Retrofitting old steel S and R lines to rads

Shane_2

Hey, I thought I was the only Shane that posted here!, Just kidding

I did the same thing for a customer last year. My first question, Are the existing risers exposed or in the walls for each rad? If the existing are exposed, I would strongly recommend replacing them at the same time. On my job, I made two loops around the basement(seperated first and second floors) and used monoflow T's(one for each rad above new mains). With the new risers I installed new rad valves and return ells for each. TRV's would have been over kill here with the new zones. I than used fiberglass insulation on all risers(paintable, and to protect from scalding).

It just seems to me, if at all possible, I would change everything I could at the same time

If your risers are hidden in walls, I would do as suggested by others.

Good Luck

Shane F

s.brown

replacing old steel suppy and retuns to cast rads

we are replacing the complete old supply and return hydronic lines to allow for better use of basement ceiling space while finishing a basement. My primary concern is how to most easily disassemble the existing connections to each riser to the cast iron radiators with a tried and tested meathod.
Any ideas would be helpful!

Brad White_9

The right tools and a partner....

I just did pretty much what you are condsidering, 1922 gravity system, new copper main$ in the basement but kept the risers to the radiators. In other words, aside from TRV's at the radiators, all work neatly in the basement. 9 radiators, 18 connections in total, so this is what I did:

1) Drain the freaking system first Just to be clear!

2) Sawzall a section of pipe you want to remove. Two cuts to clear some space between the sections is helpful.

3) Spray WD-40 or other pentrating lubricant on the joint; let it sit an hour or so to work. (Lunch was my excuse.)

4) Place a backing wrench on the riser base elbow and you or a partner do the same to the pipe. Grip firmly then give it a good snap to start the process. Very satisfying when she starts to turn... remove the nipple piece, clean out the threads with a rag. You may want to "chase" the threads with a clean new male fitting and hand pressure. My goal was to have all exposed female elbow ends when done.

4A) As an alternate, scoring and smacking CI fittings with a small sledge hammer can be satisfying too but too violent in my case considering the possibility of loosening joints up inacessible risers. Fine for piping going to the scrap yard.

To finish my connections (all 1" and occasional 1-1/4" risers), I fitted the FPT openings with 'size by 1/2" bushings and PEX-AL-PEX fittings (5/8" Kitek K2's in my case). Your sizes and flow requirements may vary.

Connect the dots, new to existing. Took about an hour per riser pair, all told. My new branches each had ball and drain valves on each side. Helpful in that I was commissioning one radiator at a time and pressure testing as I went. I did this all over a couple of weeks part time.

My new mains (1" near the start and 3/4" at the furthest points) form a continuous loop around the basement (connecting in a large circle, not dead-ending). I get plenty of flow with a Grundfoss 15-58 on lowest speed. Very low pressure requirements that way and for relatively little pipe. Just a suggestion.

clammy

steel pipe cast fittings

If your removing all of the steel supply and return piping except for the riser i would either smash the cast iron fittings with 2 lump hammers or use a saw all or better yet a portable band saw less vibration if your afraid of causing leaks ,will you be repiping in steel or copper or are you going to do a home run system using pex as supply and reurn to a mainfold in or near the boiler .Doing it in pex with a good manifold (flow indicators and flow setters ) is a good way to go just remenber to do a heat lose ,check the edr and lose for each room and that should be able to run size wise for your pex 1/2 about 14,000 btu,s with a 20 degree temp difference and being each rad is being supplied seperatly all the rads will see the same supply temp meaning if your rads are over sized you may be able to use a lower water temp to heat them if your boiler can handle low temps with out condensing also look into thermostatic raditor valves great opitions peace and good luck clammy

s.brown

so we did it! Customer only had a limited budget. He left the existing ELECTRIC wall hung boiler. I gave him a beautiful new designed system including a replacement Baxi gas boiler capable of heating the home with use of a supply and return home run manifold system complete with 3 zones for 3 floors of htg. control, and also an Indirect water htr. He didn't want to do it for lack of funds.
We repiped up into the joist spaces with new steel piping and prepared it all for a 1 day boiler shut down. Had 10 rads and risers to redo. Would loved to update the valves etc. but no funds. Day 3 involved draining and cutting out all the old piping and started to reconnect with Wirsbo hePex, quick and easy method. Filled the system, removed air and the heat is on.
Thanks for the tips guys!! Anything to add??

Shane

Brad White

Yes, Shane- something to add...

Can you post any pictures? Sounds like a nice job adaptable to the Owner's needs and budget. Do share if you can.