Advice on draining heating zone needed


  #1  
Old 03-26-23, 01:17 PM
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Advice on draining heating zone needed

Hello-
I am working on moving a baseboard radiator and need know how to drain the zone and then properly purge it back out. What's got me confused is my radiators don't have any type of bleed valves. How do I introduce air to thoroughly drain the system? Besides cutting in and just hoping I don't make too big a mess. I am going to sweat a few fittings so will need to drain thoroughly.

See the pictures below. I assume I should close off the zone at both ends and open the drain at the top left of the picture below. But I don't know how to open an air valve somewhere to let the water out.

The zone I need to drain is on the far left. It has a drain valve above the shutoff which for some reason does not have hose threads. The shutoff below the T is connected to the zone I want to drain and another zone. The next picture shows shut off valves for that other zone.

Below are the zone valves. The one farthest left is for the zone I am working on, and there is a shut off valve after it.
 

Last edited by PJmax; 03-28-23 at 05:52 PM. Reason: resized pics/labeled pic
  #2  
Old 03-26-23, 03:12 PM
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As much as possible, isolate the section of pipe that you need to cut. It needs to be able to flow to a drain. If you do not have bleeder air valves at the baseboard, air will be introduced when you cut the pipe. You only need to drain water to just below the level you are working on. No need to drain the first floor if you are working on the second. No need to drain the boiler if you are working at the first floor. If the drain is open and there is no water above, the cut will introduce air and there should be little or no water coming through the cut. Cut the pipe from top to bottom.
 
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Old 03-28-23, 03:22 PM
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I'll just add that it really helps to have a wet vac close by when you're making the cut!
 
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Old 03-28-23, 06:06 PM
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Make sure main water is turned off.
Make sure the thermostats are off - no call for heat.
Shut the boiler off.
Close Ra(return) and open Pa(purge). It may be easier to slide a piece a piece of hose on that pipe
as there may be too much water for a bucket to hold.

The zone valves are on the S (supply) side.
Close S valve.
Closing that valve near the zone valve will isolate that zone from the boiler.

After you get done with the repair. Leave boiler off and thermostats not calling for heat.
Close Pa (purge valve)
Turn the water supply back on.
Open S valve.
Set the zone you worked on to a call for heat. If your zone valves are powered off the boiler....
you may need to open that zone valve manually. Open the zone valve.... and re-open shut-off valve.
Check for leaks.
Open Pa slightly to purge air from the that zone.
When all the air is out..... the system should be purged and can go back into normal service.

Cutting the zone open will allow the water to leave thru Pa.
A shop vac is a great idea..... along with a few sacrificial towels.
 
  #5  
Old 03-29-23, 08:47 AM
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Gropp: But I don't know how to open an air valve somewhere to let the water
Here is easy, long term heating system venting solution.

Install $12 Watts auto vents at high points of each zone, Are very reliable, easily opened for service. Has black knob on Watts to manually check, confirm venting or turn off. https://www.supplyhouse.com/Watts-05...Vent-3679000-p

Below are items to install on baseboard lines, Watts auto vents with ” male fitting.
https://www.supplyhouse.com/Elkhart-...-Tee-Lead-Free
https://www.lowes.com/pd/B-K-1-4-in-...ing/1000505705

Gropp: Before starting make depressurization and service easier installing tee with drain faucet and shut valve on line to expansion tank. Tanks are best located where easy to service/remove with ” nipple at bottom. With nipple on top debris in water collects on top of bladder shorting life.
 

Last edited by doughess; 03-29-23 at 09:08 AM.
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Old 03-29-23, 02:49 PM
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Thanks for all the advice. The labelled diagram is very helpful. I will get some towels and a shop vac ready
 
  #7  
Old 03-30-23, 08:47 AM
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Venting Baseboards Effectively, Long Term, Low Cost

For easy way to effectively vent baseboard heating systems see Installation on Page 2. Fig 1 & Fig 2 .

http://s3.pexsupply.com/manuals/1322..._PROD_FILE.pdf

In Fig 2 is basic theory of air scoops. ”. 2.5 times pipe ID * ID = Inside Dimensions
As water flows thru line, if diameter increases, pressure temporarily drops slightly, facilitating air bubble release to high point of larger diameter where can be vented.
 

Last edited by doughess; 03-30-23 at 09:38 AM.
 

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