Vaillant TURBOmax Plus - filling?

I have been sent this picture of a Vaillant boiler where the pressure needle is down at the bottom. I advised my friend that it (obviously, doh!) needs re-filling and I superciliously (super-silly?) told my friend there should be something obvious on the underside... but - sadly - this picture has kinda proven me wrong, so now I'm here feeling sheepish.



I watched some YouTube videos - they indicated some models would have 1 valve that you could turn with a screwdriver... whereas some models had a pair of valves with plastic keys that you would turn in tandem to re-fill.

I am struggling to see either option here. Can more experienced eyes help me out - this shouldn't be hard, should it? I am told there is no plastic key in sight. The only things I think I see are the two sockets at the top-right... in-line with each other (horizontally) but I'm not sure what kind of screw goes in there.

All the other valves in sight already look open to me, am I wrong?

A search of existing threads brought this up... it looks very promising, right?

https://www.diynot.com/diy/threads/how-to-refill-vaillant-turbomax-plus.36483/

Still not sure if they look like normal screws to turn, though...

The boiler comes with a key that fits these 2 valves. Turn both 90° anticlockwise to fill boiler, then turn both back. The slot indicates the valve position, front to back closed, left to right open. They are often stiff if they haven't been operated in a long time. Some radiator bleed keys will fit the square fitting.

Thanks all.

Hiya again... first things first - I went around to see it. The needle was down fully. I was able to use a normal flat-bladed screwdriver to turn both of the valves 90 degrees. There was no special key that I could see (shame).

The boiler started to make the noise you'd expect when it's filling. However, this is where I (at least) think it got strange. The needle did not move at all for quite some time. Eventually the noise being made by the filling loop somehow changed... rather than sounding like water it started to sound more like a hissing, like air was going through... weird. But I left the two valves fully open and the needle started to go up - but very, very, very slowly.

When I've done this in the past on, say, an Ideal Logic+, the refill operation would show the arrow changing position over a period of seconds. You'd open it up and it'd be done before you knew it.

With this I must have been there for about 10 minutes - maybe 15 (I'm not exaggerating). I was astounded. Eventually the needle got to the middle of the green area - so about 1.2 bar I'd say, and I pressed the reset button and everything seemed fine.

Is there anything dodgy here, according to anyone's experience?

Last thing I noticed... I expected the red (leftmost) light to be on, but it was not. I also expected a F code to be displayed on the LCD, but it was not. When I left the boiler was doing its thing, the radiators were heating-up and the LCD display (when you press the i button) said S.04 (which I think is "calling for heat").

I've never experienced a refill take that amount of time... it's not something I do all the time, but this one seemed strange to me.

The refill time on mine takes a while too, though not that long, but I have high water pressure. If it has suddenly lost all that water there may be a leak, or the expansion vessel and pressure relief valve may require servicing/replacement. Also check the pressure relief pipe that goes outside, for drips, or the pressure rising excessively on the pressure gauge. The hissing was probably the automatic air vent inside the boiler, as the water filling will replace the air in the system. The radiators may need bleeding too.

If you have added a lot of water, the system may need corrosion inhibitor adding to it, contact a registered heating engineer. An engineer will also need to be contacted if the pressure soon drops again, or the pressure gauge enters the red section when the heating is on.

The water way in the internal filling loop is extremely small and although it sounds like a lot of water is passing it is only a small amount

Hi, bit of a long shot as this is an old thread, however I am trying all avenues... recently moved into a property with an old TurboMax boiler, with two filling loop valves - identical to the kind shown above and the Vaillant self help page;

http://www.vaillantservice.co.uk/Vaillant_Boiler_Self_Help.html

Unfortunately, the screwdriver slot on the right hand valve is damaged, and therefore will not accept a screw driver head to adjust. I have tried a variety of rad bleed keys, and purchased a TurboMax Plus filling loop valve handle, but this doesn't work as the space on the key doesn't fit the valves to turn because the valves are circular head, and the keys are square. Pic of valve attached.

Is there a known key that can be used to adjust these loop valves does anybody know, or has anyone used anything alternative that works?!

All the best and thanks.

If I was you... and this is me being sensible (having learned over time) then I would employ someone to fit an external filling loop to this boiler. Once you do that the refill times go from many minutes (30 to 45) to a few seconds. At the same time you could get a magnetic filter fitted to the system, if it doesn't have one, to improve things further. Then you never need to worry about these slots ever again.

But, if the slot in the screw head is so threaded that a flat-bladed screwdriver won't work, then it's unlikely the special key it comes with will work either (as you say).