Humming loud noisy potterton combi

[Harry Bloomfield]

So TRVs are supposed to be on the flow line not return? With the exception of bidirectional TRVs I read. My TRVs are Myson brand 2 way TRV. Is that bidirectional? How do you know which end is flow and which end is return? One side heats up quicker than other side when boiler is turned on is that the flow?

That is the flow end

 

[john2k]

Thank you. So basically I either need to move the flow pipe that's going into the left to right to go into the TRV and move the return pipe to the left. If pipes don't move then I will have to remove the valve at the radiator openings and swap them around? Do i use PTFE tape on the thread? I have plastic pipes going in like the pic below, are they push-fit? I'm assuming I press the sleeve in towards the valve and pull the pipe out? Are all the fittings re-usable? I don't need to replace any seals or anything?

 

[Harry Bloomfield]

So basically I either need to move the flow pipe that's going into the left to right to go into the TRV and move the return pipe to the left.

That sounded a bit Irish, so....

You can either swap the two valves completely over, one end for the other, or swap the two pipes over which feed the radiator, so flow becomes the feed once swapped. Usually the first method is much easier, but don't forget your system is full of water and may need to be drained down, or other arrangements made to prevent the escape of water. Once done, you may need to then top-up with inhibitor to prevent your rads rusting.

I will leave the experts on here, to answer your other questions.

 

[denso13]

So basically I either need to move the flow pipe that's going into the left to right to go into the TRV and move the return pipe to the left.

Not necessarily, it could just be a faulty TRV. Take a photo of the actual TRV.

 

[ianmcd]

just turn the valve so the sensor is now horizontal, or just remove the sensor as a temp measure

 

[john2k]

Not necessarily, it could just be a faulty TRV. Take a photo of the actual TRV.

Here's a pic of the TRV's that I have:

So since the pump was replaced, the case vibration noise and the constant humming has gone but I am now getting a really loud rather annoying noise that's really hard to explain. Basically when I turn the heating on, it is super silent unlike before BUT once heating has been on for some time and it seems maybe when boiler reaches a certain temperature it sounds like maybe a fan or something that's spinning like crazy speed and creating almost like a car revving sound. the noise is really annoying and the best way to explain it is almost like revving a car and this is on high rev. When I hear the noise, turning the thermostat down to trigger the boiler to turn off doesn't stop that sound straight away. Once again maybe a fan that has to cool something regardless of if boiler is on or off?

Also when it makes the noise it will make a noise for maybe 5 to 10 mins then stop then after a while start again. Almost like on a car when radiator fan kicks in

Any advice? I think i need to call back service engineer.

 

[MeldrewsMate]

TRV on the wrong end? Seriously? it's been like this since the property was built 11 years ago.

...and you now have a shiny new pump that will pump the water around your system much faster, exacerbating any TRV rattle problems.
Look up Bernouillis theorem, and the effect of fluid flowing through a restricted orifice (such as a nearly closed TRV)....Forget what setting it's on, the temperature of the room determines the orifice gap.

 

[john2k]

...and you now have a shiny new pump that will pump the water around your system much faster, exacerbating any TRV rattle problems.
Look up Bernouillis theorem, and the effect of fluid flowing through a restricted orifice (such as a nearly closed TRV)....Forget what setting it's on, the temperature of the room determines the orifice gap.

Thank you, these Myson trv says 2 way and I read that apparently they work on both flow and return. But regardless I think as good practice they should have installed them on flow. The problem with this noise issue is that my property was a new build around 11 years ago and this noise issue only started few years ago so for a good number of years it was silent. So if it was the TRV would it not having this noise issue all the time?

Although that one time adjusting the TRV slightly made the noise stop it didn't last for long and now when the noise comes, regardless of what I do to any of the TRV it still makes the noise. TRVs are on max open setting and the noise is coming from the boiler itself. Does TRV related noises come from boiler?

And finally one other thing that I've just noticed which Im not 100% sure about but seems to be so is that if I set my room thermostat to 22 degrees and allow the boiler to turn on and off based on the 22 degree room temperature then I have not experienced this noise yet at all. But if I set the room temp to 24 then at some point when either boiler or radiator temperature has reached some sort of temperature that's when it does that

 

[Gasguru]

Tell us what boiler model.you have.

 

[john2k]

Tell us what boiler model.you have.

Potterton ProMax Combi HE Plus

 

[Gasguru]

These boilers have a fixed speed pump that will be sized for the DHW output.
It sounds to me that as more and more of your TRVs shut down the reduced circulation is resulting in the differential pressure across the remaining valves becomming excessive leading to noise.
Although the boiler contains a spring loaded bypass valve that will open once the pressure is sufficiently high this is more for boiler protection.
You might consider fitting an external auto bypass valve across the flow and return.