65+ years old Hot Water Radiant Floor - Still Working - But For How Long?

NY2KW

We bought our house 3 years ago. It’s an 85+ years farmhouse heated with hot water baseboard (10 year old boiler) and works very well even in minus degree weather we are now experiencing. However a large family room addition built on slab in 1950 is heated with hydronic radiant system under ceramic tile. This room is 25’ w x 40’ l x 20’ h and has a very large solid fieldstone fireplace thermal mass going from floor to ceiling and the exterior stone is fully exposed (another problem). I am worried about the remaining lifespan of the radiant system and my options to keep it going as long as possible. The boiler is topped off with well water that is on the low side of neutral pH (7.1) with mild hardness. To the best of my knowledge, no additives have been used in the boiler system – at least for the past 20+ years. The radiant floor is fed by the same boiler as the baseboards but has a dedicated 1-1/4” copper line with a mixer (temp kept around 120F) and dedicated circ pump. The manifold is just four (4) parallel 1/2 “ copper pipes (picture attached) without any balancing valves going into family room subfloor (can be seen in my service basement) and the returns are similarly piped with 1/2 “ copper but includes a drain valve for each of the 4 lines. The floor tiles in the family room tonight are about 75-77F with outside temp minus 3F and the room is noticeably cooler but air temp is staying at 60F. What can I do for routine maintenance to delay failure of the copper pipe under the floor? I guess pipe failure but it has worked well for 65+ years. Any advice appreciated.

Gordy

It could last another 65 years. I would say you are doing all you can. Usually failures are from external causes. High content fly ash concrete, acidic soils tube is in contact with.

Just have a plan for when, or if it fails. Do an over the top type of radiant.

hot_rod

It's great to see an old system like that still doing a good job.

I've found that keeping any water away from the soil below is key to old copper or iron systems. The ones I have worked on tend to fail in the bathroom areas where a leak from a drain gets the subsoil wet then corrodes the tube from outside in.

Same with water getting underneath from poor drainage or guttering around the home, wet soil will really wick away the heat also.

I'd let the sleeping dog lie!

AnthraciteEnergetics

Neat! I've never seen one of these in real life... Is it normally a continuous soft copper loop (or at least lacking ells), or are there fittings (ells or 180 return bends) under there?

Gordy

Soft copper 180 bends. Usually.

jumper

If you're really worried you need water meters at each end to know there's no leaks. Otherwise take HotRod's advice about sleeping dogs.