Re packing hand valves

FranklinD

This summer is already getting away from me. On my list of things to do, I have to repack my hand valves and replumb my near-boiler piping to add a boiler bypass and stubs for a future indirect (which will be added whenever my current water heater goes kerplooey.

What I'm wondering is, how long can I leave the system drained without significant rust/oxidation formation (that may cause issues)?

My system is hot water with cast iron stand-up column radiators, steel pipe (mostly 1" and 3/4"), and copper for near boiler piping.

I know the de-oxygenated water currently in the system (filled last year) is protecting the interior of the pipes, and that as soon as I drain it, the nasties will start to grow.

If I drain it but keep it as sealed as possible, will that help? Otherwise I will take a day or two off work and try to hammer it all out in 24-48 hours.

Thanks in advance for any thoughts on this subject. Perhaps I'm worried about nothing in the long run. Better safe than sorry though.

Happy Fourth to you all!

nicholas bonham-carter

You won't need to drain the system for the valve re packing-just for the repiping.
Can you make up the piping before you drain the system?--NBC

FranklinD

Unfortunately I won't be able to prefab the boiler piping. I have to reuse the circulator, air separator, reducing valve, and so on.

It works as-is, I just want to rearrange components so that I am 'pumping away' and also to add a boiler bypass. Right now my system temps in the winter rarely top 150*, and that temp is only when it's -10 to -20*f outside. I've also been considering a Danfoss Thermic Valve for boiler protection, though my boiler is rated for 110* return water. In the shoulder seasons, though, I rarely even see 90* return water.

I'll try to post some pictures later of what I'm working with. As mentioned in a previous thread, I'm on my own at this point with the system (installer issues). Which is okay. I've been practicing my soldering on larger pipe (though I'm more comfortable with threaded black pipe, but oh well) and I have a mechanical background. I do a lot of 'plumbing' work, but usually it's on heavy equipment hydraulics and automotive cooling and air conditioning systems.

I was concerned that water would be 'shooting out' when I take off the packing nut on the valves...a trickle I can handle. I have about 15 feet of graphite impregnated packing rope (?) to use, and recently found a box full of old wooden valve knobs that match the few left in the house. Granted, I also have a box of 6 new 3/4" hot water angle stop valves that I bought online. But I've read that if I remove the old valve, the pipe may 'sproing' out of position due to settling. So I'll try the repacking first.

RobG

The biggest pain in valve replacement is the fact that the spud has to be replaced as well. Replace the packing if possible.

FranklinD

Agreed. Fortunately I have a spud wrench and all the new valves came with new spuds (the correct size for my rads). I got the wrench and a valve for a bathroom radiator I added last year.

All things considered, I'd rather stick with what's already there. The old valves are the barrel style for old gravity systems, with a large opening on one side of the barrel and a bleed hole 180 degrees opposite.

All the replacements I have are like globe valves (though they still have a bleed passage drilled through the seats). I was concerned they might have significantly higher pressure drop than the huge openings in the 'barrel' style valves.

JUGHNE

Steam cast iron rads and steel piping are exposed to air on almost every heating cycle. (The same materials as in your converted gravity system.) As most people here could attest that there are many 100 Year plus old systems that are still intact. My church has a 1911 cornerstone and still has the original piping and rads. On boiler # 3 or 4 maybe.

Many steel boilers (steam & hot water) get opened up for insurance inspection every one or 2 years and might stay open & empty for weeks ready for the traveling inspector
......just my observations.

The spud wrench works great for installing new....and sometimes for removing old. The chisel and saw blade method in not that difficult to do.

Of course after refill the water is brought up to at least 180.

FranklinD

Sheesh. Now why the heck didn't I think of that? Makes sense to me. I'll probably just leave it drained for a week or so while I do everything I need to do. Looking forward to this winter to try out the planned changes. Summer is okay, but fall is my favorite season by far.

JUGHNE

I'm sure you thought of this, but it is not always an obvious need.
So here goes; put isolation valves on all the supply & return pipes near the boiler. I have had to drain entire system to change PRV or pump. Some old gravity systems take a long time to fill and longer to purge of air.
Also in the future with those valves in place you would introduce less new water/oxygen into the system for any boiler items that need to be replaced/repaired.
As for pressure drop thru new valves, the old ones probably enjoyed the large passages for gravity flow. But you now have a pump to overcome the pipe friction that gravity had to deal with.
Take your time to think everything out. Those isolation valves will let you change near boiler piping easy and fast.
Also I have used the isolation valves to balance a system, (fully open for more flow on the Northwest floors and cut back a little on the Southeast floors.
One church Rectory I maintain needs no heat on the second floor but for maybe 3 days a year. With those valves closed the by-pass port provides more heat than actually needed. So as to not overheat these rooms, those rads do not get all the air bled from them. I check them in real cold weather to be sure water is moving thru the rad, to prevent freezing. (Could probably put a quilt over them for the same effect.) I got this idea from reading Dan's books about gravity systems with no expansion tanks. The dead men used the air in unbled rads for the expansion of heated water.
Yes, I tell myself don't get in a hurry......got all summer.......Damn, all of a sudden we need heat!! The snow is flying and there is ice on the road!