Do I need an external expansion vessel for my Vaillant system?

[retired man]

Hello all

I am new to this forum and I do not want to undertake any work myself. I just want my heating system to work more effectively. Apologies for such along first post but I see from reading other posts that giving as much detail as possible seems to lead to very constructive advice.

I have an old victorian house with 5 bedrooms. My boiler is a Vaillant Ecotec plus 630 which is in my loft, I have 16 radiators. When I moved into the house I found the heating was poor and so I had the boiler serviced by Vaillant and they told me that I had low gas pressure in the loft and so the boiler was running inefficiently. They also told me that my pump was on the way out that that I should also consider having my system power flushed. I used a local gas safe company to do the following last January:

• run a new gas pipe top boiler
• replace pump
• power flush the system

My system now works much more effectively but I have two problems that I am keen to resolve:

• my boiler pressure runs into the red when the system is turned up high. I called out an enginer when this first happened and he advised that I let water out of the system which works but feels like a temporary solution.
• the radiators in my lounge never get above luke wam and the room is unusable on very cold days. I am told that the rads in my lounge are on the end of the run from the boiler and so they are last to warm up and first to do off. My other radiatiors all work fine.

When Vaillant serviced my system recently they told me that I should consider having an external expnasion vessel for my heating since that will stop the boiler pressure going into the red. Having spent £2000 so far I would be grateful to know if the experts on the forum think fitting an expansion vessel will overcome the problems I have and what a reasonable cost for the work would be.

Many thanks.

 

[Alex Pelton]

An expansion vessel will solve your problem with the pressure going into the red. Wont solve your cold rads at the end of the run Your system sounds like it needs balancing which should solve the cold rad problem. Expansion vessel fitting should take 1 to 2 hrs plus cost of parts balancing is something u can do.

 

[SafeGasInstall]

welcome to forum ,

Now your existing expansion vessel could need recharging . this is 5min job . I personally think you need a new heating engineer as I dont think your system was balanced correctly

 

[diamondgas]

As above ... system sounds like it needs ballancing before you do anything drastic, also as said the expansion vessel most likely needs re-charging to stop the pressure fluctuation! Boiler in a loft .sheeeeeeeesh!!! If you ever have to replace it have it put somewhere sensible

 

[stevetheplumber]

As above ... system sounds like it needs ballancing before you do anything drastic, also as said the expansion vessel most likely needs re-charging to stop the pressure fluctuation! Boiler in a loft .sheeeeeeeesh!!! If you ever have to replace it have it put somewhere sensible

i actually like boilers in the loft what do you have against them?

 

[happyflyer]

i actually like boilers in the loft what do you have against them?

Lofts are for insulation and crap not boilers or pipework or FE tanks or header tanks, who wants to be working in confine dark condition breathing in glass fibre, freezing in winter boiling in summer when the boiler broken down, crawling around on your hands and knees, banging head in beams, to many minuses ..... each to his own

 

[retired man]

Thank you very much for the helpful advice. I will try balancing the system myself and will look for advice on how to do that on the forum.

 

[SafeGasInstall]

easy enough if system installed correctly (pipe sized correctly)

 

[Dotty]

Don't worry about looking, it's all here for you.

View attachment How To Balance Radiators.txt

 

[happyflyer]

Your existing vessel may need topping up however the membrane may be letting water through into the air side, I am a great advocate of not
having a boiler with an internal vessel or pump for the reason you are having now, built in ones are a pig to replace and that's why engineers say fit and external on. Also the internal vessel is limited to expansion size even when it is in perfect condition, an external one can be as big as you want, BTW you only need a very small charge pressure when cold if the boiler is in the roof space, enough to keep the boiler low pressure switch happy. Also if the boiler has an internal pump you are limited to it's head, have an external pump and you can fit any size.

Good luck whatever you do with it.

 

[happyflyer]

Don't worry about looking, it's all here for you.

View attachment 15278

You should patent this or copy write it. :smilielol5r croppie write it

 

[Ermintrude]

welcome to forum ,

Now your existing expansion vessel could need recharging . this is 5min job . I personally think you need a new heating engineer as I dont think your system was balanced correctly

Was going to say the same . Valliant vessels (silver ones ) seem to go flat faster than carling!

 

[happyflyer]

Hi all.

I wonder what the life of the nitrogen charge is on an internal expansion vessel and what the real cause of pressure loss is generally.

We all know if water comes out of the air valve when you take out the core to do the recharge the membrane is leaking, if there is no water then the charge must be a nitrogen leak on the dry side, I have fitted lots of Boss or Brefco vessel over the years and they never appear to give much trouble.

If you re-pressure up a vessel that's got water on the dry side it will only loose the charge again, why manufactures think its clever to fit them in the boiler I will never know, space yes.

What's your experience on the issue

 

[diamondgas]

i actually like boilers in the loft what do you have against them?

As happyflyer says, lots of negatives, Lighting, access, having to hump tools through loft hatches and usualy a dusty place. My main concern is that they're at the 'top' of the system where lowest system pressure is registered. Any small weeps on an existing system have the boiler's constantly tripping off on low pressure! And the re-set/top-up is in the loft with the boiler so the custard soon finds out how stupid an idea it was to put it there! You loose out on recomendations by that customer... IMHO

I remember a saying from many moons ago ' do a good job and that customer will pass your name on to maybe one or two people. Do a bad job and they'll tell EVERYONE they know!' Most quality leads come from your existing customers in my experience

 

[happyflyer]

As happyflyer says, lots of negatives, Lighting, access, having to hump tools through loft hatches and usualy a dusty place. My main concern is that they're at the 'top' of the system where lowest system pressure is registered. Any small weeps on an existing system have the boiler's constantly tripping off on low pressure! And the re-set/top-up is in the loft with the boiler so the custard soon finds out how stupid an idea it was to put it there! You loose out on recomendations by that customer... IMHO

I remember a saying from many moons ago ' do a good job and that customer will pass your name on to maybe one or two people. Do a bad job and they'll tell EVERYONE they know!' Most quality leads come from your existing customers in my experience

Spot on with everything you say from a "Diamond Geezer"

 

[Centralheatking]

A new expansion vessel and filling kit for this set up is only £50 + vat to buy even if the system needs one.(Bes gas controls)

I agree with above loft installations are pooh and should be boarded out and lit etc
and @ £40 ish for a new ext pressure v. is dead easy - avoid factory made replacements
for any combi make they probablycost the earth centralheatking

 

[Ermintrude]

Think list on valliant is £275

 

[Centralheatking]

You and I live in the real world - well quoted Ermin v

Think list on valliant is £275

 

[happyflyer]

Think list on valliant is £275

Are you sure Ermi, there in the common market like us, that's a lot different than £50,

£35 for this 18L one, about time you lads started filling your profile and tells us where you live then
we can perhaps understand why the difference in prices.

 

[Centralheatking]

Come on Mr Croppie - if a boiler is located in a loft space - what are the
requirements to keep us all safe. I understand from friends at BG in low places that the
loft space MUST be borded (cant spell) and be a 'safe area' before any engineer can go up
- please keep us safe Jon

CHK

A new expansion vessel and filling kit for this set up is only £50 + vat to buy even if the system needs one.(Bes gas controls)

I agree with above loft installations are pooh and should be boarded out and lit etc
and @ £40 ish for a new ext pressure v. is dead easy - avoid factory made replacements
for any combi make they probablycost the earth centralheatking

 

[Centralheatking]

WOW chk

Think list on valliant is £275

 

[Ermintrude]

Are you sure Ermi, there in the common market like us, that's a lot different than £50,

£35 for this 18L one, about time you lads started filling your profile and tells us where you live then
we can perhaps understand why the difference in prices.

View attachment 15310

Call your parts desk tomorrow and ask for original valliant silver ex vessel . Well over £250! List price .

 

[happyflyer]

Call your parts desk tomorrow and ask for original valliant silver ex vessel . Well over £250! List price .

Ermi,

Why would he want to do that when he can get a vessel that will last longer for less than £50.00 twas you yourself who said they go flat like larger, and to get to the new internal vessel fitted would have to remove the boiler case, whoops, no can do. Leave the old tosh where it is and fit an external one. If you had a Ford van would you always insist on fitting FORD OEM parts on it.

 

[Ermintrude]

Sorry. I would never advocate installing a valliant one they are pure pish. I was saying that they are ludicrously expensive ?? My tread is a little pish, distracted with electronics problem on network. Testing but takes ages. Sick!!

 

[diamondgas]

Come on Mr Croppie - if a boiler is located in a loft space - what are the
requirements to keep us all safe. I understand from friends at BG in low places that the
loft space MUST be borded (cant spell) and be a 'safe area' before any engineer can go up
- please keep us safe Jon

CHK

CHK ... If my memory serves me right there should be good lighting and access plus floored out. The loft ladder also requires a hand rail.