New expansion vessel needed?

[scotster]

Hi all.

My Vaillant Ecoplus 360 seems to be having issues. When cold the pressure is bang on mid range but seems to run high when the heating is on. See pics. When I prod the valve on the expansion vessel water squirts out so I think its jiggered and needs replacing.

Just checking I havent misudnerstood all the youtube videos Ive watched before I call someone out to fit a new one.

Thanks for any help
Scott.

 

[terryplumb]

Worth trying to recharge the expansion vessel before writing it off and replacing it.

 

[scotster]

I’ve read it might be condensate that’s collected so I’ll make sure everything is drained out and do as you suggested.

 

[ianmcd]

Make sure you leave a drain point open while re-pressurising or no point in doing anything

 

[scotster]

Thanks Ian. I did it last night. I drained down everything (including the water in the PV valvle) then pumped up the PV to 1 bar whilst the drain on the boiler was still open. The PV seemed to hold pressure for the 5 mins I left it so it may be OK. I refilled the boiler and ran the P0 programme to flush the air out and tried again. The pressure gauge was only marginally less high than before when running with all the CH on this morning. Could it be the PV is not big enough for the system? We have a relatively large 5 bed detached with new column rads throughout. I wish Id paid more attention to the gauge when CH on before as it may have been like this a while. Ill check for water in the PV again and if thats OK Ill probably get an engineer in to give the whole thing a look over. Im not sure of that amount of pressure raise is normal?

 

[terryplumb]

Looks like you are setting the initial pressure in your system too high. Try dropping the cold sysyem pressure . It's normal for system pressure to increase when CHeating is on. There may not be an issue with the EV at all.

 

[Iddy]

How big is you heating system, how many radiators?
What's the 'head' of the system above the boiler i.e are you in a bungalow, or boiler in attic, or boiler on ground floor of a 3 storey?
Initial charge of 1 bar may be a little high.
If you precharge the EV to say, 0.7 bar, then fill system to 1.2 bar, does the air pressure in the EV then show 1.2 bar (to confirm the connection to the EV isn't blocked)

 

[scotster]

Thanks Terry and Iddy. Single story house with bolier on ground floor, 12 rads most of which are column style and UFH in kitchen area about 5mx5m. Im pretty sure EV is not blocked as when I pumped it with drain open you could clearly see it making water come out of the drain a little more. BUT I will try your test. I think Ill also switch to running the cold at a lower pressure to start with as its now at 1.5 when cold.

 

[terryplumb]

Set the cold system pressure to 1 bar.
What pressure did you charge the EV to ?

 

[Johntheo5]

Thanks Terry and Iddy. Single story house with bolier on ground floor, 12 rads most of which are column style and UFH in kitchen area about 5mx5m. Im pretty sure EV is not blocked as when I pumped it with drain open you could clearly see it making water come out of the drain a little more. BUT I will try your test. I think Ill also switch to running the cold at a lower pressure to start with as its now at 1.5 when cold.

What is the EV volume and we will then be able to calculate exactly what system volume this will service at different pre anfd filling pressures.
Also the boiler flow temperature.

 

[scotster]

Set the cold system pressure to 1 bar.
What pressure did you charge the EV to ?

1bar - Ill drop it to that. Currently set to 1.5 cold and rises to 2.3 with all the heating on. It was running higher than that before I got the water out the air side of the EV so that has helped. Not sure if that amount of rise is acceptable? EV was pumped to 1 bar when everything was drained in the boiler.

 

[scotster]

What is the EV volume and we will then be able to calculate exactly what system volume this will service at different pre anfd filling pressures.
Also the boiler flow temperature.

Hi John. The EV is this one at 10 Litre. https://www.unventedcomponentseurope.com/vaillant-ecotec-expansion-vessel-181051-all-models.html/ Bolier flow temp is 70C. Thanks.

 

[Johntheo5]

You can do your own calculations below.

A 10L EV with pre&filling pressures of 1.0/1.5bar will give a final pressure of 2.5bar, system vol 125L. Will lift the PRV (3.0bar) with a system contents of 160L
A 10L EV with pre&filling pressures of 1.5/1.5bar will give a final pressure of 2.5bar, system vol 155L. Will lift the PRV (3.0bar) with a system contents of 200L.
You can figure out your own system contents.

 

[Johntheo5]

1bar - Ill drop it to that. Currently set to 1.5 cold and rises to 2.3 with all the heating on. It was running higher than that before I got the water out the air side of the EV so that has helped. Not sure if that amount of rise is acceptable? EV was pumped to 1 bar when everything was drained in the boiler.

That rise is quite acceptable.
You said you got water coming from the schrader valve, it would take around 3/3.5L of water to enter the air space to lift the PRV and except you are pumping up the air end every few weeks, condensation would take years, if ever, to build up to that level, I,d be a bit suspicious that the diaphragm is on the way out, also spray some soapy water around and on the schrader valve to check for leakage. Just keep a eye on it, could last for years, I have the original EV on a 14 year old Solar System.