Why does my pump get noisy when rads are turned off?

[Last Triumph]

Sorry guys, on my first post, I meant the stat on the cylinder.

Noise is definately the pump - no question. You can hear the drone throuout the house, and as soon as you open the airing cupboard door, it's right in your face.

Not sure what a fully pumped system looks like, but the pump feeds a two way honeywell valve. One 22mm output feeds the rads, the other 22mm feeds the input of the heating coil in the middle of the cylinder. Interestingly (?) the output at the bottom of the cylinder is only 15mm and returns directly to the boiler in the kitchen.

Pump isn't knackered as it runs silently when the tank stat is turned down.

The noise is a combination between a droan and as if air is trapped in it although it is vertically mounted...

Can't imagine there is too muh junk in the system as it has been drained a few times in the last 12 months to service rads etc.

 

[Doctor Drivel]

You'll need a differential by-pass fitted:

He doesn't . He may have a gravity DHW system which mean the boiler is not require fully pumped, so fitting a Wilo Smart pump (about £44 from s/fix) or a Grundfos Alpha will reduce noise and electricity usage. Even if fully pumped it will work well too. It automatically adjusts speed to pressure in the system. The more pressure the less the speed. Well worth getting in many systems.

The pump is a direct replacement for the existing unit - a DIY job. No pipes to cut, etc.

 

[JohnD]

but

...the pump feeds a two way honeywell valve. One 22mm output feeds the rads, the other 22mm feeds the input of the heating coil in the middle of the cylinder...

 

[Doctor Drivel]

but

...the pump feeds a two way honeywell valve. One 22mm output feeds the rads, the other 22mm feeds the input of the heating coil in the middle of the cylinder...

A Wilo Smart or Grundfos Alpha, as I said, will still do the job. As long as all the rads are never off at the same time.

 

[Last Triumph]

I'm a bit confused to be honest and still can't figure out why my pump is noisy when the rads are turned off or the system is programmed to water only etc

 

[Last Triumph]

Whilst the pump was droaning away last night, I turned the wall stat in the hall down low to see if it switched the pump off but it didn't.

Does that in anyt way help establish the nature of the system?

 

[JohnD]

I'm a bit confused to be honest and still can't figure out why my pump is noisy when the rads are turned off or the system is programmed to water only etc

Because the pump is also circulating to the cylinder like you said

Last Triumph wrote:
...the pump feeds a two way honeywell valve. One 22mm output feeds the rads, the other 22mm feeds the input of the heating coil in the middle of the cylinder...

 

[Last Triumph]

Right then - so I've got a fully pumped system with a crude hit and miss bypass for when the system is run on 'water only'

Which is noisy because it's working too hard with the bypass closed?

 

[Terrywookfit]

Where is the cold feed and vent pipe in relation to the pump??
Could it be pumping over when flow is restricted to H/W ??
Or even sucking air in the vent!

 

[Last Triumph]

The pump is vertically mounted from a T piece that joins the supply / vent tube about half way up the airing cupboard. The feed / vent pipe then goes about 5 feet up into the loft and into the top of the header tank

 

[Terrywookfit]

Is it pumping towards the vent pipe or away??
If its pumping away try sealing the vent pipe with your hand and see if there is suction! Alternatively try extending it below the water line (temp) and see if the noise stops!!
If its pumping towards vent ,does water discharge into tank!!

 

[billyo]

tell you what if you need a pump dont go to plumbcenter if you do and you take the pump out of the box, even to to look at it you will now own it, and if they do take it back at manager discretion they charge 25% re stocking happen to me yesterday (dick turpin wore a mask) plumbcenter do it bare faced,
I look forward to this company going ti*s up

 

[Terrywookfit]

tell you what if you need a pump dont go to plumbcenter if you do and you take the pump out of the box, even to to look at it you will now own it, and if they do take it back at manager discretion they charge 25% re stocking happen to me yesterday (dick turpin wore a mask) plumbcenter do it bare faced,
I look forward to this company going ti*s up

Are you still going on about that Billyo ??
STOP WHINGEING!! next time make sure you order right thing!!

 

[billyo]

if i can stop plumbcenter ripping you good people off, i will make sure everybody hears pass it on, and dont let big business take working class money for nowt we may not all have terrywookfit dosh to squnder

 

[Dan Robinson]

I think you'll find there is a dirty great notice up in the shops saying that return are at the discretion and with a resotcking fee.

It'll hopefully teach you to buy the righgt stuff in fture - we have to.