How can I check if my pressure pump is working ?

[Jackrawlings]

Hi Guys ,

Had a valliant engineer out as I could not add any water to my boiler and it’s sitting on 1bar when I used to have more than this and could easily top the boiler up with the two switches underneath. I live on the fourth floor and when I moved in we had a brand new
GRUNDFOS Type UPA15-90 N 160 pump fitted (see picture) when I moved in 5 years ago . Is there any way I can check if this has now broken ? 5 years seems not a long time for it to stop working . I’ve been told I should be getting more than 1 bar and I’m certain I used to get more water pressure than this so it all leads to the pump but I want to make sure before I pay for a plumper to come plus the pump is around £300. It also could be a problem in the area but it’s been like this for months .

I’ve noticed on the top of the pump there is 3 settings and it looks life the dial is switched to off but I have never touched it is this correct ? See attached photos

 

[Last Plumber]

If you are on the 4th floor it is likely to be the water pressure is only reaching the 1 bar you have. The water board only has to provide just over that at ground level in most areas, as far as I am aware.

 

[snowhead]

As L-P, it's the mains water pressure that determines what pressure you can get at the boiler, not the pump.

It's likely either something has changed in the building re water distribution or people are using more water at normal times or there's been additional users outside the property.

Try topping up after midnight when most people are in bed / not showering etc.

Other problems might be, the presure gauge /sensor is faulty and the actual pressure is higher,
Or there's a faulty Pressure relief valve that's discharge at over 1barbut closes below 1bar.

 

[Jackrawlings]

But if the pump adds 0.4 - 0.6 extra pressure and this is attached to the mains water for the flat wouldn’t it run through this then into the boiler ?

I will try topping up later thanks for that tip

I can hold my hand over the tap without it spraying out so I don’t think the pressure gauge is faulty I generally think it’s the pressure but I thought it used to be stronger than this which is why I’m worried the pump has broken but I don’t know how to diagnose this exactly .

As L-P, it's the mains water pressure that determines what pressure you can get at the boiler, not the pump.

It's likely either something has changed in the building re water distribution or people are using more water at normal times or there's been additional users outside the property.

Try topping up after midnight when most people are in bed / not showering etc.

Other problems might be, the presure gauge /sensor is faulty and the actual pressure is higher,
Or there's a faulty Pressure relief valve that's discharge at over 1barbut closes below 1bar.

 

[John.g]

But if the pump adds 0.4 - 0.6 extra pressure and this is attached to the mains water for the flat wouldn’t it run through this then into the boiler ?

I will try topping up later thanks for that tip

I can hold my hand over the tap without it spraying out so I don’t think the pressure gauge is faulty I generally think it’s the pressure but I thought it used to be stronger than this which is why I’m worried the pump has broken but I don’t know how to diagnose this exactly .

That pump has 3 settings, I which is Off, II which is Auto (should start/stop automatically with a demand for water) & III which is Manual where the pump runs continuously, presume the relevant LED will illuminate whatever mode is selected, suggest III, you should hear the pump running, on setting II you should hear it running once you open a tap, I would suggest setting III (Manual) for boiler top up.
This pump requires a minimum inlet pressure of 0.2bar (2.0M) to prevent cavitation and deliver its minimum boost, so if your mains pressure is as low as this (on the 4th floor) then the maximum boost or the maximum boiler pressure you can achieve is 0.9bar. I would top up when the boiler is cold which may not be at night where the mains pressure/boost should be at the highest.
You should certainly achieve a boiler pressure of 0.9bar as there is practically no flow required at this head for topping up.

 

[Jackrawlings]

That pump has 3 settings, I which is Off, II which is Auto (should start/stop automatically with a demand for water) & III which is Manual where the pump runs continuously, presume the relevant LED will illuminate whatever mode is selected, suggest III, you should hear the pump running, on setting II you should hear it running once you open a tap, I would suggest setting III (Manual) for boiler top up.
This pump requires a minimum inlet pressure of 0.2bar (2.0M) to prevent cavitation and deliver its minimum boost, so if your mains pressure is as low as this (on the 4th floor) then the maximum boost or the maximum boiler pressure you can achieve is 0.9bar. I would top up when the boiler is cold which may not be at night where the mains pressure/boost should be at the highest.
You should certainly achieve a boiler pressure of 0.9bar as there is practically no flow required at this head for topping up.

View attachment 94367

Hi there
Thanks for the reply ,

Can you see on my picture that I think the dial is pointing to off ? Or have I got this totally wrong ? Is the little grey dial on top easily switched around ? I didn’t want to touch it and mess anything up .

 

[John.g]

Hi there
Thanks for the reply ,

Can you see on my picture that I think the dial is pointing to off ? Or have I got this totally wrong ? Is the little grey dial on top easily switched around ? I didn’t want to touch it and mess anything up .

I can't actually see that dial but why not try it, it can't do any harm? it can't be for anything else.

 

[John.g]

Had another look on my laptop and can see now that the rotary switch is pointing to I, Off, just switch it to III, if pump doesn't start then either a elec supply problem or a pump problem.

 

[Last Plumber]

What you are seeing when the pump starts is a rise in pressure at the point where the gauge connects into the heating system as the water circulates. The 0.2 bar rise is what I would expect you to see. That is not the same rise as when you put water into the system via the filling loop although it is indicating a pressure change in the same water. The rise when the pump runs is due to the circulating head of the pump and the rise from the filling is due to you increasing the volume of water in the system.
Hope that makes sense?

When the rise is shown as the pump runs, no water is entering the system.

 

[John.g]

What you are seeing when the pump starts is a rise in pressure at the point where the gauge connects into the heating system as the water circulates. The 0.2 bar rise is what I would expect you to see. That is not the same rise as when you put water into the system via the filling loop although it is indicating a pressure change in the same water. The rise when the pump runs is due to the circulating head of the pump and the rise from the filling is due to you increasing the volume of water in the system.
Hope that makes sense?

When the rise is shown as the pump runs, no water is entering the system.

Switching on the booster pump should certainly enable topping up the boiler pressure to at least 0.9bar and even further if the mains is even 0.5bar.

 

[Last Plumber]

Switching on the booster pump should certainly enable topping up the boiler pressure to at least 0.9bar and even further if the mains is even 0.5bar.

Apologies..
I have misunderstood this thread from the beginning.

I thought the OP was confused. I glanced at it and thought @Jackrawlings was talking about a domestic circulator.
I also think @snowhead was on the same page as me.

Very sorry if I mislead the OP. I will read pump model more closely in future.

 

[John.g]

@Jackrawlings. Have you got the booster running and topped up your boiler?

 

[Jackrawlings]

@Jackrawlings. Have you got the booster running and topped up your boiler?

It was very hard to get to the switch on the top because whoever fitted the kitchen unit has stuck mdf flush up against it . I tried to push it with a screwdriver but the switch isn't moving and I couldn’t find any videos on YouTube of anyone turning the switch so I don’t know how hard it needs to be pressed so didn’t want to put any more force on it than I already was because it didn’t feel right .It seems odd whoever fitted it 5 years ago wouldn’t have even switched it on.

 

[snowhead]

Apologies..
I have misunderstood this thread from the beginning.

I thought the OP was confused. I glanced at it and thought @Jackrawlings was talking about a domestic circulator.
I also think @snowhead was on the same page as me.

Very sorry if I mislead the OP. I will read pump model more closely in future.

I realised there was a slight mix up after I posted and looked closely at the Stainless boost pump, (should have realised with it being red) but the O.P mentioned Vaillant engineer and topping up the boiler so I was on the wrong page as L-P.

 

[John.g]

It was very hard to get to the switch on the top because whoever fitted the kitchen unit has stuck mdf flush up against it . I tried to push it with a screwdriver but the switch isn't moving and I couldn’t find any videos on YouTube of anyone turning the switch so I don’t know how hard it needs to be pressed so didn’t want to put any more force on it than I already was because it didn’t feel right .It seems odd whoever fitted it 5 years ago wouldn’t have even switched it on.

Is there room enough to grip the selector knob with one of those adjustable wide jawed "pliers"?(can't think of the correct name), you need to be able to do this IMO as the screwdriver could damage/break the switch. Can you get a better photo?.

 

[Jackrawlings]

Is there room enough to grip the selector knob with one of those adjustable wide jawed "pliers"?(can't think of the correct name), you need to be able to do this IMO as the screwdriver could damage/break the switch. Can you get a better photo?.

there’s no space for any leverage it’s hard enough to get my phone in there for a photo let alone some pliers .

 

[John.g]

That seems to be pointing to II Auto?? which would make sense on installation. Can you open a tap fully (or get someone) you should feel/hear the pump running if still working in this mode.
If this is the indicator then you might (if not allready tried) be able to push this to the left with the screwdriver to position III, Manual.

 

[Jackrawlings]

That seems to be pointing to II Auto?? which would make sense on installation. Can you open a tap fully (or get someone) you should feel/hear the pump running if still working in this mode.
If this is the indicator then you might (if not allready tried) be able to push this to the left with the screwdriver to position III, Manual.

Ahh yes it’s has the number 2 on it on that little dial sorry I was assuming the arm position was what the setting it was on . I can’t hear the pump switch on when I turn the water on .

 

[John.g]

You can, as suggested, top up at night/very early in the morning with a cold boiler if possible via just the mains.
The only other thing you can do with that booster (if you want it working in Auto) is to see where its electrically fed from and see if any MCB is tripped or blown fuse or else get it looked at.