How to fully drain lower radiators?

sixplex

Need to change a bunch of shut off valves on radiators that are below the main, wondering how to drain them all.

Do i need some sort of pump ? I was thinking of trying a shop vac first.

leonz

When you say the main, what are you referring to???

The normal way to do this is to shut the water feed off to the boiler first and open the vents on ALL the radiators after you have started draining the boiler.

Jamie Hall

A pump. Or a big bucket... keep in mind that if you have a shutoff valve on the inlet (I presume this is hot water) but not on the outlet, you are going to drain the whole system -- not just the radiator.

EdTheHeaterMan

Steam Rads should have some common piping at the bottom of the condensate return that leads back the the boiler wet return. All those radiators should be above the water line even if they are below the steam main. But I'm guessing that is not the case

On a water system toy have to think like water. You need to let air in so the water can get out.
1. Open the boiler drain and let all the water out until it is empty.
2. Now check that all the radiators above the main are really empty.
3. If there are flow control valves (Flo-Check®) valves that are closed, you will need to open than so the water held by the check valve can drain back to the boiler.
4. Now look at the radiators that may be piped down from the main. Obviously the water in those radiators cannot drain up to the main then out the boiler drain. So you will look at each one individually and see where each radiator can be opened. Perhaps at the union connection.
5. Place a container under the connection, open the connection and allow the water to collect in the container
6. Pump or otherwise remove the water from the container as that radiator drains completely.
7. Repeat 4, 5 and 6 on each additional radiator until all radiators are empty.

Another way is to use a reverse gravity machine that will invert the home so all the bottom water will go up. see attached files

sixplex

These are not steam rads, hot water rads. I want to drain the hole system. Both supply and return line on the basement baseboard rads go UP to the "main", it's monoflow system. So i don't see how water would leave if i drain the hole system. Draining each of the baseboard rads individually isn't ideal.

Jamie Hall

Well, you are right -- the water won't come out of those low radiators when you drain the rest of the system. There is only one way to drain them, and that is to disconnect each one from its inlet (or outlet, whichever is lower) and let the water run out. It may not be ideal, but it's the only way it's going to happen.

Of course as soon as you disconnect one of those radiators, the rest of the system will drain, too -- so it might be really smart to drain as much of the system as you can to somewhere else more convenient before you start.

109A_5

Hello @sixplex,

I think I would drain the boiler and most of the system, that way you get the majority of the water out. Then either remove the old valve from the valve body with a bucket underneath. Or if you want a more slower controlled drain just drill a 1/8" hole (or what ever size you like) in the lower part of the valve body of the valve that's going to be replaced. If valve replacement is going to happen often you may want to add a drain valve too.

JimP

The idea to drill a hole is interesting. In this case a shop vac might work good if some are too low (like baseboard radiators)to get much of a pan under.

EdTheHeaterMan

JimP said:

The idea to drill a hole is interesting. In this case a shop vac might work good if some are too low (like baseboard radiators)to get much of a pan under.

If the shop vac has enough capacity to hold all the water... What happens when the shop vac gets full and stops removing water? How are you going to stop the water from flowing while you empty the shop vac?

There are some very shallow pans like a large cookie sheet that can be placed under the baseboard radiators where you choose to cut them. Water can be pumped from that shallow pan to a drain or outside.

Just something to think about.

A temporary drain can be made with a piercing valve like the valves used with ice makers. That will get you a hole in the pipe with a shut off valve. It may take longer but you can control it.

Once everything is empty, then make arrangements for easier service in the future.

JimP

I tried the shop vac idea today. It worked fantastic! I had to empty some CI baseboard to add another section in a room with a wall that wasn’t flat and is 10’ below the supply and return. I cut the pipe and added a valve ( thinking I wouldn’t need to drain the existing installation). When I realized that I’d need to adjust for the wall I didn’t have room for the valve I opened the valve and the water flowed into a container about 1” deep where the shop vac collected it. Worked great, in fact at the end I was able to suck out water. I could hear the suction through the open air vents! Thank you 109A 5 for the great idea!

jumper

I always carried a water powered eductor. Sometimes one can apply suction and then avoid having to drain. For big draining jobs a compressor + air powered venturi eductor into landscaping or parking lot.

sixplex

I tried a shop vac, it works if it's connected to the rads supply or return, but not nearly enough power to to it from the boiler room.

Best idea thus far is to syphon the water out of the rad by sticking a tube into the 1/8 bleeder hole