External expansion vessel to vaillant ecotec boiler

[Dannyj1984]

We have a 10 year old vaillant boiler and at its annual service this week we were told that the expansion vessel had failed. A new one costs £300 Inc fitting. As the boiler is 10 year old I had a look at an external one we can fit ourselves.

It looks like I can get one with all the necessary bits for £60 (quoted 150 by the gas engineer for an external one)

Expansion vessel 18litre £24
Piece of 15ml pipe £4
Couple of elbows and a tee £10
Bracket £10
Connectir for the EV to the pipe £4
Bottle of inhibitor £10

I have watched videos online and looks a simple job.,

Drain the system, cut into the return 22ml pipe, but if pipe to the location of the expansion vessel, connect the EV to the 15ml pipe. Add the inhibitor, the EV is pre charged to 1 bar. Top up the system and bleed radiators and the new EV. Make sure no leaks......

Have I missed anything obvious?

Many thanks

 

[ianmcd]

What if the new EV is not charged to 1.0 Bar ?

 

[Dannyj1984]

Hi, I have checked and the new EV I am looking at is pre charged to 1 bar.

Thanks

 

[undertrained]

Hi, I have checked and the new EV I am looking at is pre charged to 1 bar.

Thanks

I think what he means is, although it’s stating 1.0 bar, but could arrive faulty? Little bit of air gets out, hardly any expansion, back to where you started.

 

[ianmcd]

I see many boilers brand new with depleted expansion vessels, I have seen brand new expansion vessels completely discharged £150 to supply and fit an external expansion vessel is a good price, if you actually need one

 

[Dannyj1984]

I think what he means is, although it’s stating 1.0 bar, but could arrive faulty? Little bit of air gets out, hardly any expansion, back to where you started.

Yes I suppose that could happen, but can I not just check when it arrives? to check what pressure it is showing?

 

[Dannyj1984]

I see many boilers brand new with depleted expansion vessels, I have seen brand new expansion vessels completely discharged £150 to supply and fit an external expansion vessel is a good price, if you actually need one

It looks as though the gas engineer is charging £100 labour for an hours work? probably more as they will get the parts cheaper than I can.

 

[ianmcd]

It is just a myth that we get parts cheaper than you , if you do it yourself and it goes wrong you will wish you had used a professional, have you considered if the existing is actually faulty , does it need isolated from the system ? , does the prv need replaced ? you said about bleeding radiators ? why would you have to ? totally up to you to do this by yourself , just saying not as easy as you might think , I know many so called heating engineers that havent a clue how to test an expansion vessel

 

[undertrained]

Yes I suppose that could happen, but can I not just check when it arrives? to check what pressure it is showing?

You could, but I doubt it will show you. I agree with @ianmcd , you don’t know for certain that it has failed - it might just need recharging. I work on Vaillant Ecotec Pro’s on a daily basis, dating back to the R1 model (2006) and at first I didn’t know how to properly check them or recharge them. I did however know if it needed replacing.

A lot of engineers will obtain parts through a merchant as they have accounts with them, so you might be able to get the part cheaper.

 

[Dannyj1984]

Well I presume a heating engineer would buy in bulk and the website I am looking at the EV from states it is £5 cheaper if you buy 5 or more.... you can bulk buy inhibitor fluid which halves the price etc etc..

Anyway, you make some good points, I am totally in the hands of the guy who serviced it to as whether it is faulty, I have my doubts, I have never had any issues with the pressure, it runs normally and the pressure goes up slightly when the heating is on and reduces back to the beginning of 'safe' zone when it is off. I have never had to top it up, I believe if one of these EV has failed then the pressure should go high when the heating is on and then reduce to 0 when turned off. But the heating engineer said that there was water coming from the valve on the internal EV and looking online this is a common sign of a fault. But as I am not a gas safe engineer and cannot even remove to the boiler cover to check the internal EV to see if the water is actually coming out, I am either left to put an external one on my own, or pay someone to do it. No videos I have seen online mention isolating the internal EV. I have looked online and people seem to say that to test the EV you should drain the system and then check the pressure in it? I doubt he did this unless he threw all the water from the system into the dishwasher in the utility room as it wasnt all put down the sink in the kitchen.

Thanks

 

[Dannyj1984]

You could, but I doubt it will show you. I agree with @ianmcd , you don’t know for certain that it has failed - it might just need recharging. I work on Vaillant Ecotec Pro’s on a daily basis, dating back to the R1 model (2006) and at first I didn’t know how to properly check them or recharge them. I did however know if it needed replacing.

A lot of engineers will obtain parts through a merchant as they have accounts with them, so you might be able to get the part cheaper.

Could you confirm that if there is water coming out of the valve on the EV then that means it has failed and needs replacing? Also could you advise if I need to do anything else to add the external EV as stated in my original post.

Many thanks

 

[undertrained]

Could you confirm that if there is water coming out of the valve on the EV then that means it has failed and needs replacing? Also could you advise if I need to do anything else to add the external EV as stated in my original post.

Many thanks

• Personally I think £300 for that particular job is expensive, but then again I don’t have my own business or where you are based in the country.
• If water is coming from the valve on the EV, then yes it’s rubber membrane has usually perished.
• It looks as though you have covered what you need for replacing external vessel, but I’ve never fitted one, so Ian or someone else will be better suited to answering.
• As for buying in bulk, unless it’s all you work on and have the storage, then heating engineers would not buy in bulk, whereas the company I work for do, because we have approx 6000 houses.

Thanks,

Chris.

 

[Dannyj1984]

• Personally I think £300 for that particular job is expensive, but then again I don’t have my own business or where you are based in the country.
• If water is coming from the valve on the EV, then yes it’s rubber membrane has usually perished.
• It looks as though you have covered what you need for replacing external vessel, but I’ve never fitted one, so Ian or someone else will be better suited to answering.
• As for buying in bulk, unless it’s all you work on and have the storage, then heating engineers would not buy in bulk, whereas the company I work for do, because we have approx 6000 houses.

Thanks,

Chris.

Thanks Chris. I also find it expensive as I have checked with Vaillant and you can buy the EV direct from them for £150inc VAT so that means being Charged £150 for approx an hours work (an hour is what the engineer said it would take) I have no idea how long it would take for an internal one.

Thanks

 

[terryplumb]

If the EV has failed ,you would be experiencing problems with pressure / water loss via the PRV. You advised above that you are not. Although water coming from EV' s valve is indicative of possible failure of the membrane ,its not necessarily so.
If your boiler is working fine , with no pressure issues ,you need not do anything.

 

[ianmcd]

I doubt very much if you need a replacement EV either internal or external, you need someone to service your boiler properly that knows how to recharge an expansion vessel properly, water from the shraeder valve means nothing, the only way you know how an EV is shot is to properly recharge it and see if it will hold a charge