Noisy air source heat pump internally

youcancallmeal

I'm not talking the actual fan outside, that's fine it has a tolerable low hum and only when it gets up to full speed. My problem is with the internal system. There is an almost constant sound of what I assume is water being circulated through pipes. It's audible throughout the house and originates from the tank in the hot press. It does stop periodically and after much observation I believe it stops when the radiators come on or when someone is taking a shower(The water needs to be topped up and reheated). So I guess when it starts to do some work like heating radiators or domestic hot water thats when this 'flow' noise disappears which is kind of the opposite of what I would expect. Like late at night when the heating is in setback mode and the system should be idling it is still making the noise. I've tried playing around with all the options like turning off constant hot water but it doesn't seem to something I can control?

I've spoke to a friend who also has an ASHP and he says he doesn't notice much noise internally so I'm wondering does mine have a fault or is it just my tolerance for this kind of noise very low. It's a new build and I'm only living there about a month, I'm going to get on to the guys who installed it but just thought I'd throw it out here and see what other peoples experiences of internal noise is with heat pumps?

KCross

Heat Pumps works on the basis of giving a constant flow of heat to the underfloor/rads.

When the system decides to heat hot water for showers it would stop the underfloor/rads flow and switch the heat to the cylinder which explains the behaviour you see.


The thing is why you hear such a flow in every room. Typically heat pumps run with underfloor heating so you wouldnt hear it so maybe its because you have rads. If you open the valves fully on the rads does the noise go away? Maybe the valves are restricting flow and then you would hear more flow noise?

Another thing to look at is the manifold for the rads. Is the noise coming from that rather than the rads themselves? Maybe when all rads are "off" (i.e. not calling for heat) the manifold throws out more noise?

youcancallmeal

KCross wrote: »

Heat Pumps works on the basis of giving a constant flow of heat to the underfloor/rads.

When the system decides to heat hot water for showers it would stop the underfloor/rads flow and switch the heat to the cylinder which explains the behaviour you see.


The thing is why you hear such a flow in every room. Typically heat pumps run with underfloor heating so you wouldnt hear it so maybe its because you have rads. If you open the valves fully on the rads does the noise go away? Maybe the valves are restricting flow and then you would hear more flow noise?

Another thing to look at is the manifold for the rads. Is the noise coming from that rather than the rads themselves? Maybe when all rads are "off" (i.e. not calling for heat) the manifold throws out more noise?

Yes I get what you mean. I believe all the rads in the house have their valves fully open but will check later. I think the manifolds could be a likely culprit. I believe there should be 2 of them and they are in the hot press beside the tank. I would assume they are controlled by an actuator from the thermostats upstairs and downstairs. I must test out whether the noise disappears when the manifold is opened. The whole system has a 1 year warranty so will definitely be on to the supplier/installer about this.

youcancallmeal

Spoke with the plumber and think I've fixed it. So the pump on the pipe coming out of the tank is a Wilo Yonos Pico. There is an adjustable knob on it to set the differential pressure, it was set to max variable. I reduced it down to half and the flow noise has completely disappeared.

I don't really understand the difference between the modes of variable and constant differential pressure. I downloaded the manual and it does say that it should be "set to variable in heating systems with radiators, since the flow noises at the thermostatic valves are reduced." And for constant it "recommends this control mode for underfloor-heating circuits or older heating systems with large-sized pipes as well as for all applications with no changeable pipe system curve, e.g. boiler charge pumps."

I guess it being set to variable is correct but by reducing it to half of max I hope it doesn't have any ill effects? Hot water and radiators seem fine since I changed it so will just keep an eye on it. Supposedly an expert from the heat pumps manufacturer is due to come out to me in a few months to see how it's doing so I can query it with him then.

Cessee

youcancallmeal wrote: »

Spoke with the plumber and think I've fixed it. So the pump on the pipe coming out of the tank is a Wilo Yonos Pico. There is an adjustable knob on it to set the differential pressure, it was set to max variable. I reduced it down to half and the flow noise has completely disappeared.

I don't really understand the difference between the modes of variable and constant differential pressure. I downloaded the manual and it does say that it should be "set to variable in heating systems with radiators, since the flow noises at the thermostatic valves are reduced." And for constant it "recommends this control mode for underfloor-heating circuits or older heating systems with large-sized pipes as well as for all applications with no changeable pipe system curve, e.g. boiler charge pumps."

I guess it being set to variable is correct but by reducing it to half of max I hope it doesn't have any ill effects? Hot water and radiators seem fine since I changed it so will just keep an eye on it. Supposedly an expert from the heat pumps manufacturer is due to come out to me in a few months to see how it's doing so I can query it with him then.

Hi, could you post a picture of this knob please? Have the same issue here with ASHP using rads too. Cheers

youcancallmeal

Cessee wrote: »

Hi, could you post a picture of this knob please? Have the same issue here with ASHP using rads too. Cheers

Sorry only saw this now, I've attached the pic. I have it set just a little above 1 which seems to get the hot water around the rads and not make too much noise.

Cessee

youcancallmeal wrote: »

Sorry only saw this now, I've attached the pic. I have it set just a little above 1 which seems to get the hot water around the rads and not make too much noise.

Thank you! Hope this will solve mine too!

superblu

Just discovered this thread. Have this problem as well after carrying out a renovation on my house. Have been repeatedly told by the plumbers that this is just how it is with these rads. I am going to see can I fix it now myself.

youcancallmeal

You could try bleeding the rads, it's the first thing I did but it didn't help. Do you have thermostats as well? My house does for upstairs and downstairs but the heat pump technician said they aren't necessary, builders put them in because it helps get a higher BER. They only make sense for oil/gas heating. I was told to set the thermostats to 24 hours max temp(32 degrees), this way the upstairs and downtairs loops are constantly open and the heat pump isn't trying to push water into a closed loop which is also where a lot of my noise problems came from.

The whole system should be controlled by the heat pump control panel settings. I was instructed to set the temperature I want the house to be on the heat pump control panel minus about 5 degrees. So mine is set to 15 degrees and it works great, house is never too cold and the rads rarely get any more than lukewarm even when sub zero outside. I don't really understand why I need to set it around 15 degrees, the expert briefly explained to me the heat pump sends the warm water through the rads based on the temperature outside. This is all just my setup and what I've found works so it may be different for you.

EDIT: Also worth mentioning that the plumbers I originally talked to didn't really understand the heat pump system, it was only when the expert from the heat pump manufacturer came out did he explain how to troubleshoot and run the system properly. For example a friends elderly mother moved into a new build a couple of years ago which had a heat pump, after a year she didn't understand why her electricity bills were massive. It turns out the system had been setup wrong by the plumber and it was basically inoperative and was using mains electricity to heat the water and the rads for over a year. I believe her electricity bill in Nov/Dec was nearly 1k euro 😳

the_amazing_raisin

https://www.boards.ie/discussion/comment/118027163#Comment_118027163

I had an issue the past year or two with a loud humming/buzzing noise coming from the hot press. It sounded a lot like cavitation or turbulence in the pipes

Plumber came out and replaced the 3 way valve from a solenoid type to a rotary one. System is working much better now and no noises

I've a Dimplex A6M fwiw