Leaky Radiator Drain Valves - One Zone Hot Water System


Old 11-26-15, 08:29 PM
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Leaky Radiator Drain Valves - One Zone Hot Water System

So there are 6 radiator on each of the two floors of my house. Each of the 6 bottom floor radiators have a boiler drain valve(see pic below), the top radiators are connected to a matching bottom radiator and do not have drain valves.
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Anyway we just bought the house and haven't fired up the system yet. The problem was 4/6 drain valves had a slow leak, 2 or 3 drops an hour. I was able to stop the leaks by screwing on a brass hose cap on the valves. All but one now seem to have stopped leaking, the one seems to be leaking from the stem, and leaks very slowly, maybe 3 drops a day. Anyway not sure what I should do... since I am afraid once the system is turned on and pressurized all of them will start leaking... should I replace all the valves with new valves? Is it okay for me to drain the whole system so that I can do that? I heard its not so good to drain the system as the new fresh water will introduce oxygen to the system - if I do drain the system should I add some sort of additive? Is there a reason that a valve is needed for the radiators?? Instead of replacing the valves, should I just replace it with a plug?

Sorry for all the questions; I am a newbie and kind of at a loss as to what is the best course of action...
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Old 11-26-15, 08:58 PM
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Drain valves are probably just to easily drain the upper rads from the bottom rads..

The caps on the valves are fine... The one leaking from the stem just needs to packing nut tightened is all...

I would not replace the valves unless you have too..

Can you take pics of the boiler from several angles?
Old 11-27-15, 06:52 AM
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Drains (vents) for a hot water heating system are usually located at the highest point in the system, In your case it would be the upstairs radiators. My guess is the upstairs radiators were added later, hence the reason for the drains on the first floor.
When you state the upper floor radiators are connected to a matching bottom floor radiator, is it one pipe (feed) or 2 pipes (feed and return)? What I can't determine is if the radiators on each floor are in series or parallel. Can you tell?
On most hot water installations, there is plumbing to isolate each zone. A garden hose is connected to the zone and the pressurized water supply is used for force the air from the zone. All the radiators in the zone are in series.
Do you have 6 zones here. A picture showing the feed from the furnace to the first floor radiators would be helpful.
Old 11-28-15, 08:51 PM
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I believe it is all one zone, I took some more pictures as you guys suggested:
Below are pictures of the Hot Water Boiler
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Below are picture of the bottom floor Radiator, if you look closer you can see the feed/return:
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Below are pictures of the radiator on top floor:
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