Honeywell Automatic Bypass Valve noise

[kofi2003uk]

hi,
need some advice please. i have 16 radiators on an open vent system for heating. hot water is unvented. all radiators have TRVs except 2. however i plan to add a TRV to one of the 2 so i have only 1 rad with no TRV. hopefully more energy efficient that way.

Currently works fine with all radiators getting hot except noise from ABV, when TRV's start closing down. please see video

i believe the ABV is a honeywell du145. is that correct from the video?

now my question is how do i stop the noise or at least make it less noisy? is the ABV set incorrectly?

also the numbers on the dial currently 2. does a higher number let more water through or less? am thinking that if i probably let more water through the noise will stop? i have no experience with these so not sure which way is which.

your advice is appreciated. thank you

 

[Madrab]

also the numbers on the dial currently 2. does a higher number let more water through or less? am thinking that if i probably let more water through the noise will stop? i have no experience with these so not sure which way is which.

No - numbers would usually equate to pressure in Mbar/bar - that being the pressure against the valve needed for it to start to open, s a lower number means less pressure needed to open the valve. That noise is more indicative of a fouled valve, may need removed and cleaned or replaced.

The ABV can be opened more to let more water through if system noise is a problem though it really should be setup specifically with the pump and system requirements etc to ensure that the bypass actually works at the correct point. This is to ensure the pump doesn't run against a closed head and the boiler has a suitable flow when the TRV's start to shut down but stops the ABV from opening too early which can be inefficient and cause an imbalance in the system.

Honeywell ABV

 

[kofi2003uk]

thank you Madrad. am i right in thinking an even lower setting of say 2 will open with even less pressure. that is as soon as a few TRV's close, the ABV will open to let water by? am thinking this may reduce the noise or have i got this wrong? thanks

 

[Johntheo5]

Your pump Head is possibly too high, can you post the make/model/mode & its setting or post a photo of it running with the LEDs clearly shown.

 

[kofi2003uk]

please see below. Boiler Vailant ecotec plus 418

 

[Johntheo5]

Thats your problem almost without any doubt, the UPS3 is a giant of a pump and is dispatched set to full speed, III on CC3, it will be circulating at a massive head of 6.4M up to a flowrate of over 19LPM, 1.15ms/hr.
Just press the setting button briefly a few times until you gret just one solid green LED, I on CCI, the pump head is then reduced to 4.2M head which should be quite aqequate for your needs and will certainly reduce the noisy operation.

How many rads??.

 

[kofi2003uk]

thank you .

i have 20 rads all together. 3 rads in 1 zone and 17 rads in rest of house. 9 tado x smart radiator thermostats, 9 TRV's with 2 on no TRV's. 4 of the TRV's are hardly opened as we dont use those rooms so are closed most of the time on frost protection. Thank you

 

[Johntheo5]

You should still be OK at that setting, if all rads not heating or very slow then press the button to get one green + one orange LED, that gives a 5.2M head and hopefully not too much noise, I would also increase the ABV index setting to ~ .35 to .38 (3.5M to 3.8M) after reducing to speed I, if you have to increase to speed II, increase the ABV index to 0.45/0.48.

 

[kofi2003uk]

(3.5M to 3.8M)

many thanks for your help. is 3.5M - 3.8M corresponding to 3.5 on the ABV dial above in the picture? thank you

 

[Johntheo5]

That's correct, yes, the index is in meters, M, I thought they were in (decimal) bar.

 

[kofi2003uk]

thank you so much. i will reduce pump speed to 1 green only and see how i get on. much appreciated.

 

[kofi2003uk]

sorry me again and am sure this is a silly question. turning the ABV clockwise is increasing it, right? and anticlockwise is decreasing it, am guessing.
i just found out that unscrewing the screw on the ABV does not turn allow me to turn the spindle and the numbers plate inside just wobbling around. so i suspect that 2.5M it was showing probably isnt correct to start with. had to unscrew it all the way and the cover and numbers thing comes right off. probably messed up there lol
i have made a note of the current setting with a marker on the spindle so i know how many turns back and forth its currently set at.

3.5 full turns anti clockwise takes it to the stop position and 8.5. full turns clockwise takes it to the end stop. so i can reset it to where it was if necessary

to increase to 3.5M, am guessing i need to turn clockwise ? i will start with one full turn clockwise if indeed that is the way to increase the pressure point at which the valve opens.

thanks for your patience .

 

[Johntheo5]

Not familiar with the 145 but clockwise yes to increase the lifting head.

 

[Johntheo5]

There is a problem with using a ABV (automatic bypass valve) with most modern A rated circ pumps in that the pump head doesn't fall off rapidly when the flow demand increases or more importantly doesn't increase rapidly when the flow demand (like zone valve or TRVs closing) decreases, you can see below using the DU144 as a example (easier example to see what I mean, than in the DU145)), but the UPS3, while a fine powerful pump is particulary "bad" because it doesn't really have true fixed speed curves, they are, in effect, to all intents, 3 constant pressure curves, see post #6, above. You are probably better off with just a manual gate (as a bypass) valve and just suffer a small but controlled recirc at all times, the DU145 or any ABV give a huge bypass, virtually "uncontrollable" leading to lower boiler efficiency as the return temperature rises. Sometimes a towel rad or say one small rad is plumbed in to be always in the system so that there is a bypass circuit when all zone valves shut, is any one of your rads/towel rads configured luke this?.

Is this a relatively new install using the UPS3 or did the UPS3 replace the original pump?

 

[Madrab]

That's correct, yes, the index is in meters, M, I thought they were in (decimal) bar.

Don't meant to disagree but .....

The 145's differential (delta) pressure scale is in mbar/bar, not M head