New boiler questions

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Old 03-03-13, 09:33 AM
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New boiler questions

Hi guys,


House background:
I have a ranch home in New Hampshire. It was built in 1971 and a few years ago it was renovated because of a fire. It has vinyl siding, Tyvek, new windows, new roof, 16 inches of blown in insulation in the attic. I've replaced one of the external doors and I know the outer walls are 2x4 with R13 fiberglass insulation. There is radiant fin baeboard throughout. The total square footage is 1460sq ft. 960 on the first floor and 500 in the basement.


I had my oil boiler(water system) cleaned yesterday and the tech that was working on it said that he felt that I needed a new boiler. He had pulled the jacket and showed me the top of the boiler where it was fairly rusted and wicking quite a bit of moisture. The boiler is a Burnham CB-4. I couldn't find much information about this boiler but I believe it is steel and not cast. It also has a tankless coil. The gross output is 141,000 BTU with a net of 127,000 BTU. I plan on getting another opinion but I started doing some research on oil boilers.


After reading much of the forum I know I need to have a manual J calculation done. Afer calling a few HVAC and plumber contractors, no one seemed to know what this was. They seemed more interested in the square footage and were recommending a boiler size of 100,000 BTU. So I guess my first question is, how do I find someone that can perform a manual J calculation?


Out of curiousity, I did a heat loss calculation using Slant Fins IPad calculator. It calculated 21,000 BTU's is needed for my house. A quick look online and it seems like it is tough to find an oil boiler this small. I found that Biasi has a boiler, the B-10, that is rated at 67,000 BTU; it was the smallest I could find. This would still be three times the size I need. Is this ok? If adding an indirect tank, will this change the amount of BTU's I need? Also, which BTU rating is more important, net or gross?

Any help would be greatly appreciated
 
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Old 03-03-13, 10:32 AM
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He had pulled the jacket and showed me the top of the boiler where it was fairly rusted and wicking quite a bit of moisture.
Implying that there is a leak in the boiler itself? Is that what he was saying?

Any components installed on the boiler that could have been dripping down inside?

Just saying that perhaps it's not the boiler itself leaking but something external that could possibly be repaired...

It also has a tankless coil.
Ughhhh...

Your thinking of going with an indirect if replacing the boiler is good. Yes, it will add about $1000-1500 to the price of the install, but worth it in my opinion.

Afer calling a few HVAC and plumber contractors, no one seemed to know what this was.
They didn't even know what it was? Ummmm, don't use them. Find a contractor that DOES know what it is, and is willing and able to do the calculation. Most won't do one for free, based on speculation of getting a signed contract, but any GOOD contractor should specify that he WILL DO ONE before selecting the replacement boiler size after they have a signed contract in hand. Make sure that the contract spells out in no uncertain terms that they will perform the HL calc...

how do I find someone that can perform a manual J calculation?
Keep calling... until you find one that agrees that the only way to size a replacement boiler is by a proper heat loss calculation.

I did a heat loss calculation using Slant Fins IPad calculator. It calculated 21,000 BTU's is needed for my house.
Being somewhat of a Luddite, I don't have an iPad, so I've never used their new app. I suspect it is at least as accurate as the old one. How much info do you have to input with that app?

21K sounds a little on the low side to me. I'm thinking more like 35-40 or so...

What temperature did you input for the "design temp" ?

I would recommend looking at the 'sticky' post at the top of the forum, DL'ing the old S/F program and running that to see what you get...

rated at 67,000 BTU; it was the smallest I could find. This would still be three times the size I need. Is this ok?
It sorta HAS to be... you won't find an oil boiler much smaller. A nozzle size much smaller than 0.5 GPH is hard to find. Smaller than that and nozzles tend to clog.

My recommended boiler would be the Burnham MPO in the smallest size.

MPO-IQ84 - Burnham MPO-IQ84 - MPO-IQ Series 64,000 BTU Output Oil Fired High Efficiency 3-Pass Boiler

If adding an indirect tank, will this change the amount of BTU's I need?
When sizing a boiler with an indirect, the requirement of the indirect is always going to trump the heat loss of the home. Going smaller than the indirect manufacturer rates the indirect only means that it will take a little bit longer to recover the tank... and the 'first hour' rating will be slightly less. Not to worry, either the B10-3 or the MPO IQ-84 will work fine with an indirect and be WORLDS ahead of that "thankless" coil you have now.

Pair it with this indirect and you can't go wrong:

AL35SL - Burnham AL35SL - AL35SL Alliance Hydrastone-Lined Indirect Water Heater

which BTU rating is more important, net or gross?
NET, OUTPUT, DOE
 
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Old 03-03-13, 01:40 PM
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I did a heat loss calculation using Slant Fins IPad calculator. It calculated 21,000 BTU's .
I agree with Trooper, 21,000 Btu/hr seems low. Better double check all your input data. By the way, the Slant/Fin program calculations ARE per Manual J.

I ran my house on the "old" Slant/Fin program (which was pulled off their website several years ago, allegedly because they needed to update the selections for selling their equipment). I re-ran two of my rooms, with the new I-Pad app, using the exact same input data as before. An exterior room came in with 3.8% higher heat loss and an interior room had 2.2% higher heat loss. The I-Pad program is obviously doing something a little different, but not significantly so.
 
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Old 03-03-13, 02:35 PM
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Thanks guys for the response.

I think what he was trying to imply was that he felt that the boiler could start leaking internally at any moment. The only time I've noticed water around the boiler was when the emergency switch was turned off upstairs. Other than that it's always been dry. I don't think anything is leaking from above; everything looks really dry. I was looking online for the manual for this boiler hoping to see a breakdown of the boiler to identify which part was rusting and wet. Either way, I think I'm convinced that it would be nice to replace it and having the indirect tank would be a big improvement.

I re-ran the numbers with the Slant Fin desktop client and it came in at 36,746 BTU/HR. Looking at the IPad app inputs I fat fingered a few things and missed a few options. For an outdoor temperature I used 0 degrees but after looking up this value, I noticed it should be -3. After correcting the mistakes, it came in at 37,600 BTU/HR. About a 2% difference from the desktop client. So your guesstimate was right on.

Just curious why the Burnham over the Biasi? Is the Biasi less reliable?

Again thanks for all the help.
 
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Old 03-03-13, 03:31 PM
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why the Burnham over the Biasi? Is the Biasi less reliable?
Blue boilers are best...

I like the MPO for it's ease of cleaning, but I have to say I've never cleaned a Biasi so it may be just as easy... I sorta don't think so from looking at the pics I've seen. An easy clean means it is more likely to be done properly, more often...

The MPO "IQ" controls are a nice feature. Allows a simple plug and play selection of Outdoor Reset, and I forget what else... but there are three option slots.

Don't know about NH rebates, but in NJ the MPO qualifies for a $300 rebate. (didn't check the list to see if the Biasi does or not, it might) DO check for rebates from your state before deciding!
 
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Old 03-03-13, 03:33 PM
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Is there any more information on the boiler data plate? I'd like to know exactly what you have there.

I think what he was trying to imply was that he felt that the boiler could start leaking internally at any moment.
Sounds like a "salesman's scare tactic" to me.

Something you should know...

It's highly likely that if a tech 'sells' a boiler, he gets a little something extra in his paycheck.

Keep that in mind.
 
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Old 03-03-13, 04:09 PM
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I think what he was trying to imply was that he felt that the boiler could start leaking internally at any moment.
I don't suspect dishonesty, maybe just aggressive salesmanship. But it reminds me of gas stations on the route to Florida that would squirt oil on the rear shocks and then advise the Yankee driver that he must have his shocks replaced. They had two motives: money and getting even with Gen. W.T. Sherman.
 
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Old 03-03-13, 04:33 PM
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I don't suspect dishonesty,
No, me neither, not exactly, but 'caveat emptor' should still rule the decision.
 
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Old 03-03-13, 05:27 PM
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Yeah like I said, I plan on getting a second opinion. There was really no pressure. It was more like a, oh by the way.

When boilers start leaking, do they just let go or does it start as a small leak? In other words, is there a chance I would come home to a flooded basement?

Thanks again for all the advice and help.
 
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Old 03-03-13, 05:55 PM
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When boilers start leaking, do they just let go or does it start as a small leak? In other words, is there a chance I would come home to a flooded basement?
The real question is whether your boiler is leaking at all. (If it is leaking, and depending where the leak is, then the boiler may need to be replaced.) Can you post photos of the area of the supposed leak? There is a chance you are being scammed.
 
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Old 03-04-13, 05:47 AM
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kraymondksc,

i recently replaced my 13 yo DHW heater. it started leaking very slowly first and then gradually it got worse. i installed a new heater and i also installed an automatic valve that detect water on a floor and shuts off the water intake.

since my DHW and boiler share the same line, i installed it upstream from both. so if something goes terribly wrong at least it won't flood my basement. my boiler intake is closed all the time, but in case i have open at some point, it would help.

here is the valve i installed: Amazon.com: Water Heater Auto-Shutoff Valve: Electronics
 
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Old 03-20-13, 07:41 PM
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Is gas available

Hi,
Sorry if I mised it but is NG available? If so do not ever consider oil. Gas will save you probably at least 50% over that way oversized oil boiler.

Tom
 
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Old 03-21-13, 05:14 PM
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As I understan it Gross. Net is if the boiler were in the back yard.

Do you have NG at your location? If so do not even consider oil.

Tom
 
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Old 03-21-13, 05:20 PM
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It seems that, like Elvis, the O.P. has left the building.
 
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