Smart TRV whistling
I've tried bleeding the rad with no success. Without being able to adjust the rate of flow through the TRV I can't think of another solution to this problem. Can anyone suggest one, or evert just make sense of why this is suddenly happening?
Best Answer
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Try slightly adjusting the lockshield valve on the other side. Wait until the rad is whistling then turn it up or down just a fraction.1
Answers
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Thanks I'll give this a try
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Did this help ?
I also experience that most probably when the valve is barely opened it gives whistling noise.0 -
It did help, but only if I turn the lockshield valve almost to closed. As its on the end of the loop I'm worried it will limit the heating but it seems to be coping so far. Still find it weird that this only happened after the switch over of TRVs, and also weird that whistling radiators seem such a poorly understood thing for something so mundane!0
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Have you checked your pump speed?
It could be, that when some valves are closing, the flow rate is getting too high.
If you have a combi boiler, I don't believe there's much you can do about it (boiler controls pump), but if you have a heat only boiler with separate cylinder, you could possibly try turning the pump down (depending on your pump).
The likely reason this has surfaced since swapping to tado is your old TRVs were probably operating proportionately (never fully closing), whereas tado could be reducing your system size by shutting down rads.
If possible, give it a try, although you may find that the furthest rads don't heat as quickly as you like, or you get boiler cycling when heating water (if a system rather than combi), in which case, put the pump back to where it was.
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A whistle (or more accurately a trumpet-like sound) is quite common with some TRV valve brands when the hot water flow direction through the radiator is the wrong way around and at the very treshold of opening/closing the valve. I'm not sure this sound will manifest itself also with TADO TRVs hooked up to such a valve or not.
(The right direction of the water flow is hot water entering the radiator from the side where the TRV is connected, and (cooler) water leaving the other end.)
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What about lower the pressure in the system a little ? Would that help?
I noticed that I need to fully open the non-smart valves and then mostly the whistling dissapear on the smart TRVs, however this means I need to always heat spaces at full power which normally I would not want (e.g. garage).
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@Valaki1234 - Possibly. It rather depends on the current system pressure, which could be too high (1-2 bar max is recommended).
You're onto the cause when you refer to opening the other valves. The system gets smaller with every TRV that closes, and tado TRVs are being used by most people to micro-zone systems (on/off) as opposed to using manual TRVs at a constant set temp (which is the intended use of TRV valves - constant circulation, in fact).
Once the system gets smaller, the flow rate driven by the pump becomes too high, unless the pump is fully automated to maintain constant pressure and flow (as opposed to fixed speed). Automatic bypass valves (ABV) should otherwise be installed to address this issue, by returning water through the primaries when needed.
Try setting TRVs lower in less-used spaces, but not off, and for smart TRVs, don't schedule off periods. Don't micro-zone - e.g. have a generally uniform set temp by living spaces (18-20) and by bedrooms (16-18).
It may sound counter-intuitive to energy efficiency (and contrary to what the likes of the Energy Saving Trust - and soon the Government - is telling us), but unless your internal structure is super-insulated, all you're doing by switching rads off, is increasing the heat demand from the rads that are on, because the heat from the heated rooms is pulled to the unheated rooms. In turn, that mean you need those rads to run hotter to heat the space (i.e. a higher boiler flow temp), thereby cancelling out the 'turn off unused rooms' efficiencies. A bit lower, yes. Off, no.0 -
Hello, as others have mentioned, if more TRV's are on a system or if more TRV's are closed but the pump is still pumping away full force then the noise of the pump could sound like gushing through any of the TRV's which are still open.
A modulating smart pump like the Grundfos UPS3 or Grundfos Alpha or some of the Wilo ones could 'back-off' it's output if it went from 10 rads to 2 or 16 to 7 in response to the resistance of the system it's pumping through.
The hissing noise will be either a pump setting issue, a balancing issue or a bypass or auto-bypass issue. It's a pressure noise through a small orifice.
Some recent combi boilers like Vaillant for example allow the pump operating mode to be adjusted in the parameters. Allowing it to be made to pump harder or softer in different modes. If controlled electronically via ebus or Opentherm or their own bus network then many new boilers modulate the pump very accurately as well as the flow temperature.
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