Converting from EG-45 to EG-40.

ChrisJ

Mark N said:

Chris, what was the design temp that was used when the rads were installed? You way well still be above that number. It would not surprise me if that number was -10 degrees.

I don't know, wasn't around back then.

Design temp to the closest city with similar temperatures is 4f right now. System run time @ -5f with some wind was approximately 20 minutes twice an hour.

Mark N

I would think modern design temps have no corrolation to what was used 80 to 90 years ago. I was at zero this morning and the design temp for my area is 10 degrees. On Monday when I last checked with a simiar temp it was running about 25 minutes and then off between 50 to 60 minutes.

vaporvac

My original paperwork says my system was designed to run at 72deg at 0deg design temp. I live in Cincinnati and the system was installed in 1914 if that's a help to anyone. I think my design temp is still rated at 0deg. today.

ChrisJ

Mark N said:

I would think modern design temps have no corrolation to what was used 80 to 90 years ago. I was at zero this morning and the design temp for my area is 10 degrees. On Monday when I last checked with a simiar temp it was running about 25 minutes and then off between 50 to 60 minutes.

Curious why you are concerned about design temps from back then, if they even exist? They also designed our systems to heat the bedrooms with the windows open at night, but we don't do that anymore.

My total cycles were around 20 minutes on, 10 minutes off give or take. I'm running 2 cycles per hour which the EcoSteam enforces for the most part.

Mark N

Chris, I'm sorry I'm being literal again. You said the temp was 9 degrees below design. But if 4 degrees was not the number used when system was designed, you may well be not 9 degrees below design day temp. My house was built is the 1930's and I don't think by then the open window thing was done. My bedrooms all have smaller rads than similar sized rooms on the first floor. The cycling is very interesting 20 on, 10 off. One would think it would be closer to 15/15. But you have a EcoSteam also.

ChrisJ

Mark N said:

Chris, I'm sorry I'm being literal again. You said the temp was 9 degrees below design. But if 4 degrees was not the number used when system was designed, you may well be not 9 degrees below design day temp. My house was built is the 1930 and I don't think by then the open window thing was done. My bedrooms all have smaller rads than similar sized rooms on the first floor. The cycling is very interesting 20 on, 10 off. One would think it would be closer to 15/15. But you have a EcoSteam also.

Mark, never apologize, I enjoy the conversation!

Yeah, by 1930 the open window stuff was gone, luckily. I was 9 degrees below the current design day temp for the area. Yes, you're right, I wasn't 9 degrees below the system's design temperature as that's somewhere around -40F. I certainly hope I never see that.

Just keeping the thread up to date in regards to the boiler with only a 10% piping/pickup heating the house properly under extreme circumstances.


15 on 15 off wouldn't be long enough to heat the house at that temperature. That would be more along the run times when it's around 16f or 17f outside.

ChrisJ

MarkS said:

Every time you put a new boiler in, or change the building envelope (insulation, new windows, etc) you effectively change the design capability. A colleague's home has about a 100 MBH heat loss and a 91 MBH DOE net boiler. He's struggling to maintain temp. But when he fixes the drafty doors and windows, that will change. It would be interesting to know some facts about the boiler in @ChrisJ 's home when it was first built. That would tell you a lot about the original design intent.

Sadly, this is something we will never know.
The coal boiler was long gone by the time I got there. Only thing left are some pieces in the crawl space, some baffles and a pulley from the damper system hanging on a floor joist.

Though, keep in mind when the house was first built it had several wood or coal stoves. The steam heat was added many years later.

Mark N

What happened to using 3cph.

ChrisJ

Mark N said:

What happened to using 3cph.

Worked really good until it got in the 20s out. Then it kinda, went down hill. The VisionPro would run two really short cycles, then one long one to catch up.

Mark N

Read page 16 of TLAOSH. Starting with the paragraph about the basic premise of the 2 psig standard. This was how systems were designed. Nothing about design day.

ChrisJ

Mark N said:

Read page 16 of TLAOSH. Starting with the paragraph about the basic premise of the 2 psig standard. This was how systems were designed. Nothing about design day.

You can't size radiation based on pressure.

Mark N

Yes you can, the higher the pressure the hotter the steam and the more EDR per sq ft of rad. At 1 psi each sq ft radiates 240 BTU's per hour at 10 psi it's 368 BTU's per hour. Since we use low pressure our radiators were sized at 240 BTU's per hour. Also 240 btus is only valid with a 70 degree ambient.

vaporvac

That's true MarkN. However, I have the original specs and plans to my heating system and it was designed to heat to 70/72deg on a 0deg day. This is 1914 so I guess they thought about it when installing the radiation, but didn't call it "design day". It is interesting to ponder how they designed these systems originally. Does anyone else have their original specs?

Mark N

I don't have any specs from when my house was built. I would think at that time most heating contractors built their system to maintain 70 at zero. According to the table on page 16 of TLAOSH if built to that spec would be able to maintain 63.1 at -10. In the case of my house and Chris J's and many others they even oversized above that. At full capacity my system can provide 64.4 btu's per sq.ft. per hour.

Fred

I read an article somewhere. May have been in one of Dan's books where the Dead Men tested a system, after installation, on new houses by building a fire in the boiler and they had to maintain a temperature inside the house that was 70 degrees above the outside temperature for a 24 hour period. The assumption was that 0 was the design day. Not very scientific, especially during summer months but it was a strategy, I guess. Once they passed that test, the system was approved by a local inspector.

Mark N

That is what is being discussed here. But think about this the same radiators put out different amounts of heat dependent on the temp of the room. The 240 btus per sq ft is based upon a room temp of 70. The same rads emit more heat per sq ft if the room is colder and less if the room is hotter. If the room was 212 degrees a fully heated rad would emit no heat. I would think the chart in TLAOSH is related to different outputs of rads based upon the room temperature.

ChrisJ

The point was you don't need a 33% pickup factor for the system to work correctly.

Mark N

What pickup factor do you think should be used? Possibly 15% like in a hot water system. There must some reason that 33% was settled upon in the past. I would think if the boiler was truly undersized, meaning the gross output of the boiler was less than the connected EDR of the rads, at times the boiler would perform unsatisfactorily. I would think it would start to become more noticeable the larger the system became. Possibly not able to get any steam to the furthest rads.

ChrisJ

Mark N said:

What pickup factor do you think should be used? Possibly 15% like in a hot water system. There must some reason that 33% was settled upon in the past. I would think if the boiler was truly undersized, meaning the gross output of the boiler was less than the connected EDR of the rads, at times the boiler would perform unsatisfactorily. I would think it would start to become more noticeable the larger the system became. Possibly not able to get any steam to the furthest rads.

I don't know.
I believe @JStar has been using 10% or 15% typically.

Dave Brunnell has far more experience with this than I do and I believe he is also against 33%. In fact, I believe he feels you should use the heatloss of the house rather than match EDR.

https://heatinghelp.com/systems-help-center/taking-another-look-at-steam-boiler-sizing-methods/

Mark N

In hot water heating they use a current heat loss of the structure plus a 15% pickup factor.

SWEI

Mark N said:

In hot water heating they use a current heat loss of the structure plus a 15% pickup factor.

Unless the system is using ODR with constant circulation and minimal or no setbacks -- which eliminates the need for pickup. Piping factor is still an issue in some cases. I tend to think the "fudge factor" in heat loss calcs probably ends up as a piping factor.

ChrisJ

-8f and still no problems.

ChrisJ

A new video showing pressure with a 10f ambient and the stable water line. I'm fairly sure the water line is more stable since I installed the smaller burner.

The pressure was about the same when it was -8f out, doesn't seem to drop much more than this even when everything is cold.

Turn up your volume to enjoy the music. There are lyrics, they're just......quiet.

https://youtu.be/hH36luC9GKU

ChrisJ

Just did a 4 degree recovery with 10F ambient from 68F to 72F.

Not a sound from any radiator and absolutely zero overshoot. I wanted to see what pressure the system was running at but it shut down just before I got out of the shower.

What I do know is it never shut down on pressure (1 ounce limit) so it was under that.

ChrisJ

Some pictures of this morning's recovery.


39.75 minutes into the recovery. Cycle almost over.




Details of the cycle.



Data after the cycle.



Pressure near the end of the recovery. This was after 40 minutes of continuous firing.

vaporvac

What is your set-back?

ChrisJ

vaporvac said:

What is your set-back?

Right now, 68F at night, 72F during the day.
So 4 degrees.