Boiler Size

jeff_51

It was the guys on this site that gave them to me. I bought a new file cabinet to put the stuff in that I download off of this and other sites

Adam_14

Boiler Size

Had a new boiler installed at the beginning of the season - oil-to-gas conversion. Problem is, at least a half dozen or so radiators aren't heating up, while others only heat when I remove the vents.

The original contractors never did measure the radiators - which I've since learned is sop with new installations. Rather, they went off the size of the oil boiler.

My questions:
1) Can someone instruct me in how to go about measuring radiators?

2) Was it a mistake to use the size of the oil boiler as a reference? And if so, why?

Appreciate the help. Adam

Brad White_28

Adam-

> Had a new boiler installed at the beginning of

> the season - oil-to-gas conversion. Problem is,

> at least a half dozen or so radiators aren't

> heating up, while others only heat when I remove

> the vents.

>

> The original contractors never did

> measure the radiators - which I've since learned

> is sop with new installations. Rather, they went

> off the size of the oil boiler.

>

> My

> questions: 1) Can someone instruct me in how to

> go about measuring radiators?

>

> 2) Was it a

> mistake to use the size of the oil boiler as a

> reference? And if so, why?

>

> Appreciate the

> help. Adam

Brad White_28

Adam- Steam

SOP for steam is off of connected radiation and piping.

SOP for hot water is from calculated heat loss taking into account current improvements made since the old boiler was installed.

It is a mistake in my opinion to use a nameplate replacement especially if hot water which is not your case.

Let's take your system being steam. Nameplate replacement may well be OK if it was sized correctly in the first place and if you have not removed or added radiators. But how would they know without checking? Or asking?

If hot water, without knowing the current heat loss, you lose the opportunity to capture improvements you have made to the envelope. Say the old boiler output was 100,000 BTUH, sized years ago when the house was uninsulated and drafty and the heat loss was actually at 100,000. Theoretically perfect, but this is all hypothetical here...

Since then you have blown in insulation, replaced the windows, caulked the seams, re-sided the house and added Tyvek... Your actual heat loss is now, say, 65,000. If a 100,000 BTUH output boiler was installed, you are, right out of the gate on the coldest day of the year, almost 50 percent over-sized. It is all downhill from there. You are double over-sized on an "average" winter day... The boiler will cycle on-off (unless you have modulating fire), and hence lose efficiency due to repetitive start-up and cool-down cycles.

This is for hot water, not applicable to you. I should have read your reference to "vents" more carefully

To perform a take-off on radiators, there is a book available on this site EDR (Every Darn Radiator), worth it if you are really into this stuff. For short-hand, browse the Burnham Boiler web site. They have cast iron radiation and a chart with obsolete sizes. Not so comprehensive but gives you an idea for 90% of what is out there. Within 10% I would say.

You need to know the type (small tube, Fero, Column, Federal being several). Number of tubes per section (viewed from the end). Section C-C dimension. Normally 1.75" for small tube and 2.5" for others. Height also plays a role of course.

You will get a certain number of square feet EDR (Equivalent Direct Radiation) per section. Multiply that out by the number of sections and you have total EDR for your radiators. I would add 10-15% to account for piping if you want a quick-check, but ideally take off piping by size, length and condition (insulated or not).

If steam, each EDR is worth 240 BTU's per hour.

If hot water at 180 in/160 out/170 average, it drops to 150 BTU's per hour.

wsdave

Books

As a home owner with a single pipe steam system I would HIGHLY recommend that you get Dan's books "We Got Steam Heat" & "Lost Art of Steam".
Both will help you answer your questions and more.
These books and all the pros here have helped me diagnose what is wrong with my system and what to do.
If you are not mechanicaly inclined then there is always the Find a Pro section on this site.
Dave

Adam_14

Thanks to both of you for taking the time. I'm new to this site, and simply amazed at not only the quality of information, but also how helpful everyone is. I'll be sure to check out the Burnham site as well as the books. Thanks again. Adam

jeff_51

go to the following

http://www.colonialsupply.com/resources/radiator3.htm and heatinghelp.com/pdfs/92.pdf should get you what you are looking for

Adam_14

Jeff- Thank you! These sites are great. Even a laymen like myself should be able to decipher. Thanks again for taking the time. Adam