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secutanudu 09-27-2010 01:50 PM

Changing valve near boiler loop
 
I have an old stop & waste gate valve that's leaking. It's on the line that feeds fresh water into my boiler loop.

I will obviously need to shut the house water at the meter, cut out the old valve, and drain the pipe that comes from the meter.

Do I need to also let some water out of the boiler to take the pressure off the system so the water from the boiler loop doesn't come pouring out of the pipe on the other side? Or should there be a check valve preventing water from backing out of the boiler loop?

If I do have to let the pressure out of my boiler, should I be concerned with turning it back on? How do I get the air out of the system that I just let in? Thanks.

Daniel Holzman 09-27-2010 07:56 PM

I replaced a similar valve two weeks ago. I am on a well, so it was easy to turn off the well, and drain the boiler down below the level of the valve. Sounds like you are on city water, so you need to close the main valve as you indicated, and drain the boiler down to zero pressure. By the way, shut off the boiler before you do anything, if it is not off for the summer already. While you are at it, make sure there is a backflow prevention valve in your cold water makeup feed, mine was an old system and did not have one.

secutanudu 09-28-2010 07:51 AM

There is a pressure regulator feeding the boiler (just downstream of this valve)...do those sometimes have backflow prevention built in? I'll try to take a picture tonight. If not...what type of backflow do you recommend? Just a simple check valve or something more rugged?

The valve I plan to change is about 1-2 feet of 1/2" copper away from the boiler, not on the boiler itself. I assume I shouldn't have to drain much water to get the pressure off. I mean if the boiler is cold, how much pressure is on it? 10-20 pounds?

I also plan to replace the air relief valve (what's that thing called), because I've seen water coming out of it. I assume that means it's gone bad? Is there anything special I need to do to let the air out of the system when I start it, or will this air valve do the trick?

The boiler's already off for summer, and I should have done this a month ago instead of now, when I'll probably be needing heat soon!

Daniel Holzman 09-28-2010 07:58 AM

I had a similar arrangement, with a Watts boiler feed valve downstream of the gate valve. Watts makes two types of boiler feed valves (at least), one of which has the backflow preventer built in, one does not. I had the type that did not have the backflow preventer, which was common when the system was installed (early 1960's). The boiler feed valve was so gunked up with crud that it had stopped functioning, so I replaced it, and added a Watts backflow preventer in the system along with the shut off valve. The feed valve cost about $40, the backflow preventer was about $30, and I had to sweat some copper.

I assume the air relief valve you are talking about is the air bleed valve, not the pressure relief valve. I have a pair of those automatic air bleed valves on my boiler, so far as I can tell they are designed to automatically release air from the system, and need no attention unless of course they go bad, as yours appear to have done. And the only pressure in your boiler will come from the house pressure, since your boiler is off, so shutting off the main house valve and draining a small amount of water from the boiler should reduce the boiler pressure to near zero.

secutanudu 09-28-2010 08:20 AM

I see a ton of different types of Watts check valves. Is a simple swing check valve all I need? Is a "feed valve" simply a pressure regulator? The one existing on my system appears to work, I think. So all I really need to do is add backflow prevention and change the leaky valve.

I don't mind sweating some copper.

secutanudu 09-29-2010 09:28 AM

So I soldered in the new valve last night...no leaks, then I checked this morning and there's a slow leak out of the ball valve itself.Not on the solder joints. Like right where the handle attaches to the body.

Did I do something wrong (overheat maybe?) or is this a defective valve?

47_47 09-29-2010 01:15 PM

Remove the nut and handle. You should be able to snug up on the packing nut.

secutanudu 09-29-2010 01:20 PM

Thanks - I'll give that a shot tonight before replacing the valve with the replacement I just bought :)

Watts vs. Apollo....thoughts?

47_47 09-29-2010 01:30 PM

Aways used Watts.

del schisler 09-29-2010 01:39 PM

Quote:

Originally Posted by secutanudu (Post 508717)
So I soldered in the new valve last night...no leaks, then I checked this morning and there's a slow leak out of the ball valve itself.Not on the solder joints. Like right where the handle attaches to the body.

Did I do something wrong (overheat maybe?) or is this a defective valve?

tighen the nut under the handle. That should do it .

secutanudu 09-29-2010 09:50 PM

Packing nut appears to have fixed it. I'll know for sure in the morning. Thanks everyone.


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