New House, Many Questions

JB1414

I am buying a 2500 sf 1930's house in the next few days and have some questions to help decide what to do to the existing heating system before next winter. The current system is a 150K BTU Boiler supplying approx 12 radiators of various size and type. I have done a heat loss calculation and am only coming up with ~55k heat loss, main reason for the large discrepancy is the walls have been insulated recently, so the boiler is a bit oversize to start.



Looking at the piping installation, I am fairly confident it has always been a water system and not a steam conversion, a: because there is an ancient expansion tank still in use that appears original, b: the piping into and out of the radiators is at the bottom, doesn't appear to have been changed, and from what I can tell steam would have typically been enter high, exit low in a two pipe system.



The house is 4 stories if you count the basement, but only the first and second floor is currently served, the boiler is in the basement. There are currently two large loops that run the circumference of the basement, one for supply, one for return, both are closed loops. All the radiators are fed off branch lines of 1" pipe from the supply pipe and 3/4" from the radiator to the return loop. I assume this is designed to create some resistance so the water has more time to disperse heat in the radiator. The supply and return loops are approx 2.5", maybe 3" when close to the boiler. The boiler has been changed in the early 90's to a Burnham with a circulation pump installed. To add to the confusion, some of the radiators seem to suffer from low/ no flow I presume due to sediment in the piping but could also be valve issues, but they look like they have been installed from the start, so unless someone changed something, the valves wouldn't normally need to be operated.



Now to my questions, first, the radiators in the house need some love, they have old peeling paint and I want to rebuild them, not to mention some of the valves do not work. I have found a local (I am in MD) shop willing to sandblast and powdercoat for a reasonable sum, but I am wondering if I should be rebuilding them as well. I heard there used to be a company in Newark DE who refurbished them, but cant locate their info. Should I disassemble? Do I worry the high heat from powdercoat will hurt the paper gaskets? Anywhere to get the gaskets? None of the radiators appear to leak now, but not looking to put money into them to find they have developed a leak.



Second, I want advise to see if I should re-do the piping in the basement to a more modern design. I was envisioning cutting the supply and return piping where they turn up to the first and second floors, remove the oversize 2 & 3" pipe, run PEX to manifolds. This would eliminate some heat loss from the over-sized pipe, gain me some headroom, correct possible flow issues with blocked piping, allow me to create two zones, one for second floor, one for first. Anyone supportive or done similar? Any reason to just keep it the same?



Third, I want to add some radiators to the third floor. Only feasible way to route the piping is with PEX, with the boiler already over-sized I am thinking it won't hurt anything, any thoughts?



Third, boiler is a bit over-sized, but.... I was thinking of installing control to adjust boiler temp based on outside temp, and the boiler has the ability to reduce the nozzle down a couple sized to lower the overall BTU to maybe 135k, any objections.



Thanks in advance.

James Day_2

system

you seem to have a grasp at what needs to be done.  How old is the current boiler? It may be time to upgrade.  Cast iron rads are a great heat emitter.  If it becomes to costly you might want to look into panel radiators.  Buderus and runtal make some nice stuff.  You could set it up with manifolds just like you described.    James

Xray

Beware!

Remember that it is unlikely that you will be able to hook up radiators in series--the first ones in line will "steal" BTU's from the radiators further down the line. The existing cellar loops may even use monoflo tees to ensure enough feed while allowing flow to more distant radiators.  Zoning sounds like a terrific idea (and it is), but you will probably have to keep the2-pipe system.  Pipe size can be reduced.  Consider adding domestic hot water.  And at all costs--have fun!

RDSTEAM

sounds interesting

your gonna have fun with this one. I know I did when i turned my boiler disaster into a work of art. when purchasing manifolds, get the ones with circuit setters built in. this will help you adjust any flow mods needed. by the way, there are a few systems out there that are actually 2 pipe vent systems, where both tappings are on the bottom. pretty neat system if you ever see one, if not read dans books, they are in there.

icesailor

Questions:

I don't think that your system is what you think it is. I've never seen a gravity or FHW system that had 1" supplies to radiators and 3/4" piping on the return. And had a separate return. I think it was once a steamer.

There are no "gaskets" between the sections. Only push nipples.

JB1414

still have questions

Thanks for the comments guys,



Any concerns with powder coating/ heat? Rebuilding company in the MD area or should I attempt myself? Does it even need to be done or just a flush out?



Any thoughts on re-feeding the radiators vs. the large loops? Do I need to increase the circulation with smaller piping?

JB1414

still have questions

Thanks for the comments guys,



Any concerns with powder coating/ heat? Rebuilding company in the MD area or should I attempt myself? Does it even need to be done or just a flush out?



Any thoughts on re-feeding the radiators vs. the large loops? Do I need to increase the circulation with smaller piping?

Steamhead

I've heard that powdercoating

can cause radiators to leak, because of the very high temperatures involved or something like that. We recommend to our customers that they get rads repainted with a high-heat type of paint that adheres well to cast-iron. The peeling paint you typically see is likely ordinary wall paint, which can't take the heat.



What part of MD are you in? We're located in Baltimore, and specialize in steam and hot-water heat. I have actually seen gravity hot-water systems where the returns were one size smaller than the supplies, but would withhold judgment until we've actually seen yours.

JB1414

Eastern Shore

I am in Centreville MD, would you be willing to cross the bridge?

Steamhead

We've done that

e-mail me your phone number to allsteamedup at verizon dot net and I'll call you.



Check out this link, which shows a job we did in Easton:



http://www.heatinghelp.com/forum-thread/135345/MegaSteaming-on-Marylands-Eastern-Shore