Boiler failed/Gravity-to-circulating conversion

ThePreservator

Good morning from Essex County N.J.!

Our 1955 boiler has gone to meet its American Standard maker, and is leaking.  I'm trying to scope the job as efficiently as possible.   Any advice would be appreciated.

1) Do you know a hydronics guy in this area (Essex/Morris/Union Counties, NJ.)  who's converted gravity to circulating systems?

2) Are there any photos you'd like to share of the primary/secondary piping loops Dan talks about in 'How Come?' and 'Pumping Away?'   I want to show my plumbers a picture in addition to a schematic.

3) Has any body used a reset control with exterior temperature sensor in NJ to allow for cooler boiler temperatures in the shoulder seasons?

4) The current system has (approx.) 2-1/2" pipes on the return and maybe 3" on the supply, two each.  Should we try to keep these 'loops' separate zones in the secondary loop?  Being a gravity feed system, each loop heats half of the first AND second floors.   Not a zone-by-floor option.   Or is it better to make it one big loop?

5) A 2-story extension (circa 1989) has no heating at all, other than electric baseboard.   I may want to install (someday, not today) a radiant loop in the first floor which is over an unheated crawl space.  Would I be wise to plumb in a pickup for that system in the secondary loop?

6) Boiler sizing -- it should be sized for the total heat loss (including the unheated extension) right?  Therefore, 'in theory,' the boiler would be sized properly for the whole house when I go to add the radiant loop, right?  I'd just be under-radiatored until that system goes in.  But let me know if I'm overlooking something.

7) I'll try to get some pix up on this post (like it is not long enough.) I hope that once the Honeywell Heat Generator and its 30 odd lbs of mercury is removed and the supply/return pipes in the secondary loop are downsized for the circulating pump, that I'll have room to push the furnace back a foot or two against the brick chimney stack.  That'd give more room in that part of the basement.  But maybe I am hoping for too much.

Just an ignorant homeowner here-- and grateful for any advice on one or more of my questions.

Thanks to all the contributors to this board -- it's the Royal Academy of heating.

**** Lunde

Brad White

Some thoughts

1) Do you know a hydronics guy in this area (Essex/Morris/Union Counties, NJ.)  who's converted gravity to circulating systems?

-Clammy, AKA Mr. Rohrenbacher, if I spelled that correctly, comes immediately to mind. Clammy?



2) Are there any photos you'd like to share of the primary/secondary

piping loops Dan talks about in 'How Come?' and 'Pumping Away?'   I want

to show my plumbers a picture in addition to a schematic.



-Throughout the site and others I am sure will be proud to show their work!



3) Has any body used a reset control with exterior temperature sensor in

NJ to allow for cooler boiler temperatures in the shoulder seasons?

-Anybody with an appreciation for energy savings. It is an essential part of the program.



4) The current system has (approx.) 2-1/2" pipes on the return and maybe

3" on the supply, two each.  Should we try to keep these 'loops'

separate zones in the secondary loop?  Being a gravity feed system, each

loop heats half of the first AND second floors.   Not a zone-by-floor

option.   Or is it better to make it one big loop?



For what it is worth, that is how my house is piped (1913 vintage, large CI rads.) Next year we add TRVs to the radiators as high limit devices. But the "gravity loop" runs on a Wilo Stratos Eco at very low speeds based on outdoor temperature (65F and lower) constant circulation essentially. A Taco iValve blends in the right amount of boiler water. Works great.



5) A 2-story extension (circa 1989) has no heating at all, other than

electric baseboard.   I may want to install (someday, not today) a

radiant loop in the first floor which is over an unheated crawl space. 

Would I be wise to plumb in a pickup for that system in the secondary

loop?



Yes, do it now. In my own setup, I have several spare valves ready to go off a P/S header. Short money.



6) Boiler sizing -- it should be sized for the total heat loss

(including the unheated extension) right?  Therefore, 'in theory,' the

boiler would be sized properly for the whole house when I go to add the

radiant loop, right?  I'd just be under-radiatored until that system

goes in.  But let me know if I'm overlooking something



Size it for the total ultimate heat loss, understanding that the chances of hitting your number exactly are not that great and that any boiler worth buying will modulate down to become the boiler you need.



7) I'll try to get some pix up on this post (like it is not long

enough.) I hope that once the Honeywell Heat Generator and its 30 odd

lbs of mercury is removed and the supply/return pipes in the secondary

loop are downsized for the circulating pump, that I'll have room to push

the furnace back a foot or two against the brick chimney stack.  That'd

give more room in that part of the basement.  But maybe I am hoping for

too much.



Save that sucker. What a find. Could be worth something to the right buyer. Not sure I would re-use it, but someone out there may.

ThePreservator

Brad - follow up on three points

Dear Brad,

thanks for the quick and thoughtful response.  I've already emailed Mr. R. (Clammy) privately.  My follow ups:

1) Your 1913 system you say has a 'gravity loop.'  I guess the quotes mean that the Wilo-Stratos ECO pump specializes in that nice, lazy slow movement that thermal expansion does so well?  I'll do more research on that pump.  But it looks cooler than my first three PC's.. I was looking for a disk drive!  Did you convert the dual-loop to a single-loop in your case?

2)  What boilers do you recommend?  One guy is favoring Peerless over Weil-McClain.  He says the cast iron is heavier.  I hope the new boiler will last 55 years, like the old...



3) If I save the Honeywell Heat Generator, I'd definitely recycle the mercury in it.  But is there any special cleaning required for 94-year old cast iron to get the mercury out?  I don't want to be breathing that stuff...  One thing I WILL save is the gauge which shows the height of water in the attic expansion tank.  It's a Philadelphia-made beauty.



Thanks, again.

Brad White

Gravity of the Situation

Greetings, happy to assist!



My 1913 system was already converted to a circulated system before we bought the house last summer. With three 007 circulators, I was moving over 40 gpm through a 82 MBH output boiler. VERY slow to warm and prolonged condensing for years. Knock on wood, it looks fine and we hope to get several more years out of it.



In addition to the gravity circuit (serves the main and second floor), we have fin tube added to our attic master bedroom and bath, with another fin tube circuit in the kitchen and one in the basement TV/hangout room. So no neat way to do this but to keep those zones for now.



But yes, I wanted to "start the flywheel" and using the Wilo seemed to be the right approach. I thought of using an indirect or hydraulic decoupler to allow the gravity itself to work its best, but too much space would be taken up with that.  It is all 2-pipe and large, starting at 3" then 2.5" and down from there. The radiator load is about 45 MBH so 4.5 gpm in that large pipe has nearly no resistance. I suspect that the gravity forces outweigh the circulator by far!



If you are going with CI, well, everyone has their preference. I would go Peerless only because I had one years ago and it would not quit. Cast iron nipples, heavier castings, not a shy boiler. But brand is one thing, the total package is the other- installation, the installer, service, who is out there to stand by you.



For highest efficiency, a modulating condensing boiler is hard to beat. But I would not expect 55 years out of them. I am partial to Lochinvar, Triangle Tube and Viessmann in that type.



Regarding the heat generator, if you have not already, (I mean, you KNOW what you have there), read up on how it works. The mercury is not miscible with water so I do not think that it migrates, but I would not drink the water regardless. But you are aware of mercury vapors, visible under UV wavelengths, as I recall. So do not expose to air. But by recycle, I was thinking in total, the device might have value (absent liability) to someone willing to put it back to its original use. Not for the faint of heart, but it did speed up the gravity process. I wonder how many are still out there?



Brad

ThePreservator

follow-on question: primary/secondary loop piping

On 'How Come' page 28, Dan shows a primary/secondary loop gravity conversion that appears to be like mine: twin returns/supplies to the left and right of the boiler. 

His diagram pipes return-to return and supply-primary-secondary in chain so that he has one circulating pump on the Right hand supply pipe.  The way it's diagrammed, that would turn the system into ONE loop and would reverse the return/supply direction on the left hand side. 

Is there any problem with turning the (smaller) return pipe into a supply pipe and the (larger) supply pipe into the return pipe? 

My idea is to put a T on the joined returns and pipe that into the boiler via the secondary loop.  Likewise have the circulating pump feeding into a T on the joined supply pipes (pumping away from the compression tank.)  That would keep circulating supply acting like gravity supply, keep the thermostatic radiator valves on the same side as the current valves, etc.

Any problems with this?

****