Low pressure in Vaillant ecotec plus (NOT combi)

Omlettio · 23 Mar 2007

Hello,

I am new to this forum, and have just spent the last couple hours browsing posts looking for an answer to a problem I have. Unfortunately, I had no luck so was hoping someone could help me!

The system - recently installed Vaillant ectotec plus condenser boiler , which is connected to a hot water cylinder (indirect - heated by coils in it), and central heating (3 way valve). There is a large cold storage container in the loft, and a smaller one which I believe you call a "vent/overflow". Based on this, I understand it to be a "open vented indirect system".

The problem - error code F.22 comes up, and the boiler will not heat water. the manual says this is low pressure in the system, and that it needs "filling up" to over 1.0 bar. The current pressure reads 0.4.

Questions -

1) The instructions are not clear on how to fill the system up to increase the pressure. Could someone explain how to do this? It seems quite easy on a combi sealed system... but not with one like mine.

2) Even if the pressure was increased, wouldn't this just mean that water would overflow in to the vent/overflow (small container in the loft), and thus the pressure would decrease again, since it is an UNSEALED system?

Apologies for the long post. I hope someone can help me solve this problem!

ps. have checked for leaks in the system - there are none. The system was at about 0.5 bar and worked for 6 months, and recently it dropped to 0.4 bar and displays the above problem quite regularly leaving us without hot water!

Bamber gaspipe · 23 Mar 2007

An open vented system boiler with a pressure gauge, interesting,where is this pressure gauge? you sure its not an unvented system?

Omlettio · 23 Mar 2007

hello

thanks for your reply.

the pressure guage is on the front of the boiler, in digital, and a pointer. the pointer should be in the grey area, but it is below that.

apologies if it is not vented/unvented - these are just terms i picked up from the site.

Bamber gaspipe · 23 Mar 2007

Then you need to re-pressurise the boiler. Can you see just beneath the boiler a silver braid type loop? You can`t have a hot water cylinder or any tanks in loft unless I`m completely insane. (wouldn`t surprise me) unless you have an unvented cylinder. ( no tanks in loft). Help me out here.

Omlettio · 23 Mar 2007

No, there isn't one of these.

Are you referring to a "filling loop" ? I thought these were for combi boilers?

regards

ps. the hot water cylinder is on ground floor by boiler. in loft there is a large cold storage tank, and at the highest point a feed/expansion tank.

Bamber gaspipe · 23 Mar 2007

An open vented indirect system,you can`t pressurise the boiler it`s not a sealed system it can`t be pressurised, are you winding me up?

simond · 23 Mar 2007

What model ecoTEC is it? If you have a 4 series then it is an open vent boiler.

But these have only recently come out (and we have found to be very poor build quality, looks like a Gloworm inside - I thought Gloworms were meant to be getting more like Vaillant, not the other way round).

If it is a 6 series ecotec then it must be connected to a filling loop. If someone has connected it to an f and e tank that is rather worrying, for it to show 0.5 the boiler must be around 15 feet below the tank - is it?

More likely the filling loop has been put in remote to the boiler, perhaps near the cylinder or tank.

And lastly, why have you not followed up with your installer?

Bamber gaspipe · 23 Mar 2007

Open vented system boiler with filling loop? I must be falling behind,please explain if you wouldn`t mind Simon?

Omlettio · 23 Mar 2007

Thanks for your reply simond.

It is an ecotec PLUS 624.

I am now becoming very confused.

I will be calling the installer - he is just a pain to get hold off, was hoping it was something easy i could fix myself.

ps. simond - are u surprised about the f & e tank because the ecotec already has a 10L one built in?

gas4you · 23 Mar 2007

You should have a filling loop somewhere as bamber says. It may be under the boiler, or even in the airing cupboard. If so open this until pressure guage needle reads about 9-10 O'clock position. You can check accurate reading by pressing 'minus' button under display. Should read about 1-1.2 bar cold.

600 series do not have built in filling loop.

Although not relevant to your question, if ever you drain system or boiler, remember NOT to just fill up and turn on!

Ecotec plus range needs the boiler/pcb to purge the system/heat exchanger of air by setting 'P 0' on turn on. Failure to do this could end up with an F76 fault and the only way out of this is a new primary heat exchanger

By the way te f&e tank will be (should be) disconnected from the sstem. Your installer probably just couldn't be bothered to remove it

Omlettio · 23 Mar 2007

thanks Gas4You - very helpful.

would someone mind briefly explaining why this kind of system doesn't need an F&E?

everywhere i've read on the internet which has a diagram for a conventional boiler system has a F&E?

regards

2face · 23 Mar 2007

basically u have a combi with added controls to run a cylinder .. possibly to the bath only ??
the installer has added a f&e tank to the system .. i would alter this to a pressure vessel so the f&e is done away with ..

http://cgi.ebay.co.uk/pressure-vess...tcZphotoQQssPageNameZWDVWQQrdZ1QQcmdZViewItem

i have seen this done before but it is a strange way to pipe a system .. i would of either used a system boiler .. or combi traditionally installed ..
the cheapest fix for you is a pressure vessel so you can pressure the system .. the boiler will not fire @ 0.4 bar .. due to safety issues etc.

another way is to raise the f&e to increase head .. but to be honest soundds like a problem waiting to happen .. do it properly ..

john

Omlettio · 23 Mar 2007

I think everyone is confused about what boiler I have!

I do NOT have a combi boiler - it is a system boiler!!!

hmm....

Timmyturtle · 23 Mar 2007

Sounds to me that it has been fitted to an open system and not converted to an unvented/sealed system.
Its not even difficult to change and makes life easier in the long run
It should be unvented/sealed

Timmyturtle · 23 Mar 2007

The 624 system has a pressure vessel in the main cover so has to be sealed.
I have a 618i system

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Low pressure in Vaillant ecotec plus (NOT combi)

Bamber gaspipe

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Bamber gaspipe

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