I've settled on an Intergas boiler.

[Stan]

I have posted a few times, mainly regarding my indecision to go for either an Ideal or an Intergas open vent boiler.

Having taken note of comments here and having, today, visited [with my installer] a local Plumbase shop to see the area Representative/Contracts Manager displaying an Xclusive combi boiler I (we) have pretty much decided to go for a 30kw Xclusive Combi. The bigger (36kw) is a bit too tall to fit the space).

Initially, and by way of a sort of compromise, I will probably have it fitted as an OPEN VENT boiler which fulfills my desire for retaining an unpressurised system and in keeping the F & E in place - and will upgrade to a full combi heating system at a later stage - i.e. if the hot water cylinder starts to leak or something else forces my hand.

The feeds to the boiler are currently from above and I'm told there isn't a stand off frame currently available and in order to run the pipes behind the boiler the rep. suggested standing the boiler off the wall using two lengths of 2" x 2" and a board made from something like 18mm ply. Both the rep. and the guy in technical confirm there's no need for a heat resistant backboard.

I have a 22mm gas supply to the boiler. I'll fit a Magnaclean Pro 2 and will have the system flushed. I'll change the present manual bypass (in the cylinder cupboard) for an automatic one. I have already run a 3 plus earth cable from the cylinder to the boiler.

What, I wonder, have I missed?

Thanks to all who advised previously and led me towards the Intergas option.

 

[Aire]

Don't believe it will work as an open vent. Instructions say below 0.5bar, you will get a low pressure warning and the heating will function at a reduced capacity. 0.2bar and below and the heating won't function.

Also, why keep the cylinder when fitting a combi?

 

[Stan]

Ah - there you have me. I am only going by what the Southern Area Contracts Manager tells us when he demonstrated the boiler today.. And the fact that all their advertising blurb says you can run them as open vent. Obviously I can't speak from any position of authority myself. I will need to be satisfied that either he's right or you're right.

The idea of keeping the cylinder relates to the fact that originally I was determined to replace the old open vent Ideal boiler on a 'one for one' basis - keeping it simple by retaining the F and E and seperate Grundfos pump and the three way valve etc.

Then it seemed that I could keep my options open by just fitting the Xclusive combi and keeping the open vent system and being able to convert to full combi operation at a later stage if need be. That way I get my wish to keep an open vent system in the short term but can conform to everyone elses recommedation to have a combi - at some later date.

Many thanks for the quick and very pertinent reply!

 

[Aire]

You can have it as an open vent so long as you can maintain 0.5bar pressure. Not knowing the distance between the base of your header tank and the top of your boiler, I can't say whether the required pressure can met.

 

[Stan]

Give me five minutes and I'll measure it.

Ta.

 

[Stan]

Base of the F & E to top of the boiler = 12 feet or 3.6 metres.

 

[Aire]

That will give you approx 0.36 bar of pressure. If you can raise the tank a further 1.4 metres that should give you enough pressure for the boiler to function correctly.

 

[Stan]

Mmmm. Do I want to go to that trouble?

Food for thought.

Grateful for the advice though.

I haven't committed to anything as we speak.

 

[Aire]

That's completely up to you. Is there a reason your wanting to keep your system as an open vent? Is there a real risk of pipes bursting etc or is it just a fear you have?

 

[Stan]

The latter. It's a 23 year old 10mm microbore system with the ground floor fed from drops in the first floor void and the manifold is under 8 x 4 sheets of tongue and groove chip which is under tidy carpet etc, I dread the thought of a leak caused by me pressurising the system when I could have left it as it was. However - everyone tells me not to worry.