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Joined on March 5, 2010

Last Post on January 28, 2014

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@ January 28, 2014 10:40 PM in Will the combustion exhaust from my condensing gas boiler harm my home's brick outer wall?

Thanks all for your input. The exhaust currently is pointed along the side of the house. Once it warms up a bit, I will go out an change it.

Will the combustion exhaust from my condensing gas boiler harm my home's brick outer wall?

@ January 14, 2014 3:53 PM in Will the combustion exhaust from my condensing gas boiler harm my home's brick outer wall?

I had a Buderus condensing gas boiler installed several years ago. The installer explained that a PVC flue is used for the combustion exhaust because it is acidic. If I were to send the exhaust up my terracotta flue, the acid would eventually cause the flue to degrade and collapse.

Well, that has got me thinking about the outside of my home where the exhaust comes out. I have a brick home, and the exhaust comes out right up against the side of the house. I am sure that some of the moisture in the exhaust ends up on my brick. So I am wondering if I should be concerned about the long term impact on the brick. Would the acid from the exhaust gas begin to degrade my brick? (Similarly, the condensate is pumped out onto the ground right outside my house - how may that impact my cinder block foundation.) Has anyone looked into this? Is there any need for concern? If so, what would be a good remedy?

Thanks, Ed

One other question

@ October 15, 2010 11:50 PM in Outdoor reset question with Buderus GB142

Thanks Ironman,

One other question.  I notice that there is a post purge feature on this boiler.  After the call for heat is over, the boiler circ keeps going for a set time.  However, the thermostat has shut off the zone circ.  What is the purpose of the post purge timer, if my zone circ is off, and so I can't get the heat from the boiler to where I would like it?

two zones

@ October 15, 2010 7:47 PM in Outdoor reset question with Buderus GB142


I have two zone: the basement and the living area; one circulator per zone.  There is an external relay box (an Argo AR861-2II).  The thermostats and line power are wired directly to the Argo.  The line power then goes to the boiler, plus a control signal to the Buderus AM10 outdoor reset controller.  There are no zone valves.

Is it easy to wire it to have the outdoor reset control the circulators?

Also how much does it matter?  My heating contractor says that it doesn't matter (aside from the cost of electricity to run the circulators) and that it is even better for the circulators to run continuously.  I was concerned that the circulators are running with a starved suction if the boiler circulator is off, but my contractor says that there header below the boiler allows the water to circulate through the zone, even if the boiler circulator is off - is this correct? 

Outdoor reset question with Buderus GB142

@ October 15, 2010 1:29 PM in Outdoor reset question with Buderus GB142

I had a Buderus GB142/30 with an indirect DWH tank installed this spring.  I am just getting around to using the heat now (didn't need it in July - Ha!), and I am trying to understand what the outdoor reset is supposed to control; the boiler and the circulators, or just the boiler. 

I came home the other night, it was 70's outside, and I have the hi temp shut-off at 65 temperature.  I went into the basement, and noticed that the basement zone circulator was running - the basement thermostat was calling for heat.  The boiler, of course, was not running.  I was expecting the outdoor reset to turn off the circulators when it shuts off the boiler.  I haven't checked, but I presume that the same happens when the DHW calls for heat; that the zone cirulators still run if needed, but the boiler circulator turns off?  

So, is it ok for the zone circulators to be running while the boiler circulator is off?
I looked at the setup diagrams that came with the boiler, and the outdoor reset.  It does not apear to show a control from the outdoor reset and the circulators.
Thanks for any input

Gas vs Oil as a heating fuel source

@ March 16, 2010 11:16 PM in Gas vs Oil as a heating fuel source

I couldn't find any recent threads on the benefits of using gas or oil versus the other.  I have my opinions, but would really like to see what others think.  I am interested in any aspect of the discussion from economics, political stability of the source countries, impact on environment, as well as, is there any benefit to having a burner running on gas vs oil?
Thanks for your input!

Buderus condensing GB125 boilers

@ March 16, 2010 9:40 AM in Buderus condensing GB125 boilers

I was talking to a heating contractor about the Burderus condensing oil boiler yesterday. Do people have experience with these boilers?  I have not seen a price on these so have no idea what the payback time would be.  I am wondering what people's experiences are with the operation and reliability of these boilers.

room by room

@ March 12, 2010 10:50 AM in Buderus GB142 vs Burnham Alpine

I haven't done a room by room heat loos yet.  I see now what you are talking about.  That will take a bit more work.  And yes the customer (Me :) ) may not have the fund to replace any baseboards this year, but at least I can figure out where would be the best place to start when I get to it.


@ March 12, 2010 10:46 AM in Buderus GB142 vs Burnham Alpine

I got if off the Slantfin website, but it was a while ago.

More from Stuck

@ March 12, 2010 1:55 AM in Buderus GB142 vs Burnham Alpine

Charlie - By radiant, I presume you mean radiant floor heat?  Yes I only
have copper fin baseboards. 

Quick review of my project:  Currently have a dying Burnham 5 section V7
(190k BTU) - but I can, and would like to switch to nat gas.  I have
about 118k BTU of copper fin baseboard (ONE zone, plus the basement).  I
haven't found a contractor YET who does actual Manual J head loads
(sigh!), but I have run the slantfin program, and IF I plugged in all
the values right I have somewhere about 90k BTU heat loss at -10 F (we
might see this temp once every year or so).  At the typical coldest
nights of the year my circulator is not running anywhere near all the
time (I guess < 75% of the time) - so my 90K BTU heat load may be
correct???   I am an engineer by day and only pretend to be a heating
person by night (Ha Ha) - while very interesting I'd really rather be
playing with my kids or reading a good book!

I am open to replacing some of my baseboards (Chris - with what?) to get
better heat exchange - and then be able to run lower temperatures
(would that be important if I am already maybe 30% oversized on the
baseboards?)  I am thinking my $ may be better spent first on sealing
leaks, etc.  I have pretty even heat, even with the single zone.  This
is a VERY solid 50 year old home - it leaks a bit here and there - but I
know that I can improve the envelope. 

I have one quote on a Burderus, but they have never installed a
mod/con.  I just contacted another contractor today that has, it sounds
like he may even do a heat calc! (Buderus also is the favorite of one of
the main local wholesalers, so that speaks well for me).

I have read enough to realize that I won't get top efficiency from a
modcon on the coldest days.  But I presume that with my currently
oversize baseboards, that I should get some benefit compared to if my
baseboards were "properly" sized.

Bottom line - presuming that the Buderus modcon does "crap" out on my
like the Burnham did - I should be able to expect to come out ahead vs a
conventional gas boiler - no?



What are my objectives

@ March 11, 2010 6:59 AM in Buderus GB142 vs Burnham Alpine

Thanks for all the input. It is all very interesting.
As I read this I ask what are my objectives?  First is RELIABILITY, and second is lowest overall cost (installation, repair, fuel).
After federal and Virginia rebates I can get a GB142 for a couple hundred less than a GB124 (w/o ODR).  Based on that I am leaning toward the GB142.
I like the lower fuel use of the mod/cons, and their fancy controls, but ultimately however, I want a reliable boiler that won't send me to the poor house.

Aluminum vs Stainless Steel

@ March 10, 2010 5:37 PM in Buderus GB142 vs Burnham Alpine

Could someone comment on the differences between an aluminum and stainless heat exchanger.  I know that aluminum has a much higher thermal conductivity (that is good!), but many people clearly don't care for aluminum. 
Do you have personal experiences of problems with aluminum?
Buderus claims that they have been making aluminum heat exchangers in Europe for decades.  Do they have corrosion problems?

I'll look for an installer in my area

@ March 10, 2010 8:55 AM in Buderus GB142 vs Burnham Alpine

I have read really good things about the triangle tube prestige.  I think I may have to go at least an hour away to find someone to install/service these boilers, but I will give them a call.
So you can get these with a "built-in indirect"?  Is that like the DHW coil in my current (rapidly dying) Burnham V7 boiler, only I wouldn't need to keep the boiler hot 24/7/365?  In other words, are these essentially an "on-demand" water heater?
As for condensing...What is the maximum water return temp to condense?  Do any of the boiler control modules have the capability to target running at a condensing temperature unless (for example) it sees a continual drop in the room temp?  How does yours work?

Buderus GB142 vs Burnham Alpine

@ March 9, 2010 11:16 PM in Buderus GB142 vs Burnham Alpine

I need to replace my boiler and am looking at one of the high efficiency
mod/con models.  I  particular the Buderus GB142 and Burnham Alpine
both seem good, and are available through local contractors.  What kind of experience do some of you have with these boilers?  I have read here that some people are not fond of aluminum heat exchangers, and comments about pH.  If I go with the aluminum Buderus do I need to check the boiler water occasionally, and add additives?  I read the Buderus installation manual, but it wasn't really clear.

Any other comments on the operations, controls, ODR function, etc. would also be appreciated.



@ March 9, 2010 11:26 AM in Several boiler installation problem

You must be looking at a different warranty than I can download from their websites.  The warrany I can find explicitly EXCLUDES labor of any kind, even in the first  year.
Please send me a link to the warranty you are looking at.


@ March 8, 2010 2:33 PM in Several boiler installation problem

Wow, thanks for the info on the snow!  Definitely a big snow year here.  We got the most snow of the last 15 years this year (and we missed a couple big ones that hit DC/MD).  I'll have to ask about venting a mod/con out my chimney where my current oil fired boiler vents.

50 yr old oil tanks

@ March 8, 2010 10:07 AM in Several boiler installation problem

I still have the original 50 yr old oil tanks (2 - 275 gal tanks).  They are in my basement.  The outsides look good, but I can't tell you about the inside.  I have not inspected.
I seem to hear various opinions about the hi-efficiency mod/con boilers vs. the standard 80-85% boilers.  The concern that some raise is that the mod/con parts are much more expensive, and so the maintenance can erase much of the savings in fuel.
I live in the Shenandoah Valley in Virginia.  I know of several Burhnam installers here.
As for length of baseboard - if I have equivalent of 120MMBTU/hr of baseboard (@ 180 F) but a max load of ~100MMBTU/hr I should be able to run a significantly lower boiler temp most of the time - correct?

OK, thanks

@ March 7, 2010 3:20 PM in Several boiler installation problem

I only have two zones - the living area, and the basement - so I can't do much with zone controls.  I am however interested in an outdoor reset.

I did the heat loss calcs myself using the Slantfin program because I couldn't find a contractor in my area to do them.  I live in a "smallish" town - most either want to put in the same size boiler, or want to size based on baseboard.  I used the coldest temperature I have seen in 15 years as my design temperature.

As for my circulators, they are on the return.  I have read much on the wall about pumping away.  My current system, however seems to be running fine.  The circulators are quiet, no indication that I am getting cavitation, and I don't ever get air when I bleed the vents on the baseboards.  Based on what I have read, I understand the advantages of pumping away, but since my current system seems to run fine, is it worth the added expense of repiping the circulators on my new boiler?



@ March 6, 2010 2:22 PM in Several boiler installation problem


I have 161 feet of copper fin baseboard in my living space, plus another 31 feet in my semi-finished basement.  I was using the value of 600 BTU per foot.

On the Burhnam would the rebate apply only if installing one of the two oil boilers you mentioned, or could it apply if I switched to a gas boiler too?

Several boiler installation problem

@ March 5, 2010 7:43 AM in Several boiler installation problem

I need to install a new hot water boiler on my home.  I currently have a 5 section burhnam V7 with a crack in it (burhnam will only give me $ for a new boiler if I install an EXACT replacement).   Boiler is about 13 years old, house is 50 years old.   My total baseboard radiation is about 120k BTU/hr (most of this is one zone for the living space, with a little for a second zone for the basement).  I am currently very comfortable in my home, and even on the coldest nights (0 F) the boiler seems to only run about half the time.    Most boiler installers around here do not do heat load calculations - they either want to install an identically size replacement boiler (about 190k BTU/hr) or they size on radiation.  I ran a heat loss calc using the Slantfin program which gave me a load of about 100k BTU/hr.

Couple questions: 
1. If I install a ~100k BTU/hr boiler for my home am I at risk of cold spots since I have radiation for 120k BTU/hr?
2. Do I risk problems with cold water return shocking my boiler in this case as well?  I see that the Buderus has a built in cold return bypass.  How about other brand (I also have quotes on a NY boiler, Weil McLain, and Burhnam)?
3. My current circulator setup pumps INTO the boiler on the return.  It seems to work fine.  Is it really necessary to add the expense to repipe for pumping AWAY if my current setup works?

Thanks for the input.