my system said they wished they could afford to install a Buderus, so take that however you please. And I would not call mod/cons "finicky". Yes, with an outdoor reset control, it takes a little bit of trial and error to dial in the boiler settings. But this is something you can easily adjust yourself. For the first month or two, my first floor zone ran 2-3 degrees cooler than my thermostat setting. I gradually boosted the boiler base temperature to address this, and now things are fine. My only complaint about Buderus is the way they designed the outdoor reset control panel. You have to remove the boiler cover (very easy to do), but the outdoor reset control block is seated upside down. However, you can pop out the control block and flip it over to play with the controls.
Another thing about mod/con boilers: assuming your boiler is located in your basement, the basement is going to run cooler. Mod/cons don't radiate heat like cast iron boilers. My basement runs about 52 degrees in the winter - cool but not excessively so. I think that's part of the reason my first floor was running a bit cool - the exposed copper pipes in the basement are losing some heat as the hot water crosses the basement before going up to the first floor baseboards. I'm in the process of adding insulating sleeves to these pipes to help with heat retention and I suspect I'll be able to lower the boiler base temperature and see better efficiency/savings.
I also like how small a footprint the wall hung Buderus takes up in my small basement, leaving me the option to finish the basement in the future for more living space (my house is currently only 1300 sq feet). While I have no plans to see my house anytime soon, I think the Buderus may be a good selling point.
The bottom line is, you may not see a dramatic savings in a mod/con boiler versus an older technology cast-iron boiler. But personally, I believe in always buying the best possible appliance/tool/vehicle that I can afford. You can drive yourself crazy trying to compare apples and oranges technology and calculating ROI. Use your best judgement and don't let conservative, set-in-their-ways contractors scare you away from "new" technology (I put new in quotes because the technology is only new to the US - these boilers have been very successful in Europe for years).
Last edited by beenthere; 01-12-2009 at 06:08 PM.
Reason: Removed links to other forums.
Thanks so much for the really informative links about mod/cons you sent me earlier. But the moderator deleted them before I could bookmark them. Would you mind terribly resending them to my email address? (its in my profile. Many thanks!)