Boiler Minimum Flow Rate

[cocjh1]

Reduce noise in my airing cupboard, which is basically a sound box in centre of the house.

Current pump is Grundfos UPS 15/50 with fixed bypass (gate) valve.

My thinking was to fit a variable speed pump to help reduce noise/vibration even further than just fitting a new pump...

 

[picasso]

Good idea, the noise from the boiler trying to get off the wall should drown out the noise from the pump.

 

[cocjh1]

Why would that be? The bypass would still allow flow, right. And it wouldn't be lit-off if there wasn't a call for heat and therefore zone value open anyway..

 

[picasso]

OK let us know how you get on.

 

[AGAS]

Ffs, just let him get on with it , you ask with your pump problem then get advice but your still going with your original decision, Jesus what's the point in asking in the first place . Just listen to Advice given ffs

 

[Phill Peck]

If the zone valves arnt open your pump shouldn't be running

 

[Agile]

What about minimum flow rate to protect against overheat, when the burner is off?

Why do you think that the boiler could overheat when the burner is off ??


It would also help us to give you the best advice if you told us what type of system you have based on the number and type of motor valves!

 

[Pin 5]

Why do you think that the boiler could overheat when the burner is off ??

Because boilers can overheat when the burner is off.

 

[Agile]

So how can they overheat when the burner is off?

 

[Phill Peck]

So how can they overheat when the burner is off?

To think you do this for a living and people take your advice is mind blowing.

The most common time for an over heat stat to trip in my experience is very shortly after the burner has gone off

 

[Agile]

The most common time for an over heat stat to trip in my experience is very shortly after the burner has gone off

Well that is quite true but is as a result of a fault ( or installation error ) condition preventing effective pump over run.

Not a normal boiler running condition!

 

[Phill Peck]

Well that is quite true but is as a result of a fault ( or installation error ) condition preventing effective pump over run.

Not a normal boiler running condition!

As is every boiler overheat situation!

 

[Agile]

But the OP in this thread seems to be asking his question in relation to a design aspect.

How he might measure the flow might be interesting though.

 

[ianmcd]

He could use an Oscilloscope connected to his listening stick

 

[Phill Peck]

Bottom line is you can only really buy variable speed pumps now but in this model it should be set to fixed speed.