EDR and margin of error

The_Gel

Hi everyone-



I posted yesterday about my boiler, which has gone kaput: <a href="http://www.heatinghelp.com/forum-thread/151222/Confirmation-of-boiler-failure">http://www.heatinghelp.com/forum-thread/151222/Confirmation-of-boiler-failure</a>



I've gone through my house and attempted to compute the total EDR of my radiators. I don't have the big Every Darn Radiator book. Instead, I just consulted some of the standard worksheets that ask about radiator type along with height and number of sections. Now, I'm not asking anyone to go and look up figures from Dan's book (I can pay for that if need be). Instead, I'm interested in your impressions as to whether I need to be more precise in my overall approach.



Four of my sixteen attached radiators (I believe the house originally had 18) are not represented in the standard worksheets.



One of these is a wall radiator. I made an estimate based on EDRs for wall radiators of similar dimensions. Only a couple of hundred BTUs ride on the accuracy of this estimate, so I'm not concerned.



The remaining three radiators are probably more consequential. These are unusual in that they are unusually stout - 16" - for six-tube radiators. For these, again, I just made a rough estimate of per-section EDR based on what was available for near-sized radiators.



After factoring in two possible pick-up constants - 133% and 150%, I came up with BTU's of 124488 and 140400. The boiler I'm getting rid of is rated for 187500.



Thanks in advance,

Kyle

nicholas bonham-carter

Boiler Kaput

The definitive boiler leal test is the overfilling of the boiler (which you have done), and then letting it sit for a day or two. Any leakage will be seen on the floor, or in the firebox.

Based on the pictures, I would say that you are correct in assuming a terminal leak.

As regards the figuring df EDR, take the end result of "square feet of EDR" of the radiators, and compare it to the same value as given in the boiler makers specs for the range of boilers they sell. Usually no conversion is needed to BTU.

Probably the leak in the return has cause a constant flow of fresh oxygenated water into the boiler, shortening its life, so don't forget to fix that as well.--NBC

The_Gel

Thanks

Nick-



Thanks for your quick response; I had the same theory about the wet return.



Kyle

Jamie Hall

There is

a pretty substantial margin for wiggle room in figuring EDR for a system.  As NBC said, the best approach is to look for a boiler which is reasonably closely matched to what you figure your EDR to be.  Within 10 percent for your EDR calculations is just fine.