Underfloor heating - how to isolate?

[Nivamc]

Mumsnetters, can you help? I have a leak in our underfloor heating and I want to isolate the system from our main boiler as the pressure keeps on dropping. I’m not sure what levers to turn - does anyone know?

By the looks of it red and blue circle will isolate the pump and the flow and return. The green and yellow circles look to be for draining the system off. Not an expert but that’s how it looks from that photo.

It looks like red circle is your flow and blue is your return. Once those have been isolated operating your other two with a bucket underneath will allow you to drain down the UFH pipes provided they’re under pressure or the pipes are above the tap.

Thank you! Only a trickle of filthy water drained out but hopefully that will do the trick until I can get a plumber to look at it.