I just had my new system reconected properly and they put the desuperheater into use. They said I should expect a slow climb to 80-90F domestic water. I expected better and certainly got it. I have a unit that heats air and water for infloor, which also has separate desuperheater coil. After a few hours of the compressor running to heat my infloor side . . .my 60 (imperial) gallon domestic storage tank was circulating at 150F. There is a temp sensor which is designed to shut my compressor down if if passes 130F . . but is doesn't seat properly on the copper so likely wasn't sensing full temp. I opened my hot water faucet which injected cold in order to lower the tank temp and then turned down the infloor thermostats so the compressor would shut down sooner. What is the solution for getting very high water temp in the closed passive desuperheater loop if the forced air or infloor are calling for heat (or cool) for very long periods of time? If I'd tried to push the infloor thermostats to higher temps and let the floor run for several hours . . i don't know where (or if!) the desuperheater would have levelled off!!??