Rattling noise from central heating pump

Bendy_House

FreeBear said:

You put one on the wrong end of the radiator didn't you

When you do that, they make a heck of a racket and it sounds like someone is hammering away at the radiator. A lot more noise than the OP is experiencing !

Och, it was a long time ago... :-(

What was funnier was the sudden 'clunk' when TRV closed down enough so the flow actually slammed the rattling washer fully shut. And then it would be reluctant to reopen against the flow...

Steep learning curve :-)

NSG666

Graeme1978uk said:

NSG666 said:

With the other two zones off, does the noise start as soon as the master bedroom zone turns on or only after a period of time? Where is the thermostat for this zone? Do the rads have TRVs on them?

When it's chattering does it stop as soon as you turn on another zone?

Yeah the noise starts as soon as zone switches on. The thermostat for this Zone is in the master bedroom and is a Tado wired thermostat.

Out if the 3 rads on this zone, only the one in the en-suite has a TRV on.

Sod’s law, I’ve just activated this zone to see if it stops when another zone is active, and the noise didn’t start when the heating kicked in, but I think it does to it intermittently anyway maybe. Next time it’s making the noise I’ll kick another zone in and see what happens.

Just for other contributors who might be more knowledgeable than me I was wondering whether it was the bypass valve which is just above the pump and possibly doing more work when only the small master bedroom circuit is in use.

That said isn't this all still under the developer's guarantee so for them to diagnose and rectify?

Bendy_House

The OP reports that 2 of the three rads on that zone don't have TRVs, so presumably are left partially open (are all rads 'on' to some degree, Graeme?)

And that Wilo looks like a 'Smart' version, so - if set to 'auto' - should manage its own speed to match demand. Can you confirm the model, Graeme, and what setting it's on?

Since you have a good audio clip, I'd email Wilo the link and ask them.

coffeehound

NSG666 said:

Just for other contributors who might be more knowledgeable than me I was wondering whether it was the bypass valve which is just above the pump and possibly doing more work when only the small master bedroom circuit is in use.

That's an interesting point.  The sound is just like the fluttering a TRV makes when the pump switches off, so could it be a sort of oscillation between the bypass and the TRV which is alternately causing the TRV to open and close?  Taking the TRV head off would show whether it's involved as a quick check

Graeme1978uk

NSG666 said:

That said isn't this all still under the developer's guarantee so for them to diagnose and rectify?

Yes and no.

We've been in just over 12 months, the terms of the guarantee on the central heating system is that we pay to have it serviced each year, and they will be responsible to rectify any problem, but in the first instance I have to get it assessed to ascertain what the issue is and they will rectify.

Graeme1978uk

Bendy_House said:

The OP reports that 2 of the three rads on that zone don't have TRVs, so presumably are left partially open (are all rads 'on' to some degree, Graeme?)

And that Wilo looks like a 'Smart' version, so - if set to 'auto' - should manage its own speed to match demand. Can you confirm the model, Graeme, and what setting it's on?

Since you have a good audio clip, I'd email Wilo the link and ask them.

I've attached a photo of the pump whilst it's running the zone in question. The noise has stopped currently but as I said it does tend to come and go.

Bendy_House

Ah, interesting...

I'd try switching it to the first graph type - Differential Pressure Variable. That's seemingly the best choice for 2-pipe systems - as you have - where the flow demand will change as TRVs open and close.

The setting it's currently on is 'constant speed', and I notice is set to 'max' of 3.

Whoever fitted this smart circulator wasn't. drrrrr-cheeesh.

https://cms.media.wilo.com/cdndoc/wilo194169/5238858/wilo194169.pdf

The 'fault signal' (triangle) LED also appears lit, but I don't know what it's referring to.

Graeme1978uk

Bendy_House said:

Ah, interesting...

I'd try switching it to the first graph type - Differential Pressure Variable. That's seemingly the best choice for 2-pipe systems - as you have - where the flow demand will change as TRVs open and close.

The setting it's currently on is 'constant speed', and I notice is set to 'max' of 3.

Whoever fitted this smart circulator wasn't. drrrrr-cheeesh.

Honestly, utter cowboys. Off the top of my head....

1. Hot water pipe plumbed to one toilet

2. Durgo valve not fitted behind bathroom wall giving us sewage smells for ages until we figured out why. They hadn't put an inspection door in either so the wall had to be cut into to rectify

3. Central heating didn't work on day 1 because of crossed pipes

4. When that was resolved, when the water was being heated, hot was going into 7 of 16 radiators. We didn't notice until the summer because in the colder months the heating was on a lot of the time anyway. Only when it warmed up and we were sweltering did we realise some rads were hot.

5. En-suite shower tray doesn't drain properly and creaks like you wouldn't believe, not supported underneath properly, awaiting that to be replaced.

6. When I had the boiler serviced for the first time in November, he said where he inserts his probe underneath, the screw was very loose and there would have been a tiny gas leak the entire time.

Bendy_House

Graeme1978uk said:

Honestly, utter cowboys. Off the top of my head....

1. Hot water pipe plumbed to one toilet

2. Durgo valve not fitted behind bathroom wall giving us sewage smells for ages until we figured out why. They hadn't put an inspection door in either so the wall had to be cut into to rectify

3. Central heating didn't work on day 1 because of crossed pipes

4. When that was resolved, when the water was being heated, hot was going into 7 of 16 radiators. We didn't notice until the summer because in the colder months the heating was on a lot of the time anyway. Only when it warmed up and we were sweltering did we realise some rads were hot.

5. En-suite shower tray doesn't drain properly and creaks like you wouldn't believe, not supported underneath properly, awaiting that to be replaced.

6. When I had the boiler serviced for the first time in November, he said where he inserts his probe underneath, the screw was very loose and there would have been a tiny gas leak the entire time.

Quality!

Can you have a read of the Wilo instructions, and give shifting to DPV a try? Nothing to be lost by trying this - a few presses will get you back to where you were before.

Even on the 'constant speed' setting, '3' is usually only required on very large systems. Best to have the pump set to the min that does the job - less wear, less noise, less consumption.

Le_Kirk

They do hide their instructions away from prying eyes! Eventually found this: -
https://cms.media.wilo.com/cdndoc/wilo189132/4259770/wilo189132.pdf
Page 33 shows that solid green light on indicator #8 is normal running condition whilst if it flashes there is an error.  Page 48 deals with faults but is not very detailed.