I recently had a new gas boiler fitted on my open vented system. there was a slight modification to the outside of the heating loop through the DHW cylinder but the DHW supply plumbing was untouched and the flow rate through all the hot taps is unchanged.
My Trevi Boost shower has stopped working though, after being fine for
3 years. I've flushed and cleaned it out but it's still running stone cold at all settings.I've now noticed that the pressure of the cold supply is reversing the lower pressure hot supply and sending cold water back along the hot pipe.
I see from the installation instructions that there should be non- return valves on each supply pipe. There isn't currently.
Of the 4 recommended check valves in the Trevi installation guide, non were available via Web searches. The only references to them were in on-line versions of the Trevi Boost installation guide.
Thinking about alternative valve sources, I couldn't help wondering how, with both incoming water pressures being quite consistent, why wouldn't the same pressure conditions that forced cold water down the hot pipe when there is no check valve, not just stop the hot water from entering the mixer when there is a check valve?
Dick Treen