System boiler used in open vented system?

[teylore]

Is it possible to use a system boiler in an open vented system?


The system is in Ukraine.
Currently there is a 25kW gas boiler (cirsa 1950) and unused solid fuel boiler on an open vented wystem.
It is large (4") single pipe system, with large cast rads (about 350 Lts total).
There is over 32' head of water and an expansion vessel at the top of the pipework.
The system was thermosyphoning but now pumped.
The boiler and wood burner air intake is from inside the house and exhaust via flue pipe in a chimney.
The DHWS is done by a stand alone electric water heater (a cylinder may be included in any new scheme).

I want to replace the boilers with something safer and more efficient.

What is to stop me from using a system boiler directly connected to the system? (Manufacturers warranties asside). The system pressure would be maintained at about 1 bar.
Or would the ststem boiler need to be in a seperate circuit and to be coupled by heat exchanger?

For what reasons are system boilers closed circuits? Is this because we live in only two stoey buildings?

If I am missing some basic understanding, or if the question just seems daft, please excuse me.
Any thoughts/ideas would be welcome.

Thank you,

 

[45yearsagasman]

Consult with the local authorities for the local regs comrade.

 

[Agile]

Most modern boilers are designed for sealed systems.

Some the Intergas can work on OV systems.

An Intergas would be particularly suitable as the internal waterways are 22 mm so it is not at all susceptible to dirt.

But a Magnaclean would still be a good idea with all that old cast iron.

Tony

 

[teylore]

Thank you very much Tony. I will look at Intergas.
Is contamination the reason why system boilers are not normally used on open systems?
That and possibly system pressure?

 

[DP]

System boiler is one package appliance with all essential components within the case

If you already have external expansion cistern, fit an open vented boiler along with external pump to aid circulation.