Motorised valve clicking/ticking noise

r4w

Hi, in my new home I have a couple of Danfoss hpa2 valves that I believe are used to separate the heating of the master bedroom with the rest of the house.
I have two Tado smart thermostat that are working with the system.
However, whenever I hear the Tado's relay switch off the heating as it reached the temperature (the boiler is from Ideal), the two valves starts to clicking/ticking until the boiler goes completely off.
I'm wondering if this is normal or if I should raise this with the builder.
Thank you in advance

Alex1983

Probably pump pressure against the now closed valves. S plan systems which yours sounds like are should have a bypass pipe. Maybe you don't have one or not adjusted correctly.

r4w

Thanks Alex, I have made a short video, just in case it could shed more light (I had to detach the URL in order to post it): https /youtu.be/ywXhE5Qp550

Le_Kirk

Here is your link made live: -
https://youtu.be/ywXhE5Qp550

r4w

I have also taken some complete photos of the system, is the pipe below the bypass one?

https /ibb.co/g0udZK
https /ibb.co/bWgsuK

Le_Kirk

Your links made live: -

https://ibb.co/g0udZK
https://ibb.co/bWgsuK

Rodders53

Pipe on left (with drain down valve) = heating flow
To two motorised valves (outs on top to heating circuits x 2)
To Bypass Valve operated via pressure of flow water.
To bypass return to boiler via pipe on right.

Looks like a bit of a small leak (white bloom) on the Bypass valve inlet.

The motorised valves make more noise when closing than opening (the manual levers on the bottom will simulate the noises of opening and closing... is that the sound you hear?

The valves have microswitches inside to call for heat from the boiler when they are fully opened by the motor, that can be heard as a click. They operate again as soon as the valve starts to shut under a mechanical return spring. Are those the clicking sounds you hear?

Note 1: the microswitch is not always operated when using the manual lever. You have to usually lever it across quite fast to do that.
Note 2: the manual lever is designed to part-open the valve for system filling, so there is a 'slot' that it can be held by at about halfway. The motor will free off the lever when it operates if left in that position so it will then close properly when.

Bypass valve will open under pressure if the boiler pump has an 'over run timer' and both motor valves are closed... Hot water will then flow back towards the boiler via that otherwise cool pipe on the right. That may cause the pipework on right to heat up and expansion/contraction can cause a noise like ticking... is that what you hear?

r4w

@rodders53 thanks for the detailed explanation!
There is a youtube link a little above with the sound I'm getting.
Builder's plumber came around my house this morning and spoke with my wife, it seems they're looking to replace the T joint/bypass valve tomorrow as it seems it's the issue.
I believe your last possible cause of the tickling may be right, I will provide more details and hopefully a resolution tomorrow!

r4w

Apologies for the delay but I got this fixed just few days ago (along with other things) and basically the plumber has replaced the bypass tube with another and that noise disappeared!

Once again, thank you for all your replies, they were all useful