Help!! Draining CH sys - stopped draining... airlock???

[garrymum]

Hi guys

Further to my post of this morning I decided to drain the CH system to remove a towel rad (floor fed). Also bought some Sentinel X400 to give it a clean. This is what I have done:-

1. Turned off boiler
2. Tied up the ball cock in the F&E to stop water
3. Connected hose at lowest rad and started draining
4. Opened upstairs bleed valves

All but 1 downstairs rad are still full and there is no more water coming from the drain hose.

The F&E tank is also not completely empty, sits just above the bottom pipe.

Guessing there is an airlock somewhere? Any ideas on how to totally drain the system.

Help!!!!

 

[Blasphemous]

Have you opened the Bleed Valves on the down stairs rads?

 

[garrymum]

Have you opened the Bleed Valves on the down stairs rads?

I have on the 1 rad which I am draining from, all the rest are full of water. When I open them water spurts out

 

[garrymum]

anyone

 

[Azazel]

it could be that each of the downstairs radiators are on their own 'drop'. If so you will have to drain each rad/drop individually, hopefully the original installer would have put drain off points for you to use.

Not sure why the water is still just sitting above the level of the cold feed pipe in the f+e tank. Have you got any motorised valves? If so it helps when filling/draining a central heating system to have these in the manually open position.

hope that helps

 

[garrymum]

it could be that each of the downstairs radiators are on their own 'drop'. If so you will have to drain each rad/drop individually, hopefully the original installer would have put drain off points for you to use.

Not sure why the water is still just sitting above the level of the cold feed pipe in the f+e tank. Have you got any motorised valves? If so it helps when filling/draining a central heating system to have these in the manually open position.

hope that helps

Hi, thanks for the reply.

I have drained the system before months ago and didn't have any problems, the F&E tank emptied that time.

What I have done since posting is connect a hose to a tap and put the other end in the F&E bottom exit pipe. All this did was fill up the F&E tank.

Then I put the hose on bottom rad and reverse filled the system until all rads were full and it started to fill the f&e tank. I then tried draining again and all the upstairs rads have drained. Bottom ones (apart from the one I am draining from) are all fall and the f&e tank is half full. I have put the motorised valve to the manual position but that hasn't helped.

 

[garrymum]

Right, turns out the cowboy plumbers who started re-doing our ensuite (before we sacked them as there work was crap and the damaged our new units) turned off the gate valve which is on the down pipe from the f&e. This is the reason the f&e tank was not draining.

Downstairs still didn't drain, the only downstairs rad to drain was the one I was draining from. Seems strange as one of the full rads is one which I had to replace a broken valve last year - so obviously drained ok last year).

Anyway, Sentinel in, re-filled ok, took about 30 mins to get the boiler to work properly as it kept banging and locking out - guessing due to air in the system.

Also the cowboys have opened EVERY LSV (13 rads) to fully open so expect a post tomorrow about balancing the system.

Anyway, my kebab has just landed so I'm off for a well earned kebab and beer!

 

[garrymum]

Has anyone any thoughts on why the downstairs rad did't drain?

 

[RigidRaider]

We have one rad (in the bathroom) which is on the boiler HW circuit. Could that be the answer?

 

[poolebybirth]

I don't know what your system is, but having a gate valve on the F & E cold feed is asking for trouble-it is DANGEROUS!!!!!

 

[Rico99]

garrymum,

As previoulsy stated it sounds as though each of the downstairs rads is on ints own drop.

Do you have drain offs on each of the downstairs rads.

Did you drain off from the one on the rad you changed previously.

Rico

 

[garrymum]

garrymum,
Do you have drain offs on each of the downstairs rads.
Rico

Yes. Does this mean all downstairs rads need draining individually?

garrymum,
Did you drain off from the one on the rad you changed previously.
Rico

No, I drained from the one in the kitchen as I did last night. This allowed me to remove the rad valve from another downstairs rad (which did not drain last night)

 

[pompeyal]

Sounds like a bit of a nightmare to me, but a tip for when topping up to reduce or eliminate the banging, turn off all the rad valve on both sides allow the system to top up and purge the pump, turn off the gas to the boiler and start up the system to run the pump, this will force the water all round the system without picking up any air for any rad, once you are happy that the pipework is full turn off the system open each rad both ends and bleed the rads, the gas back on, and restart the system....