Little help with a (very) old Vaillant!

[Insertusernamehere]

Hi All,

Long time lurker, first time poster!
I have used this site and it has been of a massive help in diagnosing the issues I have been having with my Vaillant Ecomax 824 (note the old one, not the ecotec 824/e)

Please note- I don;t want to fall foul of the HSE rules, but I don't think anything I am proposing is considered gas work as I am not going anywhere near that. Please do correct me if I am wrong.

Normally I wouldn't tinker but Heating Engineer couldn't make it to look at our problem for over a week and I have a pregnant wife in the house....

We recently put the heating back on and the boiler started to lose pressure.
I set a gopro up to capture a timelapse of the pressure valve to see what was going on.

Lo and behold, when the heating kicked in the pressure went over 3bar and dumped out the PRV - confirmed by using a measuring jug which had about 1/2 litre of water in it after it opened.

So, using the excellent knowledge on here I was able to identify that this was most likely due to the EV, below is a detailed list of steps I have taken

Switched off the boiler and left it for a day

I touched the valve on the EV and a little air came out, but only a small amount.

I closed off the valves under the boiler- however I now realise that I didn't totally close off the CH outlet which might explain the issues below.

Drained it via the PRV- I figured it had blown anyway so will be replacing it, better safe than sorry

Added 0.75 psi of air to the EV with the PRV open however I probably didn't leave the pump and guage on long enough to notice if it was dropping off again.

Noted that the EV schrader valve was leaking air so screwed the cap on as tightly as possible in the hope I could just top it up every now and again until the new valve arrives.

Re-opened the CH valves and pressurised to 1bar note at this point I did NOT restart the boiler

15 mins later, pressure was 0 again

Topped it up to 1 bar

15 mins later the pressure was 0 again

Topped it up to 1 bar

15 mins later the pressure was 0 again

At this point I realised that I may not have closed of the CH valve fully, so closed these off fully, drained via the PRV and then re-pressurised the EV

Same as above!

Thought to myself this is ridiculous so I checked the valve on the EV again and lo and behold a little squirt of water came out.

New EV on order!

Now, the only things which worry me are (and I am hoping you can tell me to man up and stop stressing about it)

1- Because I didn't properly close off the CH isolation valve the first time- is this where the additional pressure is going? or when I topped the system back up to 1bar would this have re-filled all the CH system (which is what I assume)? OR is this additional pressure just going into the EV? Or (and I am hoping not) do I now have a leak in the CH system?? I hadn't noticed a loss of pressure like this before, or on the video I took, just the loss when the PRV opened.

2- When I re-pressurised the EV I am guessing the diaphragm was ruptured so do I now have air in my CH system somewhere?

Heating Engineer is booked for next week, but would quite like to change out the EV and get some heating back this weekend!!

 

[Agile]

How are you going to get the old EV out to change it?

Why not wait for the engineer?

When repressurising the EV you should hold the pin down until all the air/water comes out WHILST maintaining about 1.0 bar pressure in the system.

Then repressurise the EV to 0.9 bar WHILST the system pressure is kept at zero.

It is unlikely you need a new EV apart from the leaking air valve.

Tony

 

[Insertusernamehere]

Hi Tony,

Thank you for the very speedy response!

That is interesting, from googling I had assumed that the fact water was coming out of the schrader valve meant the diaphraghm had probably given up.
I believe I followed the process you have outlined when recharging the EV.

Maybe I will just wait a week for the engineer and dig out some electric heaters... or find someone who can come out sooner!

 

[Agile]

It is very common to get a little water out of the air valve.

But if you let the water out then they will usually work fine.

If you think for a moment there is no pressure across the diaphragm in operation so no reason the water would migrate to the other side.

I suggest you repeat recharging EXACTLY as I described and you may find it works.

Tony

 

[Insertusernamehere]

Thank you Tony, I will try the EXACT process tonight and see how it goes.

Thank you for the assistance

 

[kidgreen61]

and I have a pregnant wife in the house

Yes, but is she your wife?

 

[Insertusernamehere]

and I have a pregnant wife in the house

Yes, but is she your wife?

hahaha!

yes, and very happy with Tony as we seem to have heating again.

Boiler seems to be operating nicely between 1 and 2 bar, will check in the morning though.

Will get the HE to check it all over and change the schrader valve out on the EV

 

[Insertusernamehere]

So this morning the boiler was back down to 'min' but not totally empty

So I am assuming (and please correct me if I am wrong) that either:

1- the air is being forced out of the leaky EV valve and therefore the water side is expanding and thus the pressure drop

2- all of the air was forced out and the EV didn't stop the boiler over pressuring and it went out the prv again?

3- The PRV is leaking enough to get that drop- but that seems like a lot to drop just drop slow dripping

 

[algas]

you may now need to replace the prv as it probably will have crap on the seating thats why its dripping

 

[Insertusernamehere]

Yep I figured that one, but I will let the HE do that correctly.

Just wasn't sure if that was too much loss to be a dripping PRV, but I guess the measuring jug test tonight will tell me!

 

[Agile]

There is no point asking us! We are not there and don't know what is happening.

You can see if water is coming from the PRV vent by putting a bottle over it.

You can see the pressure increase from cold to hot when you put on the heating. It should increase from about 1.5 bar by about 0.3 bar.

If the PRV is leaking then you can "click" it about three times by turning against the spring until it clicks. That will often stop it from dripping.

Tony

 

[Insertusernamehere]

I appreciate that, I was merely looking for some advice on the possible scenarios and a clarification on my assumptions, I am not expecting anyone to diagnose the exact fault based on words on a screen.

Thank you for the advice so far and I am glad to have some heating, I will pick this up with the HE next week.