condensing boiler

Billy_3

I just did a house with 3 loops of baseboard and an indirect. The boiler was free from the gas company and I though it was going to be a Burnham series 2 power vented boiler. When it came it was a Burnham revolution which is a condensing boiler and I put it in because I didn't think it made a difference. Then I just read the post about the ultra which is also a condensing boiler and people are saying your not supposed to install a condensing boiler with just high temperature baseboard. Am I going to have problems? The boiler is pretty much installed other than the gas piping.

Kal Row

the revolution is a perfect fit

for you baseboard system - leave it,

baseboards need temps hotter than the condensing temp of flue gasses, so while the ULTRA will work, you cant get the most from it

the revolution, will do just great - dont make yourself crazy

R. Kalia

no it isn't

> it was a Burnham revolution which is a condensing

> boiler


It is NOT a condensing boiler. It has built-in p/s piping and allows low water temperatures, but it is not a condensing boiler.

Unknown

The Revolution boiler

is not a condensing boiler. It can condense in the stainless vent piping and a provision is made to collect that in the boiler vestibule. It is able to handle return water as low as 55F without condensing due to the internal bypass and variable speed pump. It works well with all types of hydronic systems and provides high 80% efficiencies without condensing. hope this helps.

Glenn Stanton

Burnham Hydronics

Billy_3

ok

Ok great. That is all I wanted to know. Thank you very much. I thought that if there was any condensation in the flue that it was a condensing boiler. If it is not a condensing boiler does that mean I don't need a condensate pump because there is a spot where the condesate drains out

Unknown

Depending on

the ambient temperature of the basement and the distance of vent pipe and fittings, as well as the temperature of the combustion air you are bringing in, you will tend to make some condensate in the flue. This amount will vary based on the above and running times. We always advise collecting and disposing of the condensate by an approved method. A condensate pump is usually that method. If you are not making any condensate, then we advise priming the trap in the boiler base with Propylene Glycol to keep the seal in the trap from evaporating.

Glenn

jaybee

condensing boiler

What is a condensing boiler?

Kal Row

ok, here goes

flue gasses cooled to less then 136f will condense, this will corrode a heat exchanger that is not designed for it, like cast iron, on the other hand, aluminum, stainless, or copper, handle it just fine

why would you want to condense?
so that the returning water could suck every drop of heat out of it

now if you have a baseboard system that’s designed to supply at 180 and return at 160 – then you cant use a condensing boiler since at 160, not only couldn’t you extract heat out of less than 136f flue gasses, you might actually loose heat to the gasses

however if you have a radiant slab – that supplies at 110 and returns at 90, you can suck every drop of heat from the flue gasses, thus weil-mclain can rightly claim 98% in that application

the revolution has internal protection from cold return water that might cool down the heat exchanger to 136f, with an internal mixing bypass loop

Boilerpro_3

180Fsupply/160F return only needed a couple days a winter

A 180F high temp baseboard system only needs to operate at about 140F supply and 128F on an average winter day, allowing you condensing capabilities on most of the winter. All it takes to make this happen is having outdoor reset control on the boiler. It is easily added or comes as optional equipment on most boilers.

You could also just add some extra baseboard and drop its temperature so at design you only need 140F supply. Then on a typical winter day your supply temp would be nearer 115F and return about 100. At this temp you make lots of condensate.

Just some added thoughts.

Boilerpro

Unknown

Baseboard

If you were to use Slant/Fin 81A MultiPak 80 baseboard, and designed for 130° F water temperature, you would use 330 BTUH per foot. That still is a reasonable amount of baseboard in a room, in most climates.

If you then reset the water temperature with the outdoor temperature, you can be in condensing mode most of the time.

Avoid short zones that have a narrow delta T. If you have a lot of zones, consider using zone valves, and leave the end switch disconnected on one or two short zones. They will still respond to their own thermostats, but will add their load to whatever other zone is running at the time. This adds loads together to reduce short cycling of the burner. Run the wires to the end switches and then you can experiment by lifting only the ones that you want to, and later change your mind.

Noel

Kal Row

yes but not with baseboard

when you put in a tekmar 361 pri/sec/mix, you tell it what the "terminal unit" is, ie what type of load you have, i have never seen it drop the mixed temp below 140 on baseboard, it wouldn’t, since baseboard needs a considerable delta-t on the air, to convect it well, it is NOT known as a low temp device, so while the 120 return in this case is in the condensing range, it's real borderline price wise
,
in nyc, the return water temp in the condensing range would be no more than half the winter at most - i could be wrong - i have to check the GAMA tables - it's usually not worth the diff in price, - but then again, in this case the diff from a revolution to an ultra is only a grand – and gas is only going up – on the other hand, he already has the revolution installed, ah, decisions, decisions, decisions!

Ps: the half winter 120 return, is important enough to require cast iron boiler protection via mixing, which the revolution does provide. built in – so it runs at the temp. where it’s most efficient, and only long enough to provide, the total btu needed, – like I said, real borderline, which would be more efficient at the end of the day

Tony_8

white lies

So don't program it for bbd. Try low mass concrete setting.
I think a 361 on a Revolution would be overkill also, you would need a buffer tank to keep the boiler from short-cycling wouldn't you ? Designing the system to need lower temp water at design and then letting it "float" on constant circ let's it "reset itself". No good for zoning though.

Just my thoughts.

Kal Row

your right, the revolution doesnt need a 361

but it also supposed to have rudimentary short cycle protection in it's own electronics - so i don’t think it needs a buffer - so he can use it as is, just fine

what would be nice, is a two stage thermostat, to kick in the circulator first - and then the heat on second stage – studies have shown, that to be, one of the biggest money savers

think about it, 50ft of baseboard holds 1-galon of water, not much heat storage there, but if you start circulating, you can extract residual heat from the boiler, and system, and even out the temps in the house

Boilerpro_3

On the 361, you can program your own curves

The type of heat emitter mainly sets the shape of the heating curve. If you go into the advanced programming settings, you can set your design water temp wherever you want and the control will just follow the same shaped curve, but at a different slope.

I have an injection set up in a multizoned house with mostly baseboard and the design temp is set at 150F at -5F and the baseboard modulates right down to 70F on warm days. In fact, the homeowner set all the thermostats all the way up for several days in milder weather(30F) and the temp in any of the zones never went above 73F.

Boilerpro

Tony_8

sounds like

System 2000 ?

I've been using Teledyne's Endurance, the Revolution must be similar ?

Kal Row

yep, but

the endurance is more efficient - the revolution is more reliable - i have changed an endurance (edp – with DMHW) inside 10 years for someone, only to have to change the water flow switch on the new one, just after a year – you cant pay me to put in one of those again – should have known, when they named it endurance

Kal Row

maybe i havent play with it long enough

the last one i installed is set or 180 at 10f - and injects 143 on a 37 day, and none of my tekmar 510's call for more than 70 in the space,

you acctuly get usable convection on baseboard temps below 120? slantfin's baseboard tables stop at 140 - please point me at data - thanks

Unknown

Data

Boilerpro_3

Yep, study the tekmar manuals' closely

and you'll see some pretty neat things when you look at the reset curves for different types of heat emitters. The curve for radiant floor has a much different shape than one for baseboard,for instacce. The differences are much more than just the target temps.

Always learning here on the Wall.

BP

Kal Row

which book

the seems to be the less than 3ftps correction factors for the ibr steam to water radiation conversion table

cant actually tell the real btu you can get, or if the heat transfer is efficient, is there info on how i can convert it to actual btu per ft, and efficiency? – sure you get some heat every time you have any delta T – even 1 degree, but is it efficient and usable in the real world

none of my searches came up with more data - maybe we should start a thread with the title “low temp baseboard” to get more input - because if we can get the heat out of a baseboard with 80f water as efficient as 140, in a 70 degree room, only less btu’s - then this changes everything - the ultra would be the best boiler then – to bring you up to temp quick, and then maintain the room temp efficiently with low temp water in fully condensing mode – instead of mixing down from a non-condensing boiler – man, I am dieing for real hard science!!!


ps, this is a great page to send homeowners, they also think that baseboard is meant for 140+
http://www.nahbrc.org/docs/NewHomeButtons/ConferencesandSeminars/4178_energyinenergyout_ted.pdf

Confused_2

Weil GV series and Burnham Revolution

Sounds like the Weil-Mclain GV Series and the Burnham Revolution boilers are the same animal. Both have an internal mixing logic/pump to protect themselves from low return water temps and both need stainless steel exhaust to handle any condensate. They are higher efficiency boilers but not to the level of a modulating boiler like the Ultra. ~88% Were these boilers designed to fill a gap in the market were the installation needs a self protecting boiler but not carry the cost of a condensing/modulating boiler?

Unknown

Differences

There are several differences between the GV and Revolution boilers. The GV originally utilized a thermostatic actuator to activate the bypass circuit. They have utilized several pumping/piping configurations since and are now on their 6th revision of configurations as far as I recall. Burnham utilizes a standard gas train with Smart Valve and HSP. GV has a counterflow flue gas configuration with a bottom discharge.

The Revolution utilizes a variable speed pump (007) within the internal bypass piping to control flow through the boiler and injection into system via a Tekmar based VSP controller. has been and continues to be very dependable, simple in design and operation, affordable and highly efficient (mid to high 80% range with copper fin).And in answer to the last question.....yes....whether that was intended or not! Hope this helps.

hydronicsmike

What??

Why can't Baseboard (or Fin Tube Convectors) be reset any lower than 140°F Supply?? Although very little, it still puts out heat at lower temps, doesn't it?

On a tekmar Reset Control, if set for Outdoor Design of 10°F and Boiler Design of 180°F, the Controls would roughly target 85°F Supply at 65°F Outdoor and roughly 106°F Supply at 55°F Outside. We wouldn't target anything close to 140°F until we roughly have an Outdoor Temp of 35°F. Of course, that is based on a CONV Terminal Unit and "Baseboard" with 480 BTUhs at 180°F with 20°F deltaT. Give or take a couple of degrees on the numbers quoted. I am just going by gut feeling on this one. Did any of you ever run into trouble heating a house with this type of Baseboard while run at these low temps?

hydronicsmike

KAL, are your...

...ROOM and INDR settings at 70°F?

Kal Row

yes

Floyd_5

Glenn,

The most recent GV that I have installed used an injection system similar to the revolution system.
The problem with these deals is that it is hard to determine if the pump fails.

Unknown

Actually Floyd

It is quite simple to determine if the injection pump is not working as desired on the Revolution boiler. Simply look at the boiler temperature gauge, the % On light on the VS3000 pump control and feel the system supply pipe. If the boiler is at or near high limit, the LED % light is on solid and the supply line is not hot, then the pump is not performing correctly. Hope this helps.

Glenn

Confused_2

Actually Floyd

I believe you can perform the same kind of analysis on the GV. A failure of the system pump would produce the same results as you describe. A failure of the injection pump could be determined by comparing the return temp just before it enters the boiler with the return temp "after" the injection pump. (just before it enters the block). If it is the same temp as the return temp entering the boiler either the pump failed or the computer is malfunctioning. This of course depends on how hot the return water is! This effect is more pronounced at cooler return temps. Example would be 100 degrees return into the boiler and 140 degrees after the injection pump into the block. The problem is how are you alerted to this problem other than a yearly PM ????

Floyd_5

Your right....

many times things will "appear" to be working when they are not.....all this equipment is just fine and dandy, however the tech. better keep a sharp eye out for the sutle little things.