Open Vented Combination Boiler

[Anton]

Hi,

Does anyone know of a Manufacturer that produces an open vented combi as opposed to a sealed system
combi? (it's for a job where all the system pipework is buried.
Thanks in advance.

 

[tipintim]

I thought all combis can be tank fed providing you got the head.?

 

[Halesowen1]

Trace down GasMarc on here, I am sure he reckons the Intergas can be used as a combi, sealed system boiler or an unvented.
Dont take me word for it, have a look at intergas website and contact GasMarc.

 

[tipintim]

Am I wronge in thinking that?

 

[Halesowen1]

All the combis I have worked on need a certain amount of pressure to work, 0.5 - 0.75 bar, I dont see how you could acheive this as it would be an open system so pressure would be low, but I am sure Intergas get round this somehow.

 

[jtsplumbing]

Think the problem is that all the connections come from below the boiler ! so can-not vent heat exchanger, how old is excisting system? Do they want a combi ? if so just make sure that you tell them about the risk of the old pipe leaking, write it on invoice and get them to sign it,

 

[tipintim]

Well I grew up fitting this type of system. Maybe Im wronge, sure someone will pull me on this.
Im positive that it can and still is practiced. Shoot me if Im wronge

 

[Anton]

Thanks for all the input.

The boiler that's in now is a Worcester open vented combi which is knackered.
If it has to be a sealed system/pressurised then fair enough, that's what will have to be done.
The old open vented Worcesters had the 22mm open vent pipe left hand side and out through the
casing. Combined cold feed/open vent 22mm in FE tank.
Will hang on for a while and see if anyone else has any ideas (will have a look at Intergas website)
Thanks again

 

[Mbear]

I reckon youd struggle to get one now. Most if not all new combis are piped from the bottom therefore you would have air trapped in the main h/e.

Also most new combis have low water pressure switches built in, most Set at 0.5bar-ish. It'd be difficult to achieve on an open sys plus bridging out a safety switch is ID and riddor reportable

 

[quality]

You can pipe an intergas on open vent for the heating

 

[stevetheplumber]

Vaillant used to allow open vents on there boilers you removed safetyvalve and run a cold feed vent from there doubt if this applies to any of the newer models

 

[mottthehunter]

Thanks for posting Anton,I have registered now so will be able to see all the replys

 

[Anton]

Had a look at the Intergas Combi. No mention of the possibility of using F & E tank in the installation instructions.
Did find this in the commisioning part of the installation instructions which I thought strange:
"With the boiler operating in the maximum rate condition check that the
operational (working) gas pressure at the the flue gas sampling point (X)
complies with the requirements of § 10.7.2.
Ensure that this inlet pressure can be obtained with all other gas appliances"

 

[Billy Bob Bob]

its simple really,you cant use any combi with a low water pressure switch most of these need 1 bar to activate,you can however use any combi with a pump pressure switch,baxi 105 he springs to mind but you cant fit these anymore,not legally anyway,find a boiler with a pump pressure switch and no LWP and speak to the manufacturer regarding suitability

 

[broggo]

Trace down GasMarc on here, I am sure he reckons the Intergas can be used as a combi, sealed system boiler or an unvented.
Dont take me word for it, have a look at intergas website and contact GasMarc.

Ive heard this, Apparently one boiler does the lot.

 

[tamz]

Worcesters don't have a low water pressure switch.

 

[Anton]

Thanks for all the advice. Will check with Worcester tomorrow. The Intergas boilers look good. Don't know what the parts availability is like though.