Danfoss HIU top up pressure

[cyteh84]

Hi,

I need to install TRV on 3 rads in my flat. I'm looking at my Danfoss HIU (picture attached). I cannot workout how can I top up the pressure if I were to drain the system to install the TRV. I might need a filing loop for this.

Anyone familiar with this HIU?

Another question, would it be possible to not drain the system to install the TRV for this HIU?

Thanks,

 

[Deleted member 120897]

It looks like it’s the 2 valves with the filling loop sat on top of them. You probably don’t need to drain the system, just the leg, but I’d certainly turn off the flow and return from the incoming communal heating.

 

[cyteh84]

Hi, I have drawn some line in the picture.

Should I connect the filing loop on the blue line? or the yellow or green? The valve green and yellow connect is where the cold water main come in.

Once I connected the filling loop, I have to turn on the valve (the valve look like one underneath the sink that you need to use a screwdriver to turn). then check the pressure gauge until it's between 1 and 1.5 bar. Am I right?

Thanks,

 

[Deleted member 120897]

Yes one to the cold main (yellow line to blue) it appears that there’s two valves on the flow and return, but usually just the return. Yes pressurise to 1.5 bar is fine.