Is this my central heating drain valve?

[kkelly77]

Image attach fail!

 

[kkelly77]

Hi all,

I took a couple of photos of a valve located beside my oil boiler in my shed. Is the valve located beside the white pipe the drain valve for the central heating system? I need to drain the system partially to allow for fitting new valves and radiator upstairs. Thanks for the help.

K

 

[dontknowitall]

Couldn't be certain but it looks like it. Presumably you've not got one near an outside door or on a radiator as part of the lockshield valve?

 

[kkelly77]

No, definitely none on any of the radiators or near the boiler.

 

[tamz]

That is it. Just put a hose on it.
Don't "partially" drain the heating, fully drain it or you may have problems with air when you refill.

Also it you have any motorised valves on the system, manually open them when draining and filling.

 

[kkelly77]

That is it. Just put a hose on it.
Don't "partially" drain the heating, fully drain it or you may have problems with air when you refill.

Also it you have any motorised valves on the system, manually open them when draining and filling.

I have an expansion tank and an expansion vessel so my system is a semi sealed system. Is draining completely and then letting it refill the same procedure?

 

[Dotty]

exactly the same.

 

[kkelly77]

Well the new radiator is up and fitted but now the rads won't heat up. Now this could be because my Watchman on the oil tank is reading '0'. However, I set it up so that when it reads '0' there is still a small amount of oil left in tank.

After fitting the new rad I closed all the bleed valves on all radiators, turned them all off at the flow and return, then proceeded to let each one fill one by one starting with the rads downstairs. After this I bled the rads upstairs (which LOADS of air came out from). But when I turned the heating on, the rads didn't heat up. I went out to the boiler to see if was going but all I could hear was a sound coming from what I believe is a motor (see photo) attached.

Assuming there is still some oil left, any ideas why she ain't firing up? Thanks.

K

 

[electron]

Looks like that is the circulating pump.
Possibly still air locked somewhere in system.

 

[kkelly77]

Looks like that is the circulating pump.
Possibly still air locked somewhere in system.

Well the rads have all been bled. If there is still air in the system, shouldn't some of the rads heat up? TBH the tank is more than likely out of oil. I'll see if I can get it filled tomorrow and at least that possibility will be eliminated.

 

[tamz]

Is the boiler lighting up? Even if the system was empty the boiler would still fire up (not advisable) so check your oil if you think it may be near empty.

The "motor" in your photo is the pump. It will make a noise if there is air in it. Release the air by undoing the black nut on the front of it and pulling it forward slightly (don't worry, it wont come out).

 

[Dotty]

that is your circ pump. turn it all off, unscrew the black knob and gently pull it out. you should hear a load of air escaping. then go to your boiler stat (remember your boiler stat?) remove the black cap there and push in the wee little button.

you'll find that if your pumps full of air, you'll have no circulation and your boiler would've tripped out on high temp.

 

[kkelly77]

Is the boiler lighting up? Even if the system was empty the boiler would still fire up (not advisable) so check your oil if you think it may be near empty.

The "motor" in your photo is the pump. It will make a noise if there is air in it. Release the air by undoing the black nut on the front of it and pulling it forward slightly (don't worry, it wont come out).

No boiler isn't lighting up. Makes a distinct noise when it does. Just the pump humming away. You reckon if there is air in it, that could be the cause of the rads/boiler not working?

 

[tamz]

No. If the boiler won't light it won't heat. It has probably tripped out the overheat which as Croppie said is under the wee black cap.

Here, it is easier to show you

 

[kkelly77]

Brilliant! Thanks again for all the advice lads. Couldn't have done it without yiz. Photo attached of what it was all for.

Planning to fit TRV's on all rads soon enough so at least I'll know the procedure when I need to drain the CH again. Question on that actually, do you need to replace the return valve as well or can you just put a TRV on?

K

 

[tamz]

You can just do the Trv and leave the return but if you buy Danfoss combo sets you get a neat little chrome lockshield too.

Btw.
When refilling don't close the rads off at the valves. Leave them all open.

 

[kkelly77]

Well I unscrewed the nut on the circulation pump and there was no air. Just a bit of dirty water came out. I hit the reset switch on the boiler thermostat and it fired up first time

All the rads are heating up except the one in the hall. We had problems with this rad about 2 years ago. Called a plumber out who said he 'balanced the radiators' which solved the problem. How do I go about doing this as I could do without having to fork out for another plumber to do the 10 mins work which was done 2 years ago? Cheers.

K

UPDATE - I tried turning down the Return on all the hottest rads, And I tried turning off all the working rads and leaving the cold one on. It's still not heating up.

 

[Gray0689]

Who fitted the towel rail yourself?
Or a plumber?