Can't you fettle a length of garden hose to feed the cold temporarily, just to try it.
Hot temperature at flushing nozzle = 65C (measured using a calibrated electronic meter at the hot flushing outlet)
Taken from the Trevi Boost TS22 Installation manual:
This device uses a thermal element which reacts to over-temperature water, pushing a valve on to the seat at the bottom of the booster cartridge.
In the event of a cold water failure this valve element reduces the output flow of the Trevi Boost to a trickle if the water exceeds 45C.
Perhaps try lowering your DHW temperature down from 65C (which seems high to me!?)
It also says:
If direct mains cold water pressure is greater than 3.0 bar, a pressure reducing valve must be fitted. If input conditions are minimal, then mixed shower temperature may only read 40C
(The 40C being your symptoms...)
Technogeek: Did you find a resolution. I am experiencing similar issues. The only thing left for me is dismantling the boost cartridge.
I am working through the diagnosis stages (all MI instructions followed to the letter).
The incoming cold water feed is 2 bar, when tested just before entering the trevi valve it is 14 litres per minute (tested through the shower head screwed onto the valve body). If I run a Full Rate Cold Water test via the mix exit using the same technique then the flow rate is 8 litres per minute i.e. I appear to loose 6 litres per minute flow rate when going through the valve! The MI instructions advise this test should be more like 14 litres per minute which implies minimal lose! I have cleaned everything possible to clean and wonder if a faulty boost cartridge.
Hot temperature at flushing nozzle = 65C (measured using a calibrated electronic meter at the hot flushing outlet)
Taken from the Trevi Boost TS22 Installation manual:
This device uses a thermal element which reacts to over-temperature water, pushing a valve on to the seat at the bottom of the booster cartridge.
In the event of a cold water failure this valve element reduces the output flow of the Trevi Boost to a trickle if the water exceeds 45C.
Perhaps try lowering your DHW temperature down from 65C (which seems high to me!?)
It also says:
If direct mains cold water pressure is greater than 3.0 bar, a pressure reducing valve must be fitted. If input conditions are minimal, then mixed shower temperature may only read 40C
(The 40C being your symptoms...)
I think this guy is on the money & your cold mains water pressure is borderline & your Hot may be too hot at 65C. It may need a pressure reducing valve?? Not sure why you increased the pipe size on the cold too 22mm???
Chasing Moonbeams mate, chasing Moonbeams. With the Laws of Physics there's always a reason it'll not work......We both don't know why but someone would. Many, many times I've been chasing moonbeams in the Plumbing trade & many, many times I've not seen the wood for the trees. But I love my trade, always a challange.
I cannot get my head around the fluid dynamics but maybe this is important (can anyone explain?).
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