Duncan62

I think this may be my issue, I knew not to offer tighten, so maybe didn't do it enough. I only have normal spanners so don't think I could have overtightened as wasn't forcing anything... I'll open one up and look at the pipe, hopefully it doesn't look like a fat finger on a ring! Been advised to add some paste to the olives before tightening to help with the leaks.

So, filled with water. Lots of leaks.... Which was unexpected. Going round tightening everything again.

I'll check the heat pump thank you. Airless trap because I had already bought it but for airtightness test it's useless for the pressurisation test as it blows straight open, so added a u bend too.

Thank you all, uninsulated until I get it up and running in case of any leaks, but system installed and closed loop. Next challenge is flushing the UFH loops (only 3x100m) and filling the system from the now connected fill hose under the expansion vessel. Also need to add the biocide and anti-corrosion. Wish me luck.

Thank you so much. I've got outdoor lagging and will do as you do!

Thinking about it, should the Freezer valves be sited at the lowest point before the heat pump, or will anywhere outside do it?

Magic thanks.. ordered some freeze valves. Q4: Is it standard practice to put BOTH inhibitors and biocides in the UFH loop?

Do I need one on flow and return? Or just one, before the heat pump outside?

These anti freeze valves seems pricey: https://www.macdonaldplumbingsupplies.com/heat-pumps-accessories-c682/anti-freeze-valves-c685/inta-28mm-anti-freeze-valve-zero28-p16592 Over £100 per...

Oh ok. Where in the loop do I need that, any recommendations for make?

I have the filter on the outflow, an Intaklean unit. Nothing anywhere else.

Q3: How much"flushing" of the system is required? I've put it together and been very careful along the way. Happy to flush, presume that's what the fill flush valve is for, so I can have the dirty water exit before the HP. Just want to know how critical this step is.

Thanks guys. I shall check the manufacturers booklet again. Perhaps the actual flow temp anti freeze valve is best... I certainly don't want to compromise on CoP!

There is just 1 currently, as nick pointed out, on the UFH manifold. The pipes running upstairs are for a FCU and there is no bleed on them. Shall I add one up there?

Hello all, thanks to the fantastic BH I've had a go at my UFH / DHW install. Be nice (please!) but tell me if it's wrong! Q1: how do I go about filling the system? Do I use the full and flush valve, hose pipe? Or pipe in a hep2o from mains? Q2: I have a huge plastic container of glycol for anti freeze. How do I get that in the pipes? How do I get the correct ratio? Observations: DHW Will loop to UVC, but currently loops back to exit so I can get the system running as I need to commission the slab with heat cycle.