Help with Boilers

Mike T., Swampeast MO

With cast iron radiators I highly recommend a condensing/modulating boiler.

Absolutely INSIST that a heat loss calculation be made--with and without your anticipated thermal improvements. Get as many of those improvements as possible done ASAP and size for the "improved" condition. Oversizing a modulating boiler will prevent you from getting the highest benefit in moderate weather.

If you can at all afford, consider adding thermostatic radiator valves (TRVs) to your radiators.

None of the condensing/modulating boilers have been around long enough to have a reasonable estimate of life expectancy. The design of some does [seem] better than others. Those with aluminum heat exchangers are much more likely to need water treatment/monitoring. This can be an expensive proposition when your system holds a lot of water.

Choosing a condensing/modulating boiler based only on lowest price of the unit itself may not be the best way to approach the situation...

BigColdHouse

Help Replacing Boiler

CAN YOU HELP ME? I am struggling because I have received so many quotes for a new boiler system. Never mind price, I am overwhelmed by the differences in opinion that contractors have about what I should get.

House is 3500 square feet, 3 stories plus basement.
On one hand, I have been recommended a new:

Trinity 200,000BTU high efficiency-modulating boiler. The boiler will be piped with a primary secondary-piping configuration. The existing cast iron radiators will be run off the primary loop. Included in the install will be a system pump, auto feed, back flow, expansion tank, low water cutoff, removal of old boiler and all other necessary materials. AND

To supply and install a new 60 gallon indirect hot water tank. The tank will use the boiler to heat the water. A pump and thermostat will control the system. Included in the install is a mixing valve, system pump and all other necessary materials.

OR IF I DON'T WANT THE INDIRECT HOT WATER TANK...

Supply and install a new Buderus 187,000BTU Mid-efficiency boiler. The boiler will be piped with a primary secondary-piping configuration. The existing cast iron radiators will be run off the primary loop. Included in the install will be a system pump, auto feed, back flow, expansion tank, low water cutoff, removal of old boiler and all other necessary materials.

I lean towards getting the high efficiency one, but I have been told by 2 contractors that they have had problems with the Trinity. One said don't go with an indirect hot water tank, as you can have trouble linking this to older piping, related to the flow switch. In one instance, he said, the problem resulted in the thing staying in the heating mode constantly.

My other issue is the size. I don't think I need a 200,000 BTU. I think that may be oversized. We are renting now, but will have within a year or so, two adults and two children living in this house. At the moment there are 2 other adults- but while they are living here, the children will still be under 5 yrs. and often share bath water, so I think it will always be as though we have no more than 4 adults living here.

We had a Greensaver Home Energy Audit done- the result was a design heat loss of 152,753, but they said I could achieve 136,000 this fall with the thermal upgrades I have planned. The assessor didn't know what the additional water demands would be on the indirect system though. Would a 150,000 BTU be sufficient? Is there something in between?

Please help if you can. With the high cost of energy and a house that had heating bills of over $700.00 in the colder months last year, I am anxious to make these upgrades ASAP. But feel stumped with my lack of knowledge and indecision.

Confused in this,
BigColdHouse

thp_8

well

a) I would first ask what is the problem with the old one? b) I would buy insulation 1st. This year it will be cheaper than oil. And no I don't work for the (owens corning) boys. c) ask your fellow neighbors who is good? d) in a older home alot of times the connected load of the system is more at fault than the boiler.

Joy DeSanctis

american standard steam boiler model A34M

I REALLY, REALLY NEED HELP LOCATING ANY INFORMATIOIN ON AN AMERICAN STANDARD STEAM BOILER MODEL A34M PROBABLY FROM THE MID 1960S. ANYONE WHO MIGHT HAVE AN OPERATIONS MANUAL, OR SPECS OR ANY INFORMATION, ANYTHING AT ALL. ANY IDEAS ON HOW TO GET INFO OR WHERE TO GO. I HAVE CONTACTED BURNHMAM AND THEY REFERRED ME HERE, SO I AM TRULY DESPERATE FOR HELP, ANYTHING, PLEASE. ANY THOUGHTS

THANKS JOY DESANCTIS

Edward A. (Ed) Carery

A question for Joy????

Joy,

Are you the person who posted the thread BigColdHouse?
If you are not, I think you may have accidentally posted your request into an ongoing thread about a different topic.

You should post it as a new topic, and start a thread on it alone. You will get much better results.

Good Luck

Ed

Steve Ebels_3

Cast iron rads and high tech boilers

A match made in heaven. As Mike said, if you can find it in your budget, adding Thermostatic Radiator Valves to your rads will greatly enhance the system. If you can do that, you can now run constant circulation for the entire house, probably a very small circ will do. A condensing and modulating boiler that is equipped with outdoor reset is a perfect mate to this type of setup. The fuel savings will likely run in the 30-40% range.

As to your DHW question; a good indirect will recover hot water very quickly and a good control package on the boiler will include DHW priority. Those to facts coupled with the high mass of your system mean that you won't have to add any btu capacity for the DHW. What happens is this. The rads are running constant circ at low to medium temps so they are warm, the dhw priority switches the boiler briefly to recharge the tank. Your high mass rads still give off heat while the dhw tank is brought back to temp. Chances are very slim that you would even notice the switch while dhw is made.

Insulate, insulate, insulate. 'Nuff said on that topic.

My personal favorite is the Viessmann Vitodens. It comes with all the features I listed above and most likely would be simple to pipe into your existing system. You have a main supply and return pipe on your present boiler. Now envision replacing your existing boiler with a pair of closely spaced tee's. The supply and return from the Vitodens would simply pipe into those tees. A second set of pipes that the Vitodens comes with connects to your indirect tank. They will use either the circ on the Vito or a seperate circ depending on the size you go with. If required flow rates permit, it's possible that the onboard circ on the Vito would handle the whole thing. That's something a good contractor would be able to say yes or no to.

I would be very tempted to use the model 8-32 Vito with a variable output of 33-112 MBTU. The reason for this is that I've found typical manual J heat loss calcs to have noticeable "cushion" built in. Another reason is that a manual J doesn't take into account internal heat gains from the rest of the things found in a normal house like lights, cooking, laundry etc. At 136,000 btus, your heat loss is almost 39btu's/sq.ft. That is a little on the high side for a typical structure unless you have a lot of air infiltration. JMHO

Dan_26

time to replace the old boiler

Whats the proper way to come up with the right size of steam boiler.Presently It has a cracked Burnham V73 and doesn't heat the house properly. House is a two story,single steam system and there is a 20º difference between the two floors. Am i correct in believeing that you measure the radiators in each room by HxWxL add them together and come up w/a total sq ft of heating surface?. and any recommedation on boilers whould be a help.. like Peerless, W/M, ect thanks for your help

Steve Ebels_3

Dan

You need to re-post your message under its own topic. Go back to where you see (NEW THREAD) and start there. This post began regarding another topic for discussion and you'll get more responses if you start your own.

Constantin

Go with the right size...

... insulate the place first to reduce the heat loss, then assess just how much energy is needed to keep the place comfortable. I find it surprising that your heat loss is 136kBTU/hr on a design-day after having it insulated, that's almost 40BTU/sq ft... that heatloss is close to what our house lost on a design day before we insulated.

Be that as it may, there are a number of low-mass condensing boilers out there that will make your radiators sing and reduce your gas bills accordingly. As the professionals here have pointed out, a low-mass, condensing, and modulating boiler like the Trinity is a perfect match for radiators, particularly if you take advantage of outdoor reset and/or TRVs.

As for what brand/kind of boiler is best, I'd let the experience of your local installer guide you. From the little reading I have been able to do about the Trinity, it has impressed this mere homeowner. The modulation range for the Trinity is quite wide so that it can take advantage of a better insulated home in the future.

Edward A. (Ed) Carery

To Dan

Dan,

Steve is correct, you have to post this in its own thread. Let us know if you do & what name the new thread is under so we can follow and try to help.


More important, the LxWxH of a rad is NOT the square foot capacity of the rad.


The sections differ in that there are column, tube, wall hung, etc., and the number of columns or tubes in the individual rad sections has an effect on the capacity of each section, and therefore on the overall output of the rad.


The height of the section is measured then the section sq ft rating of that type of section is determined using a rad capacity chart such as IBR or equivalent. Multiply that capacity times the total number of sections equals the rad output. All rad output added together is the boiler sq ft capacity needed.


Most tables for calculating rad output also have a factor built in that picks up the pipe loss.


Good Luck


Ed

Edward A. (Ed) Carery

To Dan

Dan,

Steve is correct, you would be best served to post this in its own thread. Let us know if you do & what name the new thread is under so we can follow and try to help.


More important, the LxWxH of a rad is NOT the square foot capacity of the rad.


The sections differ in that there are column, tube, wall hung, etc., and the number of columns or tubes in the individual rad sections has an effect on the capacity of each section, and therefore on the overall output of the rad.


The height of the section is measured then the section sq ft rating of that type of section is determined using a rad capacity chart such as IBR or equivalent. Multiply that capacity times the total number of sections equals the rad output. All rad output added together is the boiler sq ft capacity needed.


Most tables for calculating rad output also have a factor built in that picks up the pipe loss.


Good Luck


Ed

Dan_26

thanks Guys will do...all new to me

Bob W._3

Sizing radiation

Dan, this is on Burnham's web site. Use to measure and size radiation.

http://www.burnham.com/Sizing.cfm

RoosterBoy

sir , i think that sounds a little bit

too much of a bad thing. what i mean by this is somewhere in the interpretation of the whole deal ...needs to be something that addresses the extraodinary loss of heat from your home. where do you live? i think insulation would be the first choise of expenditure. after that a blowerdoor test.

you may disagree ,thats ok. genius i have heard described as "fluidly adjusting to ones environment".

maybe you dont quite need to buy into any boiler or system at the momment... for some reason this is what i seem to think you need to hear.