How to drain a zone on System 2000 EK-1 boiler

atulc · 08-30-2012, 11:04 PM

In order to replace a baseboard radiator, I need to drain out the zone feeding the radiator. My heating system is System 2000 EK-1. In the attached picture, you can see three zones each with its zone valve, shutoff valves, and drains. The zone I need to drain is the middle one.

In the picture, toward the front is the hot water feed line from the boiler feeding into the three zone valves, each followed by a shutoff valve. Towards the rear, you see the three return lines with drain valves and shutoff valves.

Can someone help me with step-by-step instructions for draining one zone on this boiler? Once I've replaced the radiator, how would I refill and purge the zone? Thanks!

techpappy · 08-30-2012, 11:34 PM

Close all the main valves except the top middle one which feeds the zone you want to drain then attach a short section of garden hose to the drain and direct into a bucket or drain (do not use longer than 10 foot hose..could take forever to drain) Then open drain line. It will gush out at first but will then just trickle out once the presure is dissipated in the zone. The, to aid drainage, crack open a fitting at the zine rad to let air into the zone..that will provide air which allows the water todrain freely. If you have to refill,then, leave fill line to boiler "on" and open the valve from the boiler to the zone keeping the rad bleed scvrew open or keeping the connection open until water bleeds out with no air in it then tighten back up. After this is done you can then open remaining valves to the boiler and resume operation. This procedure should prevent air from getting into other zones and prevent any air locks from occurring. Hope this helps. If there is more than one rad in the zone you may have to open the bleed valves on all the rads in that zone during the refilling process to make sure there no air in them

Forgot to mention..you do not have to drain the entire zone. Just drain until water is below bottom of lowest rad in the zone,,you can check this by slightly opening the connection/union at bottom of rad and place pan under it until water stops draining from it. Then shut drain valve at boiler. This will minimize air in system and amount of water to refill. Also put towel under rad to prevent staining. Water will likely be somewhat dirty.

DON'T FORGET TO SHUT OFF POWER TO BOILER WHILE YOU ARE DOING THIS!

atulc · 08-31-2012, 01:15 AM

Techpappy - thanks. Just to be absolutely sure, I am rephrasing your instructions as I understand them. Please confirm whether this is right.

1) Turn off power and gas supply to the boiler.
2) Shut off water supply to the boiler (close the fill line valve).
3) Close the valves in the feed lines for the other two zones while leaving the valve for the zone I'm working on open.
4) Connect a garden hose from the drain valve for this zone and direct into a bucket.
5) Open the drain valve for this zone.
6) Crack open a fitting at the zone radiator to assist in drainage.

Should I also close off the valves on the return lines for the other two zones?

If I want to have the boiler working while keeping zone 2 out of service for some time, can I, after draining zone 2, close off the feed and return valves on this zone while leaving all other valves open?

techpappy · 08-31-2012, 10:16 AM

Yes , you got it right. Of course pretty much just reverse for refilling.

Shut off ALL valves except for the supply and drain valve to the zone you are draining..i.e., close off the valve to the boiler (at bottom back) for the zone you are draining as well as the others. This prevents excess water escaping form boiler.
AND yes again..as long as your valves are holding, which they appear as they will, then just keep the supply and return valves closed to the zone you want to keep off. I am assuming that your expansion/cushion tank is not connected to that zone. If it is then you would not be able to do so.

When, eventually refilling , just leave the union slightly opened at the rad and then partially open the valve from the boiler to the zone. Leave open until water coming from fitting..tighten fitting making sure to leave bleed vent open..eventually all air should escape fdrom bleed vent until clear water appears, i.e., water without air still spurting out with it..you should hold a pan or plastic bottle or something to contain water until it comes out in a steady stream without air bubbles.

Just follow the steps slowly..double checking each move as you go and you should be fine...OH ..and don't forget to put some teflon tape on any threaded joints when installing new piping

CHEERS Techpappy