Completely Draining and Purging a Copper-In-Concrete Radiant Heating System

AlexPetron

Hello. My family's approximately 2,500 sq. ft. home is around 65 years old. It is constructed mainly of 8" thick concrete (floors and walls) with an above ground unfinished basement (unheated), a main level (heated), and an unfinished attic (unheated). The rather non-conventional copper radiant single-zone heating system installed at construction was embedded directly into the concrete. Recently it has been sprouting leaks. And when pressure is put to close up one leak, another weak spot in the copper spaghetti sprouts a new one.

I am not a plumber, so I am reaching out to all of you pros here. But despite my lack of professional skill set in the Plumbing field, I have reached the unscientific conclusion that this 65-year old system has most likely reached the end of its useful service life. So I am seriously contemplating retiring the system. However, I want to avoid further damage to ceilings, floors, and walls from bursting pipes and more leaks. So I would like to drain and purge the system of all water possible, and am asking you if fully draining the system would effectively prevent such damages.

As to its replacement, I am considering natural gas-fired forced hot air. Personally, I prefer a water-based system (like hot-water baseboard or radiators) as I feel it is much more comfortable. But I am sick of dealing with leaking pipes and tracing back leaks, and the particular construction of my family's home presents a unique challenge for the installation of ANY system, let alone a water-based one.

Right now, however, my priority is on preventing future damages and preserving the home even if it means it spends the rest of the Winter unheated. I am interested in your professional opinions on the matter.

hot_rod

An air compressor will blow all the water out, although once pressure is released it should not cause problems if further leaks occur.

You might consider one of the "dry" over the top radiant systems, unless AC is on your wish list too?

Radiant ceilings, walls, panel radiators, plenty of hydronic options.

neilc

you don't say where you are, or how cold it is or will get there,
but job one is a toss up, keep the heat on or keep the house dry.
will the domestic freeze? or drain that also(?)
Need someone there to pipe in baseboard, pronto.

AlexPetron

The home is in New Jersey. If draining the domestic water is necessary to get by the balance of the winter, I guess that would have to be done as well. I just think throwing much more money at this existing radiant system is a waste at this point.

neilc

electric heaters at homedepot

AlexPetron

Hey hot rod_7,

hot rod_7 said:

An air compressor will blow all the water out, although once pressure is released it should not cause problems if further leaks occur.

You might consider one of the "dry" over the top radiant systems, unless AC is on your wish list too?

Radiant ceilings, walls, panel radiators, plenty of hydronic options.

How do you mean "it should not cause problems if further leaks occur"? Do you mean that leaks from an inactive system aren't as voluminous as those from a recently decommissioned system?

hot_rod

AlexPetron said:

Hey hot rod_7,

hot rod_7 said:

An air compressor will blow all the water out, although once pressure is released it should not cause problems if further leaks occur.

You might consider one of the "dry" over the top radiant systems, unless AC is on your wish list too?

Radiant ceilings, walls, panel radiators, plenty of hydronic options.

How do you mean "it should not cause problems if further leaks occur"? Do you mean that leaks from an inactive system aren't as voluminous as those from a recently decommissioned system?

Boilers are often connected to an automatic fill valve that keeps the system pressurized.

Once that valve is turned off water will not continue to flow out of a leaking pipe, except for the 10 or so gallons in the piping and boiler itself.

As others mentioned all the water lines and traps under fixtures need to be winterized. Either blow them dry or add a non toxic RV antifreeze to the system.

Good job for someone experienced with winterization and geared up for the task.

Jamie Hall

Step 1 is going to be getting through the rest of this winter -- if you have the electrical capacity, yeah -- Home Depot or Lowe's and some electric baseboard. Cheap. The electricity costs will encourage further repair.

If you drain the water out of the radiant system and then shut it off -- and can keep the rest of the house warm (sort of) you can keep using the domestic water, of course -- except for one thing. What heats your hot water? If it is a separate water heater, you're fine. If it's the boiler... um, not so much. And you may have to get yourself a new hot water heater. You don't mention your current fuel -- but gas, electric, and oil water heaters all work well.

On the new system. It is going to be much easier, with your floor construction, to design and install a new hot water heat system. The choice of emitters is wide open -- baseboards, panel wall hung radiators, even over the top radiant floors as has been mentioned. The reason it will be much easier is that the only holes you will have to drill are for the pipes, which are small -- a 2 inch hole is ample for anything you will have, and most will be much smaller. This can be done with a core drill and is no problem, even if there is rebar in there (which there will be). Cutting holes for the ducting and registers for forced air heat would be a nightmare.

AlexPetron

hot rod_7 said:

As others mentioned all the water lines and traps under fixtures need to be winterized. Either blow them dry or add a non toxic RV antifreeze to the system.

Good job for someone experienced with winterization and geared up for the task.

Is Uni-Gard -50 Uni-Proof Anti-Freeze an example of such an acceptable antifreeze?

neilc

don't forget clothes washer, dish washer, and you need to run the drain pumps also,

fix the heat.

Jamie Hall

Did I miss something? Are you actually abandoning and closing the house, or just the heating system and keeping the place open otherwise?

If you are closing the place, then yes that anti-freeze you mention is acceptable. You will need to be very thorough in using it, though.

AlexPetron

Hi Jamie Hall,

Jamie Hall said:

Step 1 is going to be getting through the rest of this winter -- if you have the electrical capacity, yeah -- Home Depot or Lowe's and some electric baseboard. Cheap. The electricity costs will encourage further repair.

If you drain the water out of the radiant system and then shut it off -- and can keep the rest of the house warm (sort of) you can keep using the domestic water, of course -- except for one thing. What heats your hot water? If it is a separate water heater, you're fine. If it's the boiler... um, not so much. And you may have to get yourself a new hot water heater. You don't mention your current fuel -- but gas, electric, and oil water heaters all work well.

On the new system. It is going to be much easier, with your floor construction, to design and install a new hot water heat system. The choice of emitters is wide open -- baseboards, panel wall hung radiators, even over the top radiant floors as has been mentioned. The reason it will be much easier is that the only holes you will have to drill are for the pipes, which are small -- a 2 inch hole is ample for anything you will have, and most will be much smaller. This can be done with a core drill and is no problem, even if there is rebar in there (which there will be). Cutting holes for the ducting and registers for forced air heat would be a nightmare.

How do you mean that "The electricity costs will encourage further repair"?

The domestic hot water is fueled with a detached natural gas water heater. The current radiant system is likewise fueled with natural gas.

The ironic part of contemplating a new forced air system for this house is that partially-completed ducting already exists , as the builder was apparently considering installing central AC but didn't follow through. I know the existing ducting would have to be cleaned and expanded, but presumably this would diminish the costs involved with starting from scratch.

Gordy

Shut the boiler down. Shut the water off to the house. Drain the domestic water heater. Blow all plumbing, and heating lines out. Put anti freeze in waste traps. Come back in the spring.


Trying to heat all that concrete mass with electric heaters will break the bank.

kcopp

Is it possible to isolate the leaking loop? Other loops may be still solid... That would buy you time.