New boiler - open vent or sealed

[Maboza-Ritchy]

Hi
I'm intending to replace old Baxi WM38/3RS with Vaillant EcoTec plus boiler. The Baxi has an F&E tank, my question is; should I keep this and use an open vent boiler or replace with a sealed boiler & do away with F&E?
What are the pros & cons with either system?
Your advice will be appreciated.

Steve

 

[Paul Barker]

Vaillant specify fairly standard by modern methods open vent set up. flow from boiler to open vent (22mm) within 150mm of that cold feed (min 15mm but I suggest 22mm, vaillant show the classic puled bend with cold feed sweeping under flow pipe to T in from beneath) followed by pump flowing away from boiler to auto bypass then mid pos valve or branch before S plan valves. (Bottom of F/E tank 1m above top of boiler)

Whether your existing system is like that or has gravity hot water with open vent on top pipe of cylinder coil and cold feed on bottom with pump on return from heating. Or some other system of which there are many. you will have to find out and apply changes.

For a sealed system fairly standard sealed system kit PRV on flow right beside boiler they show EV on flow but I would place it on return for an easier life.

I often fit a very succesful semi sealed installation for old people who can't understand filling loops. I use an FE tank 1m min above boiler but use 22mm feed no vent put a PRV on flow from boiler. You have a sort of self refilling low pressure sealed system. I find it the best option for the elderly which forms most of my customers..

 

[namsag]

??? paul what is sealed about that or even semi sealed.
All it is ,is a combined feed open vent as was asked for on a number of low water content boilers and because the water is always expanding and contracting up and down the pipe it should never block but boiler should have appropriate overheat protection

To op sealed system will always work better than an open vented system so if your pipework and rads are ok then go for a sealed system .
If you have pipes buried in concrete then you may have to be a bit wary.

 

[simond]

If you can fit the 6 series sealed system Vaillant boiler this is a better product than the UK only and Glowworm-inspired 4 series open vent.

 

[Maboza-Ritchy]

Hi all, and thanks for the replies. Just to clarify, I'm in a one bed ground floor flat ( I can get underneath floor if need be) Baxi is in the bedroom cupboard, HW cylinder in air cupboard with a shelf about 7 foot above floor level where F&E tank is situated. CH is micro-bore with 6 rads. I'd like to do away with F&E as this would give me a wee bit more storage space.
So would a sealed boiler be physically bigger, involve more work, cost more that an vented boiler?

PS given the info above is there another boiler you would recommend to replace the Baxi?

Cheers.

 

[namsag]

BY Description i would go for a sealed system because even if existing system had any fault it would not cause any damage if it leaked.
System boilers are a bit more expensive as they come with a few extra bits in them and the pump as for makes everyone will have there favourites

One bedroom flat would suggest max 2 people in house. Have you considered going for a combi as this would free you up even more space and be cheaper to run