'Expansion Pressure relief valve solar underfloor heating' type Question

[Phil]

Can I dip into the vast knowledge base just one more time please


  I have a Navitron supplied pressure vesel and valve for use with my solar tube system,  can I also use this pressure vesel with my underfloor heating pipes or do I have to keep the two systems seperate.

 Both systems use seperate coils in my vented Themal store

If I cant, how can I provide my underfloor heating with feed and expansion ( a seperate pressure vessel ?  maybe I have answerd my own question? )
 
Thanks

[ajstoneservices]

Hi Phil,
You need to keep them seperate as you have two circuits.

And yes another vessel.

[Phil]

Is there anyway of doing without an Expansion vessel ?

[ajstoneservices]

Hi Phil,

The sealed system is the best approach for your solar and underfloor heating, you could use a drain back system for the solar and an open vent with an expansion tank for the underfloor.

If it were me, two sealed systems, and they would work out cheaper.

tony

[Phil]

Hello Tony,
   Thanks for taking the time, can you explain how an open vent with expansion tank works ?

 I cant see how you stop the water pouring into the expansion tank when the underfloor pump switches on ?