How can I drain a specific heating zone?

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Old 09-03-20, 06:50 PM
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How can I drain a specific heating zone?

hi all. I have baseboard heat in the house, and need to relocate a stretch of the baseboard to complete some kitchen renovations. I have three zones; one of them is going to the hot water tank, while the other two go to two separate floors.

I see three return valves on the zones, and one going back to the boiler. I'm not sure what the sequence here should be. I think I need to close the boiler return, and the zone which I want to drain, and then just turn on the spigot upstream of the boiler return. But I'm really not sure.
Also, do I need to refill the boiler after I drain the zone?

Please see attached images. The yellow handle valves are the zone return valves, and the white handle one is the boiler return. I need to drain the 2nd zone (middle yellow handle)





 
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Old 09-04-20, 08:44 AM
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If you have isolation valves on both the supply and return and a spigot on each individual zone for bleeding you do not have to drain the boiler. You can shut the valves off on the zone you want to drain and open the spigot above the isolation valve on the return and that zone and only that zone will drain and that will allow you to complete your work.

Your pics only show your supply header with the pumps. It does not show where your return lines come back to the boiler. You should have 3 return lines just like your supply lines. You should have isolation valves on each one plus a spigot to bleed each zone.

That white valve you are showing is on your main boiler return. If that's the way your system is piped and that is your only shutoff on the return side then you will be draining your whole system every time you work on anything which makes much more work as each zone must be bled after the work is completed.

If you could post pics of where your return lines from each zone come back it would be helpful.

Hope this helps a little.
 
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Old 09-04-20, 02:37 PM
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does this show you anything useful? sorry, I am completely clueless when it comes to heating/cooling systems. I took a panorama pic which shows everything. there aren't any other valves aside from what you see here. if the whole system has to be drained, that'd be fine, if I knew whether or not any of the components need to be resupplied with water before turning everything back on

 

Last edited by PJmax; 09-04-20 at 09:46 PM. Reason: labeled picture
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Old 09-04-20, 07:14 PM
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If in reality these are the only valves that you have you may want to call in a pro to make sure you're not missing anything, especially where you have no experience because with what you are showing you will also not have any domestic hot water while your boiler is down.

What you must do is to shut the WHITE VALVE off on the return and also the WHITE VALVE on the 1/2" pipe with the GREEN FEED VAVLE on it and open the RED drain valve and only let out as much as you need to, to work on the system.

You will have to refill the boiler by opening that WHITE VALVE on the 1/2" line and the bleed the air from the zones before you turn the power back on to the boiler.

With no experience with boilers I don't recommend trying this without some instruction help from someone who has some knowledge of these systems.

Just my opinion.
 
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Old 09-04-20, 09:45 PM
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That looks like a fairly new installation but it's missing some typically installed valves. I labeled the picture as it aids in discussion. I'd expect to see a shutoff valve at the G to F connection.

What are the A and B pipes for ?
 
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Old 09-05-20, 12:54 AM
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@spott, thank you so much! that is immensely helpful! I will try and get more familiar with this before attempting it. I am definitely also considering paying the company who did this install for an hour of their time, to walk me through the process; if they're open to it.

@PJMax, you nailed it. This was just installed yesterday to replace a 20ish year old boiler. To answer your question, pipe A is running from circulator #1 (starting from closest to pipes A and B), down into the slab. I assume that is supplying the hot water to the baseboards on the first floor. Pipe B comes out of the slab, and meets up with the pipe F; I am guessing that pipe B is the return for pipe A.

You mentioned that you would expect some other closing valves in certain places -- would you recommend that I call the installation company and have them put those in?
 
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Old 09-06-20, 10:40 AM
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If I am understanding you correctly A is connected to C which we'll call zone #1 abd B is the return connected to F which is the main return to the boiler. That leaves 2 zones unacounted for. D & E are the 2 supply's left. Pipe labeled G I'm guessing is the return from your HOT WATER tank. Your pics do not show which pipe is your supply, either D or E. The last zone return is not shown at all.

You should have isolation valves and drain spigots on all return lines such as pipe G and pipe B and the return not shown. This is to be able to isolate any zone without interupting the rest of the system. For example if you had an isolation valve and spigot (draw off) on pipe B you could work on that zone while the rest of the system operated normally and you would have hot water and could work at your leisure. If in the winter something happened to your hot water or one of the zones you could isolate that zone and the other 2 zones would still work nomally.

Thank you Pete for the labels. It made it so much easier to explain and yes, you should have those missing valves and drains installed.
 
 

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