There is a limit...

Jamie Hall

-20 F this morning, with about a 10 mph wind. For southern New England, that's chilly. It turns out that that's what Cedric can manage -- 86 degree temperature difference, but the poor old boy can't raise it any more. It did raise it from the 3 degree night setback, but can't get over that.

Nice to know where the limit is, anyway!

Anybody else?

KC_Jones

I made it to 4 ounces and had my low fire kick in today 7° OAT which is my design temp. No trouble maintaining 70, but as far as my radiation goes I was running full out this morning coming back from 3 degree setback. My radiation is 63600 BTU and my calculated heat loss is ~60k BTU. Running good now that we are up to 18.

Brewbeer

New baseboard system, 130 supply water temps. Got down to -13 last night (2 out now). 70 inside now, recovered nicely from a 3 degree setback.

sunlight33

I set the maximum modulation on Vitoden 200 to 65%, it had absolutely no problem with -9 last night, as a matter of fact I think it should be fine even at 50-55%.

Fred

No issues here with -5 and a slight wind. Last winter I reached my max at -20 with a wind chill of -40. At that temp, I'm not sure I could have recovered from any set back.

Aaron_in_Maine

Mine won't keep up below 0 degrees because of my own fault I took the heat out on the second floor when we didn't use it. Now we use one bedroom but I didn't put the heat back we just leave the door open keeps it around 64-66. I bought my wife a electric blanket instead when we moved our bedroom up there. My thermostat is set to 68 all the time but when it is below 0 the thermostat won't get above 66.

njtommy

Hydro air had no problems keeping up last night. 0-5 degrees last night. Was going to try and dial in my max supply water temp this am, but had to go to work. Instead.

ChrisJ

-5F with winds and as usual the EG-40 did just fine.
Had no problem maintaining 73F and even recovered from a setback. Peak pressure during the recovery was 0.75"WC.


Chances are I won't know my systems limits unless we see -30F here.

Jamie Hall

For what it's worth, some miscellaneous playing with numbers showed me that first, my system is limited by the installed radiation, not the boiler. Second, the boiler is uncommonly well matched to the radiation (it does shut off on pressure -- but it takes a run of at least 45 minutes to do it) (thank you, @Charlie from wmass and third, the gross efficiency of the system (BTU in from oil burned to heat loss from the building) is around 84% -- which for a non-mod/con system isn't too shabby (thank you again, @Charlie from wmass !).

ChrisJ

Jamie Hall said:

For what it's worth, some miscellaneous playing with numbers showed me that first, my system is limited by the installed radiation, not the boiler. Second, the boiler is uncommonly well matched to the radiation (it does shut off on pressure -- but it takes a run of at least 45 minutes to do it) (thank you, @Charlie from wmass and third, the gross efficiency of the system (BTU in from oil burned to heat loss from the building) is around 84% -- which for a non-mod/con system isn't too shabby (thank you again, @Charlie from wmass !).

They all are, that's what we keep saying regarding oversizing a boiler. A boiler that is 33% larger than the connected radiation will provide no more heating than one that is 0% oversized.

Jamie Hall

Actually, a bit of a fudge, there, @Hatterasguy . I didn't determine the building heat loss directly (that would be an interesting exercise, though!). What I did was note that the system, running essentially continuously (a minute off every 15 minutes or so on pressure) was able to hold the interior temperature constant, but not change it. The shaky assumption then is that installed radiation really is producing that 240 BTU/hr per square foot that we like to talk about! And I know what that is. That gives me the heat loss from the building.

Accurate? Hardly. But I doubt that it's much worse than anything else!

Infiltration -- oh yes indeed. I am quite convinced that it is a very significant part of the heat loss. This was on a not particularly breezy morning, but 50% may be low even so. I'm not at all sure that there is a good way to determine it, at least on a somewhat normal house -- there are simply too many variables. A new build, with excellent workmanship throughout (yeah, right) -- yes, and it would be tight enough that a controlled outside air exchange would be required (through a sensible heat heat exchanger, of course). But an ordinary house?

Maybe I should sit down and take the time to figure out what the calculated heat loss for this monster should be, and compare that!

njtommy

33%? I think your number needs to go up 17% lol

BobC

@Jamie Hall I think you are measuring the heat loss of that building accurately under real world conditions.

If the boiler is running constantly and everything is heated fully across you know whats going in to the building and you know the point at which you can no longer raise the temperature of the building.

That seems to be a pretty accurate measure of heat loss to me.

Bob

ChrisJ

What about heat from the boiler and pooping? Flue pipe too?

BobC

If his cellar is anything like mine it has little effect. It was -9F this morning and my cellar was 44F, large expanses of exposed foundation.

Bob

ChrisJ

Wow piping not pooping. Using my phone tonight and not used to it. Still

Steamhead

ChrisJ said:

Wow piping not pooping. Using my phone tonight and not used to it. Still

http://www.damnyouautocorrect.com/

KC_Jones

ChrisJ said:

Wow piping not pooping. Using my phone tonight and not used to it. Still

You wouldn't have that issue on an iPhone. lmao

Canucker

To be fair to @ChrisJ we do bang on about having an accurate heatloss and after looking at his steam set up he does take his heating to the extreme

Brewbeer

To test limits, I set the boiler (WHN 55) to 60% maximum fire yesterday to see how it did over the night when temps dipped to -10. A 60% output (~29K BTU), the boiler was keeping up with demand, although with all three zones running this morning the boiler supply temp was still a few degrees below the boiler's 130F maximum supply set point, and set-back recovery was taking noticeably longer.

Three lessons learned from this cold snap:
1) the heat loss calculated for the house (32K @ 0F, or 36K @ -10F) is too high (20% over estimation?).
2) the ODR can be further adjusted to decrease the supply water temps (from 130F @ 0F to 130F at -10F).
3) the boiler can be limited to a maximum fire of 60% in SH mode.

hvacfreak2

Knock on wood I have all the heat I have asked for. I really appreciate the help that everyone on here has given me. I am heating 431 sq.ft. with a Megasteam 396 and it hasn't missed a beat. I was really worried about the sizing especially with the low pressure I was seeing when I first fired up. It has really been easy on the oil consumption as well.

bmwpowere36m3

Brewbeer said:

To test limits, I set the boiler (WHN 55) to 60% maximum fire yesterday to see how it did over the night when temps dipped to -10. A 60% output (~29K BTU), the boiler was keeping up with demand, although with all three zones running this morning the boiler supply temp was still a few degrees below the boiler's 130F maximum supply set point, and set-back recovery was taking noticeably longer.

Three lessons learned from this cold snap:
1) the heat loss calculated for the house (32K @ 0F, or 36K @ -10F) is too high (20% over estimation?).
2) the ODR can be further adjusted to decrease the supply water temps (from 130F @ 0F to 130F at -10F).
3) the boiler can be limited to a maximum fire of 60% in SH mode.

Yup, mine's been throttled to 35%... but it did lose a couple degrees Saturday night into sunday.

ChrisJ

hvacfreak2 said:

Knock on wood I have all the heat I have asked for. I really appreciate the help that everyone on here has given me. I am heating 431 sq.ft. with a Megasteam 396 and it hasn't missed a beat. I was really worried about the sizing especially with the low pressure I was seeing when I first fired up. It has really been easy on the oil consumption as well.

431sqft?
Ah nm 431 sqft of radiation.

hvacfreak2

431 , is it a secret code like 420 ?

hvacfreak2

lol.

I was sitting here at the computer the other day and thought " man I wish there was a small radiator here near my feet ". I looked down at the lan cable that goes down to the basement through an existing hole. And remembered the capped take-off on the main near the hole. May be time to make it 440 ( I'm a Mopar guy anyway ).

Jamie Hall

Add another 14 and make it a big block...

hvacfreak2

Hatterasguy said:

Subtract 5 for the finest Chrysler engine ever built.

From a performance standpoint , no question. From an interesting , hobbyist perspective that goes to the first generation. Good grief I can't get started on this , lol.

Steam traps , I picked up some brand new DB and Mepco to replace my main vents. It got cold so they are just sitting here , lol.

Jamie Hall

Actually, just to throw a bit of a monkey wrench at this -- my favourite engine to play with was the 401 Buick nailhead (not the successor 400!). You could get a lot out of one of those with only a little effort. Of course, that assumes you could keep oil in it... the valve cover gaskets leaked like sieves...

ChrisJ

The only old car engine I've worked on and know quite a bit about is a Ford model A.

My dream engine would be any Harry Miller inline 8 or V16 but I've got a better chance of seeing god.

Fred

The Chrysler 383 and 440 would be my favorites. They ran forever if you took care of them.

ChrisJ

Fred said:

The Chrysler 383 and 440 would be my favorites. They ran forever if you took care of them.

I see quotes like this often from people but it often confuses me being these engines are from the days when you either junked the car or rebuilt the engine at 100,000 miles.

Being we often see 200,300 even 400,000 out of gas engines these days and from the 1980s-1990s I'm a bit surprised any 1950s-1960s engine would be described as "ran forever".


I'm sure I just threw water on a grease fire, but, that's ok. It's Jamie's thread.

Fred

@ChrisJ , they usually needed a valve job at 100K but they were simple to work on and I use to take the heads off, on a Friday night, run them to an auto machine shop on Saturday morning, pick them up on Saturday afternoon after the valve were ground, maybe a couple replaced and put the car back together on Sunday, ready for work on Monday. Carbs were a somewhat weak point too but you could take them off, go get a $30.00 rebuilt one, trade your core in and put in on in an hour or so. Of course, I'm sure everyone who ever owned a Chrysler (50's or 60's) remembers how the inside of the distributors would get damp, on rainy days and the car wouldn't start. OK, I take it back. Maybe they aren't my favorite, just fond memories.

ChrisJ

IMO carbs are a big reason engines weren't lasting.
Richer mixtures meant oil didn't work as well or last as long.

Put fuel injection in, run engines hotter and use modern oil and I think you'll see very similar results to more modern engines.

Fred

The oils weren't as refined and didn't do as good a job lubricating back then. Engine tolerances weren't nearly what they are today, Gas quality wasn't what it is today. Lots of things affected the life of an engine. Carbs vs Fuel injection played a part also. Plus the only thing that adjusted the fuel/air mixture was the gas pedal and a crude butterfly choke. Today's computer mixed air/gas was a huge improvement and much more effecient. They were easy to work on though.

ChrisJ

Fred said:

The oils weren't as refined and didn't do as good a job lubricating back then. Engine tolerances weren't nearly what they are today, Gas quality wasn't what it is today. Lots of things affected the life of an engine. Carbs vs Fuel injection played a part also. Plus the only thing that adjusted the fuel/air mixture was the gas pedal and a crude butterfly choke. Today's computer mixed air/gas was a huge improvement and much more effecient. They were easy to work on though.

Everything that was easy to work on is everything you never have to touch anymore so it's kind of moot.

Modern engines have no plugs, no rotor, no points and no carb to work on.

Fred

Everything that was easy to work on is everything you never have to touch anymore so it's kind of moot.

Modern engines have no plugs, no rotor, no points and no carb to work on.
Agreed. But when a computer controlled device fails, you pay through the nose !

KC_Jones

"Modern engines have no plugs"
Huh? So does magic ignite the air fuel ratio?

ChrisJ

KC_Jones said:

"Modern engines have no plugs"
Huh? So does magic ignite the air fuel ratio?

Diesels.

I meant wires, not plugs.

Fred

As best I know they have plugs that will last 100K miles. My Hummer is diesel, glow plugs

ChrisJ

Yeah,
What were plugs good for in 1960, 10,000 miles?

Fred

ChrisJ said:

Yeah,
What were plugs good for in 1960, 10,000 miles?

Yes! The problem with the 100K plugs is they weld to the heads in tht time and then they usually break off when you try to replace them. Then you end up pulling the heads anyway but at least that's at 100K