Originally Posted by
DBMandrake
How is your pump controlled - is it controlled by the boiler or is it using a separate pump overrun timer ? It may just be pump overrun.
That sounds about right - that is 40% of the valve pin travel, that doesn't mean the valve is flowing 40%. Typically after the HR92 has had time to calibrate itself the "opening point" of the valve where water actually starts to flow will be at a reported position of around 40%, any less than 40% and the valve will not be flowing. More than about 80% is fully open with 40% to 80% being varying amounts of flow.
This does depend on the design of your TRV valve body of course - some valves have more or less operating range between closed and open than others but this is what I see with my valves.
That's going to depend entirely on your system and isn't really a function of the HR92 - all it does is opens the valve a certain amount. A bit more info about you system would help such as:
- How many radiators do you have
- Are they only noisy if one or two radiators are on and the rest are off ?
- Do you have an automatic bypass valve fitted in the system ?
If you've set the pump speed to low and you still get a lot of hiss my guess is you don't have an automatic bypass valve so when most radiators shut down there is a high pressure differential and the remaining radiators can hiss quite loudly if they are only partially flowing - just like a partially turned on water tap.
I think some designs of TRV valve bodies can be noisier than others under partial flow conditions as well.
I have an automatic bypass valve in my system set to about 0.4 bars and regardless of whether I set my pump to low or medium at most I only hear a subdued gentle hiss from any of my radiators, and I would never call it intrusive.