Hi, (Mods, if this should be in another sub forum please let me know) I've been running a Navien 240S on demand water heater for about a year in my house. Apart from having to wait for the heat at the shower it worked great. I'm doing a reno though and have added a couple bathrooms, and with weak city water pressure (I have 3/4" from the city) I was looking for a way to keep decent pressure across multiple taps (I have a manifold controlling each floor of the house). After some research and calling around I settled on the Grudfos Scala 2. I've got it installed now and pressure is excellent. However, the pump seems to have introduced a new problem whereby the water temperature now fluctuates quite significantly during a shower. (I should add that I have 20L - 12 gallon - how water buffer tanks for two of the floors in the house and the problem is only noticeable on the floor without a buffer tank) Previously the hot water was dead consistent for as long as you'd like to run it. Now it goes up and down, like in a wave pattern, easily dropping 10C for 20 seconds or so before returning to set temperature. I haven't found anything in the literature for either the pump or the water heater so now I'm casting about hoping someone will have some insight. Many thanks!