EDR Calculation Questions

alexh · January 16

Good Morning,

I recently took a stab a calculating the EDR of all my radiators to ensure my boiler is properly sized. I came up with a total EDR of 393 for the radiators alone and the DOE says my boiler (Utica PEG150) is rated for 391 square feet of steam.

Room	Radiator Style	Height	Tube Count	Sections	Sq Ft EDR (table)	EDR
Study	tubular	20	6	20	2.67	53.4
Living Room	tubular	20	6	27	3	81
Dining Room	tubular	26	5	10	3.5	35
Breakfast Nook	tubular	26	3	13	2.33	30.29
Media Room	tubular	26	4	9	2.75	24.75
1st Floor Bathroom	tubular	26	3	9	2.33	20.97
2nd Floor Bathroom	tubular	26	4	8	2.75	22
Master	tubular	32	6	11	5	55
Upstairs Office	tubular	32	6	11	5	55
Foyer	tubular	25	3	7	2.33	16.31
						393.72

Here is an example of one of my radiators for reference (dining room)

https://imgur.com/a/oxXJSQm

Am i correct in concluding that my radiators are perfectly sized for my boiler or did i overlook something?

Thank you,

Alex

Jamie Hall · January 16

Can't think what you overlooked — and it does sometimes happen that the boiler is orrectly sized to the radiators!

ethicalpaul · January 16

Very good! Now for our curiosity, do you ever find the boiler cycles on pressure?

alexh · January 16

https://forum.heatinghelp.com/discussion/comment/1835235#Comment_1835235

Sounds like I have homework as i don't know what that means!

ethicalpaul · January 16

It's when the pressuretrol turns off the boiler temporarily because the pressure gets too high, then the boiler starts back up again within a couple minutes to continue making steam.

It's an indication of how well the boiler size matches the radiation. In your case I would expect that you would rarely experience it, maybe only when recovering from a several-degree thermometer setback.

alexh · January 16

https://forum.heatinghelp.com/discussion/comment/1835256#Comment_1835256

My boiler is almost constantly running when its really cold out and only turns off for a couple minutes (perhaps due to pressure?) I assumed this was mostly related to my improper near boiler piping. I plan on redoing it in the spring.

https://imgur.com/a/o9PdeGQ

ethicalpaul · January 16

Honestly if it is heating well and quietly I wouldn't spend the money on repiping it until it rots through and you have to replace it. That could be months or years and years.

It's not shutting off due to the piping, it is probably due to pressure. Have you serviced this thing in the last couple decades? The water looks atrocious and everything is pretty crusty. I wonder how clogged the pigtail might be, but thanks to the nice size of your boiler, many sins can be hidden. Edit: although I see you have added a low-pressure gauge recently so maybe it's fine. How do you have a low pressure gauge on it, yet you don't know what cycling on pressure is (not judging, just asking, as people who put a low pressure gauge on their boiler are usually aware of such things).

I pulled my Utica out of service because I wanted to replace it on my time frame and after busting it apart I saw that it looked like it had a lot more time on it. I don't hate Utica.

Your boiler is even smaller than you thought, it's a good size for your radiaton, it's 375 sq ft:

alexh · January 16

The attached photos are a bit old and the system has been cleaned a few times since then. I disassemble and clean all the parts before every heating season. My main concern is my high heating bills. During the winter months im seeing monthly bills north of $500 for my 1800sqft house. I'm sure some of that is attributed to poor insulation (of the house), but i assumed my boiler also isn't running efficiently.

My pressuretrol is set to 0.5psi with the differential set at 1. The boiler seems to hover around 0.5psi when its running, but I will say my pressure gauges both stop working pretty frequently and i'm not sure what's causing it. Also my sight glass gets pretty caked up with brown gunk only a couple weeks after cleaning.

Perhaps i need to blow down the system more frequently?

ethicalpaul · January 16

No, if you blow it down more, you will create more brown gunk (from the added fresh water).

Minimize any leaking or draining and if you really want to reduce the corrosion, add a product such as 8-way (sparingly).

The video below is your goal.

Regarding cost and inefficiency, there is almost nothing that could be wrong with your boiler that would harm efficiency. Every BTU that doesn't go up your chimney by definition is going into your house. How long your house holds onto it is the important thing as you indicated.

I will say my pressure gauges both stop working pretty frequently and i'm not sure what's causing it.

It's possible that the pressure isn't high enough to register much, even on a 0-3 psi gauge. My system is more oversized than yours and my pressure is 1/25 of a psi during the entire start of a call for heat until some of the radiators start filling up.

https://youtu.be/Bx8NryCUkng

AdmiralYoda · January 16

$500 per month doesn't sound too excessive to me. I have a similar sized house built around 1870 and we have blown-in insulation and replacement windows and doors. Still room for improvements in insulation but overall the house is pretty tight for its age.

In December we paid $330 for natural gas.

When we moved in the house 15 years ago (same boiler) we paid $350 for the coldest month and this was before we added insulation and better windows. $350 in 2009 money is about $525 in todays dollar, adjusted for inflation.

alexh · January 16

I just cleaned the pigtail, pressure gauge pipes, and sightglass. I blew into my low pressure gauge to confirm its not plugged. After running another heat cycle I noticed my pressure is around 0.1psi. Once the system cut off, I checked my thermostat. 62 degrees, despite being set to 70. I wonder what caused the system to shut off?

EBEBRATT-Ed · January 16

Either the pressure control or the low water controls.

If everything is getting gunked up how much MU water are you adding and how often?

ethicalpaul · January 16

https://forum.heatinghelp.com/discussion/comment/1835310#Comment_1835310

If your thermostat is set to 70 why was your temperature 62? Has it been 62 all morning or did you let it get cold while you were messing with the boiler.

Is your boiler often not keeping your thermostat satisfied?

alexh · January 16

There's a consistent mismatch between the thermostat set temp and temp it's reading. I wonder if it's just a calibration issue?

I don't add much water during the heating season (maybe every couple weeks). If we have a unseasonally warm day though and the boiler isn't consistently running, a lot of water accumulates in the boiler and exceeds the max water level. When that happens i'll drain some out. That's another reason i figured my flat spot in the header was problematic. It seems to take a long time for all the condensate in the system to return to the boiler. I've shimmed all my radiators towards the supply valve in the past and will have to check again to make sure nothing shifted/sagged. Any other ideas?

KC_Jones · January 16

"There's a consistent mismatch between the thermostat set temp and temp it's reading."

Need clarity on this. Are you saying it is set for one thing, reading something different, and not calling for the boiler to run? Or, is it that same case and it is calling for the boiler to run? Those are very different scenarios.

If you are having to drain water, that isn't a slow return, it's new water being added incorrectly. Leaking valve, bad auto feeder, failed internal coil for domestic hot water, several possibilities. If you also have a slow return, that can be clogged wet returns, those tend to corrode the most of anything in a steam system.

alexh · January 16

https://forum.heatinghelp.com/discussion/comment/1835329#Comment_1835329

The thermostat is always set to 70 and the boiler seems to keep the house around 62 (pretty consistently). I don't have an autofeeder or internal coil. It's got to be the wet return or water supply valve.

random12345 · January 16

Are they all American Radiator Corto? I'm getting a few numbers different. Check pages 5-8:

https://babel.hathitrust.org/cgi/pt?id=uiug.30112047386849&seq=7

Before 1943 the old tubular rads were 2.5" measured from center to center of each section, but then US Dept. of Commerce came out with Simplified Practice Recommendation R174. That went into effect in 1943 because the War Production Board wanted to conserve metal for the war. It's an interesting bit of history. See pages 1695-end:

https://babel.hathitrust.org/cgi/pt?id=mdp.39015035429805&view=2up&seq=1695&size=175&q1=r174-40

After 1943, rads became smaller and the spacing between sections went down to 1.75". The EDR changed significantly. I'd check this measurement on all your rads so you're getting more accurate numbers if you haven't done so already.

ethicalpaul · January 16

If we have a unseasonally warm day though and the boiler isn't consistently running, a lot of water accumulates in the boiler and exceeds the max water level. When that happens i'll drain some out.

This is very confusing to me. A boiler is very simple. It's a pot of water, that's it. There's no way for water to accumulate (add) to it. There are a couple ways that water could be leaking into it, but those would be issues that should be fixed.

There could be a clogged wet return but that wouldn't make the boiler overfill unless you added water to it at some point.

delcrossv · January 16

Automatic water feeder?

Lance · 4:11PM

May not have anything to do with the problem, but thermostats disagree with their thermometers for many reasons.

I was asked to artificially to raise the thermometer reading so to satisfy the miser.
I was asked to artificially to lower the thermometer reading so to satisfy the warm seeking occupant.
With mercury bulbs, contaminated mercury, usually identified as lead colored, "not shiny" can give a false on/off, or a too large of a droop.
And of course there is that damage problem.
The other problem is not really a problem but a setting. To allow for certain systems lead lag effect on heat comfort, a heat anticipator, "tiny electric wire heater" can be set to preheat the stat to shut it off the heat unit before the temperature setting is reached to allow for the overshoot effect of the heat system delivery. this is usually a balanced low volt circuit which must be set within the parameters of the control parts.
Stats that must be leveled and are out of level. Tilt problem.
Then there is the ghost affect of a heat or cool air blowing across or through the thermostat creating a false room reading.
I'm sure I kind find some more, but like the social problem also known as the thermostat wars.

Thermostat Wars.pdf

ethicalpaul · 4:23PM

With mercury bulbs, contaminated mercury, usually identified as lead colored, "not shiny" can give a false on/off, or a too large of a droop.

How dare you malign the reputation of a mercury thermostat! That behavior is not welcome here, flagging as abuse! 😅

EDR Calculation Questions

Comments

Categories