Draining system

[jayc89]

I had our system boiler moved a few months back. I now want to drain the system to take a couple of radiators off and discovered the wally’s that moved the boiler removed the drain tap and haven’t fitted a new one, that I can see.

 

System has 3x 2 port valves, downstairs UFH, upstairs radiators and DWH. I’ve tried manually forcing those to open, opening the bleed nipple on the highest radiator (towel rail) and draining from the UFH manifold, but nothing’s coming out. The boiler has depressurised.

 

short of fitting a new drain tap, is there anything I can do today?

[Marvin]

Could manually open the pressure relief valve. Are the rads upstairs?

[jayc89]

2 minutes ago, Marvin said:

Could manually open the pressure relief valve. Are the rads upstairs?

 

Only PRV I can see is on the DWH cylinder. Yeah, rads and DWH upstairs, UFH downstairs. 

I expected draining from the UFH (lowest point) and letting air in at the highest point would do the trick, but I got little more than a dribble. 

[Marvin]

Pressure relief valve on the boiler?

 

I assume your going to eventually install a drain valve. If possible you could saw partly through the copper pipe where you want a drain point and fill buckets. Bit messy and often best to throw a cloth over the pipe to stop it squrting all over the place.

[Marvin]

Or turn both rad valves off and undo the nuts fixing the valves to the radiator, putting buckets or trays to catch the water. I usually use a sheet of plastic to protect carpets. When all water out you can usually remove the valves from the rad, but be careful not to spill any water by lifting one end up and draining into container. Shut the bleed valve, turn the radiator upside down and I usually put kitchen roll in the open radiator ends to stop drips before moving it out the way.

[jayc89]

Showing my plumbing naivety here. AFAIK, we have a standard S-plan set up for the upstairs rads and DWH, with the UFH pipework effectively bolted on. I believe it's teed off the boiler supplier prior to the rad and DWH 2 port valves. 

 

Would the water be able to flow through a turned off pump? We have the pump on the boiler which is the only pump used by the upstairs rads and DWH, but we also have a Grundfos pump before the UFH manifold. As I was trying to drain at the UFH, after that second pump, would it have allowed water to pass whilst being turned off? If I had a way of draining before the UFH pump/manifold, should it have worked?

[jayc89]

I have a downstairs rad, that I forgot about. (Old kitchen, not yet been renovated). I also have some 15mm copper pipe, olives and compression nuts. I'll see if I can drain from one of that radiator's legs instead, bypassing the UFH altogether.