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Just in case you didn't follow that, and I'm not sure I did, here is another very rough explanation of PP as explained to me by a Grundfos engineer.

Very basically, a pump could run faster and slower to maintain the same available head as rad valves are open and shut. When a valve is opened, more water can flow so the pump runs faster to maintain the same pressure. This would be a constant pressure setting.

Proportional pressure slightly over-compensates, so as the flow increases when you (or a TRV) open the flow to a rad, the pressure at the pump is not only maintained by increasing the pump rotation speed, but the pressure is actually raised a little. The reason for this is that the primary circuit (the pipe from the boiler to the motorised valve and the common return to the boiler) creates more drag when the water velocity is higher. So if the pump merely maintained a constant pressure at the pump, the pressure at each radiator would drop when all valves were open and each radiator would still receive a little less water than if only half were turned on. By over-compensating, the pump makes up for the increased drag on the primary circuit as velocity increases.

On the UPS2 (and I would imagine most pumps are similar), the PP1,2, and 3, differ in that the PP3 does the most overcompensation, and the PP1 does the least.
Just in case you didn't follow that, and I'm not sure I did, here is another very rough explanation of PP as explained to me by a Grundfos engineer.

Very basically, a pump could run faster and slower to maintain the same available head as rad valves are open and shut. When a valve is opened, more water can flow so the pump runs faster to maintain the same pressure. This would be a constant pressure setting.

Proportional pressure slightly over-compensates, so as the flow increases when you (or a TRV) open the flow to a rad, the pressure at the pump is not only maintained by increasing the pump rotation speed, but the pressure is actually raised a little. The reason for this is that the primary circuit (the pipe from the boiler to the motorised valve and the common return to the boiler) creates more drag when the water velocity is higher. So if the pump merely maintained a constant pressure at the pump, the pressure at each radiator would drop when all valves were open and each radiator would still receive a little less water than if only half were turned on. By over-compensating, the pump makes up for the increased drag on the primary circuit as velocity increases.

On the UPS2 (and I would imagine most pumps are similar), the PP1,2, and 3, differ in that the PP3 does the most overcompensation, and the PP1 does the least.

I would like to ask that grundfos engineer why in a 6M pump that they only allow a max 3M PP head, even the "cheap" pumps allow a 5 M PP head. I think that even the UPS3 only has a max PP setting of 3.5M.
If you take the above example that I used and assume a perfectly normal CH system. Ideally to set up the PP control, one should open up all the zone valves including HW and open all or any TRVs fully to get the maximum flow, you can then calculate the head and flow rate, I did mine by measuring the boiler deltaT and because I knew its output I was able to calculate the flow rate, I then looked at the (fixed) speed pump curve and was able to read off the head.
So if the head & flow required are 2.9M @ 15 LPM, you should then be able to set the PP control high enough to give you this but because the UPS2 can only be set to a max of 3M the head and flow will fall to 1.8M & 11.6 LPM so you are getting 77% of the max flow. IF you could increase that PP setting to 4M (3.8M to be exact) then you would have the required head & flow of 2.9M & 15 LPM on change over to PP mode. I know this is exactly how it works because I can set my Wilo pump any where between 0.5 M & 5.5 M PP head in increments of 0.1 M so if I set it to the 3.8 M above I will get that 2.9M head & 15 LPM, it will never go any higher but will ramp down as I described on reducing heat demand.
 
I would like to ask that grundfos engineer why in a 6M pump that they only allow a max 3M PP head, even the "cheap" pumps allow a 5 M PP head. I think that even the UPS3 only has a max PP setting of 3.5M.
If you take the above example that I used and assume a perfectly normal CH system. Ideally to set up the PP control, one should open up all the zone valves including HW and open all or any TRVs fully to get the maximum flow, you can then calculate the head and flow rate, I did mine by measuring the boiler deltaT and because I knew its output I was able to calculate the flow rate, I then looked at the (fixed) speed pump curve and was able to read off the head.
So if the head & flow required are 2.9M @ 15 LPM, you should then be able to set the PP control high enough to give you this but because the UPS2 can only be set to a max of 3M the head and flow will fall to 1.8M & 11.6 LPM so you are getting 77% of the max flow. IF you could increase that PP setting to 4M (3.8M to be exact) then you would have the required head & flow of 2.9M & 15 LPM on change over to PP mode. I know this is exactly how it works because I can set my Wilo pump any where between 0.5 M & 5.5 M PP head in increments of 0.1 M so if I set it to the 3.8 M above I will get that 2.9M head & 15 LPM, it will never go any higher but will ramp down as I described on reducing heat demand.

So in really simple non-technical terms:

A pump set to a Fixed Speed will apply a constant speed/pressure regardless of what’s ahead of it in the system. The result being that it could be too much pressure (particularly when a change takes place such as some rads being closed off) and it is also inefficient.

A pump set with Proportional Pressure will apply a variable speed/pressure depending on what is ahead of it (when a rad is closed/opened the pump compensates accordingly). The result being a more appropriate pressure is applied and it is more efficient.

Is that about right?
 
I have one final question on this topic:

I replaced the old Grundfoss UPS pump (because it was old) with the Grundnfos UPS2. I got the UPS2 because that seemed to be the direct replacement for the UPS.

Until John G mentioned PP I had never heard of it. What’s more, I did not even know that the UPS2 had PP.


My question is: If I had not replaced the pump I would have been left with a pump that only had Fixed Speeds. In which case, how could I have resolved the pump over problem if the slowest speed of the pump was still too much?
 
I have one final question on this topic:

I replaced the old Grundfoss UPS pump (because it was old) with the Grundnfos UPS2. I got the UPS2 because that seemed to be the direct replacement for the UPS.

Until John G mentioned PP I had never heard of it. What’s more, I did not even know that the UPS2 had PP.


My question is: If I had not replaced the pump I would have been left with a pump that only had Fixed Speeds. In which case, how could I have resolved the pump over problem if the slowest speed of the pump was still too much?
With your system like Ric2013 has shown above, cold feed before the boiler and vent after it I am a bit surprised that you wern't get some pump over "all the tine" depending on the number of rads in service. The cure: ideally I would ensure that the boiler heat exchanger has no (or partial) blockage but of course you need a RGI to do this. If you are happy not to inspect it then if you want to retain the gravity system you could shift the cold feed from before the boiler to after it adjacent to the vent but not more than 150mm away from it OR fit a fully pressurized system with a expansion vessel.

If the PP control is "curing" the problem then why worry too much?.

Are all your rads etc heating up to your satisfaction?.

I don't know if you have a boiler flow temperature indication but (if so) sometime you might watch it when the boiler shuts down and see what the temperature rise is over the next few minutes.
All this has been and is very very interesting, thanks for the feed back.
 
So in really simple non-technical terms:

In an ideal world, the pressure drop across a given radiator would always be the same. The flow through this radiator is then limited by the lockshield valve and controlled by the local TRV.

A so-called 'constant pressure' pump, which adjusts its displacement rate to achieve a fixed pressure difference across its ports, will give a constant pressure drop across the radiators provided there is no pressure drop along the connecting pipework.

In practice, there will will be a flow-dependent pressure drop due to the connecting pipework. The 'proportional pressure' behaviour of a smart pump is an attempt to cancel this out.

Constant pressure operation is definitely, in my opinion, an improvement over a traditional constant speed pump, although it makes setting up the external by-pass correctly a rather delicate operation. Whether the additional complication introduced by PP is actually worthwhile in practice I'm not so sure about; the theory is based on an assumption about the pipework that is at best a rough approximation.
 
With your system like Ric2013 has shown above, cold feed before the boiler and vent after it I am a bit surprised that you wern't get some pump over "all the tine" depending on the number of rads in service. The cure: ideally I would ensure that the boiler heat exchanger has no (or partial) blockage but of course you need a RGI to do this. If you are happy not to inspect it then if you want to retain the gravity system you could shift the cold feed from before the boiler to after it adjacent to the vent but not more than 150mm away from it OR fit a fully pressurized system with a expansion vessel.

If the PP control is "curing" the problem then why worry too much?.

Are all your rads etc heating up to your satisfaction?.

I don't know if you have a boiler flow temperature indication but (if so) sometime you might watch it when the boiler shuts down and see what the temperature rise is over the next few minutes.
All this has been and is very very interesting, thanks for the feed back.

I'm draining the system down right now to remove the X400 and flushing through. I will refill and add the X100. All rads working really well (better that they have for a long time) and HW piping hot so I'm going to stick with the PP control.
 
So in really simple non-technical terms:

A pump set to a Fixed Speed will apply a constant speed/pressure regardless of what’s ahead of it in the system. The result being that it could be too much pressure (particularly when a change takes place such as some rads being closed off) and it is also inefficient.

A pump set with Proportional Pressure will apply a variable speed/pressure depending on what is ahead of it (when a rad is closed/opened the pump compensates accordingly). The result being a more appropriate pressure is applied and it is more efficient.

Is that about right?

More or less, a fixed speed pump head falls as the flow rate increases and increases with flow rate decrease (Trv's or zone valves closing) where as PP control works in the opposite sense, as the flow rate increases the pump head increases (pump ramps up the speed) and visa versa. Most of these pumps also have CP (constant pressure) control where the head is kept constant whatever the flow rate is.
 
In an ideal world, the pressure drop across a given radiator would always be the same. The flow through this radiator is then limited by the lockshield valve and controlled by the local TRV.

A so-called 'constant pressure' pump, which adjusts its displacement rate to achieve a fixed pressure difference across its ports, will give a constant pressure drop across the radiators provided there is no pressure drop along the connecting pipework.

In practice, there will will be a flow-dependent pressure drop due to the connecting pipework. The 'proportional pressure' behaviour of a smart pump is an attempt to cancel this out.

Constant pressure operation is definitely, in my opinion, an improvement over a traditional constant speed pump, although it makes setting up the external by-pass correctly a rather delicate operation. Whether the additional complication introduced by PP is actually worthwhile in practice I'm not so sure about; the theory is based on an assumption about the pipework that is at best a rough approximation.

I picked up this description of PP control somewhere along the line and it bears out what you are saying.
I would have to say that PP control works very well for me.

PP Control
"It starts with the assumption that about half of your pressure loss in the system will be in the distribution pipe while the other half is lost in the radiators. Consequently, the pump is controlled such that it will respond to a decrease in flow with a reduction of its head and that at zero flow, when all valves are closed, it will provide half the head pressure it has at maximum flow."
 
There you go, works exactly as the spreadsheet shows.
Unfortunately the spreadsheet is difficult to understand as you don't explain where the data comes from or what each column contains.

For example:
How did you obtain the Know Head and Known Flow?
Where does the UPS2 data at the top come from? It doesn't agree with the Grundfos published data.
What does "rem 7.9 lpm" mean (apart from the obvious litres per min)?
What does series 1 and series 2 refer to?
etc etc.
 
I have one final question on this topic:

I replaced the old Grundfoss UPS pump (because it was old) with the Grundnfos UPS2. I got the UPS2 because that seemed to be the direct replacement for the UPS.

Until John G mentioned PP I had never heard of it. What’s more, I did not even know that the UPS2 had PP.


My question is: If I had not replaced the pump I would have been left with a pump that only had Fixed Speeds. In which case, how could I have resolved the pump over problem if the slowest speed of the pump was still too much?
The file will not open.

Try this link so.
The Grundfos AUTOADAPT algorithm
 
Unfortunately the spreadsheet is difficult to understand as you don't explain where the data comes from or what each column contains.

For example:
How did you obtain the Know Head and Known Flow?
Where does the UPS2 data at the top come from? It doesn't agree with the Grundfos published data.
What does "rem 7.9 lpm" mean (apart from the obvious litres per min)?
What does series 1 and series 2 refer to?
etc etc.

I would have to spend a very long time explaining the whole spreadsheet data etc but if you click in any of the cells (assuming you are familiar with s.heets) you can see every calculation carried out, however I will try and answer some/most of your queries.
The known head and known flow are from my own system, I derived it years ago by measuring the oil fired boiler deltaT, then knowing the boiler output I was able to calculate the flow rate, I then went to my pump (a salmson at that time) and just read off the fixed speed pump head at that flow. Every installation is different of course but even if you have no idea what it is, if you select PP3 on the UPS2 you may find that it will be perfectly adequate, I use a different pump (Wilo) which gives far more options and I run it at a PP head of 4M to give me what I want.

"UPS data on the top??" it comes from the PP curves in page 11 of the attached UPS2 file and I would venture that it is reasonably accurate given that I am reading it off a plain sheet.

"rem 7.9 LPM" was just some reminder to myself when building the spreadsheet.

series1 & series2 are just excel assigned labels for the two trend lines, just place the cursor above the labels and the data columns will be highlighted, the x axis (horizontal) is the pump head in meters and the Y axis (vertical) is the pump flow in LPM.
The point where the two trend lines intersect is (or should be) the actual head and flow rate achieved with a UPS2 pump on PP setting 3 based on my known values.

Should also have said that if you place the cursor in either of the trend lines and click on it that it will highlight the data for that particular trend line, if you place it in the trend line without clicking it will give you the two values at that particular point.
 

Attachments

  • Grundfos UPS2.pdf
    7.2 MB · Views: 9
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The known head and known flow are from my own system, I derived it years ago by measuring the oil fired boiler deltaT, then knowing the boiler output I was able to calculate the flow rate, I then went to my pump (a salmson at that time) and just read off the fixed speed pump head at that flow.
That just gives you the working point when that particular pump is used. That may not be the same as the required working point.

Here's a example, using my system which has a UPS2:

The required flow rate and head are 8 litres/min at 2.2m. The actual working point, shown by the yellow dot, is 9.99 lpm at 3.43m which is where the pump curve and system curve (red line) meet. See graph below.

If a PP setting is used, it needs to provide the required flow/head not those obtained by the fixed speed setting.

The attached UPS2 file is corrupted

My UPS2.PNG
 
The simple answer is efficiency. The pump efficiency peaks around the middle of the curve.
Yes, I saw Grundfos mentioning that but if that max setting of 3.0M isnt sufficiently high enough for your needs then you simply have to go over to fixed speed which is a pity really as you have lost all the benefits of PP control including much lower power demand).
 
That just gives you the working point when that particular pump is used. That may not be the same as the required working point.

Here's a example, using my system which has a UPS2:

The required flow rate and head are 8 litres/min at 2.2m. The actual working point, shown by the yellow dot, is 9.99 lpm at 3.43m which is where the pump curve and system curve (red line) meet. See graph below.

If a PP setting is used, it needs to provide the required flow/head not those obtained by the fixed speed setting.

The attached UPS2 file is corrupted,

View attachment 36462

Yes, exactly, if you need 8 LPM @ 2.2M head then the UPS2 will NOT do the job in PP mode at its max setting of 3M, it will only give 6.8 LPM @ 1.53M, just put 2.2 in cell L10 and 8 in cell M10 of my spreadsheet and just read the result off the graph. You would need a PP capability of around 3.3/3.4 to give you those required numbers.
I really couldn't recommend anyone to buy the UPS2 for this very reason. I will shortly post a modified spreadsheet using a Wilo pump on PP control to give your 8LPM @ 2.2M.
 
Unfortunately the spreadsheet is difficult to understand as you don't explain where the data comes from or what each column contains.

For example:
How did you obtain the Know Head and Known Flow?
Where does the UPS2 data at the top come from? It doesn't agree with the Grundfos published data.
What does "rem 7.9 lpm" mean (apart from the obvious litres per min)?
What does series 1 and series 2 refer to?
etc etc.
Here is a more detailed description of my spreadsheet which you may find interesting.

Most pump manufacturers PP control operate between a max and a min head where the minimum is the max/2 (see my post #234 above), for example in a pump that might have a PP set at 3M, the minimum is then 3/2 or 1.5M. Grundfos are a little different in that with the PP set at 3M then the minimum is ~ 1.2M (hard to read, page 11 of UPS file), but it doesn’t matter as the calculations method is the same for all the manufacturers and is very simple.

In the above case (UPS2.) 1.2M=0M3/h and 3M=2.15M3/h, I prefer to use LPM so 1.2M to 3M = 0 to 36 LPM. The calculation that the pump microprocessor carries out is completely proportional. So mathematically the calculated head = 1.2+(3-1.2)*LPM. For example if the LPM are 18 then the calculated head = 1.2+((3-1.2)*(18/36))= 2.1M, another example at 36 LPM the head is 1.2+((3-1.2)*(18/36))=3.0M (which we know is correct as 3M=36 LPM but just checking!) Spreadsheet: In column I (under LPM) I have started at 0 LPM and incrementally increased it in 0.1 LPM steps down through the column, (these values I copied across to column K to make it easier to build the trend.The caculation above is then done in the adjacent column J under H and gives the equivalent PP calculated head . Now the known (in this case, my own) LPM is 15 at a head of 2.9 M but as the pump starts ramping up at 1.2M (it possibly starts at 0) and because Flow is proportional to the sq.root of head then the ACTUAL flowrate at 1.2M is 15*sqroot(1.2/2.9), 9.65 LPM as shown in column L, so as the pump is ramping up this real flow rate will keep increasing and the calculated PP head will also keep increasing and when the real flow rate “catches up” with the calculated PP flow rate then the pump will stop ramping as the calculated power and the absorbed power will be equal, in this case at ~ 11.8 LPM @ 1.8M head. (the pump only looks at the power, it doesn,t measure head or flow) . Also see cells K134 & L134.
 
Yes, exactly, if you need 8 LPM @ 2.2M head then the UPS2 will NOT do the job in PP mode at its max setting of 3M, it will only give 6.8 LPM @ 1.53M, just put 2.2 in cell L10 and 8 in cell M10 of my spreadsheet and just read the result off the graph. You would need a PP capability of around 3.3/3.4 to give you those required numbers.
I really couldn't recommend anyone to buy the UPS2 for this very reason. I will shortly post a modified spreadsheet using a Wilo pump on PP control to give your 8LPM @ 2.2M.

Here you go, using a PP head of 3.3M will give you very close to your required 8 LPM @ 2M, it gives ~ 7.9 LPM @ 2.12M.
 

Attachments

  • Wilo Yonis Pico Pump Curves Extract.zip
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I really couldn't recommend anyone to buy the UPS2 for this very reason.
I have also come to the conclusion that the UPS2 PP option is a non-starter.

It is interesting that the Grundfos pump-sizing facility on their web-site never suggested the UPS2 if you specify PP operation; but it's recommended if you use fixed speed. I do wonder why they provided PP settings. The new UPS3 is much better.
 
I have also come to the conclusion that the UPS2 PP option is a non-starter.

It is interesting that the Grundfos pump-sizing facility on their web-site never suggested the UPS2 if you specify PP operation; but it's recommended if you use fixed speed. I do wonder why they provided PP settings. The new UPS3 is much better.
 
Yes, its strange alright because their old pumps were excellent long living products and some cheaper makes offer 5 or 6 PP settings, OK most of the lower ones wouldn't be used very often but the higher setting is often 4.5M or even 5M which will meet most normal sized dwelling needs.
As you say the UPS3 is better and even though it has only two PP settings, the higher one is 3.6M.
I have attached a different method of "sizing them up" which is easier to use I think than the previous Spreadsheet, I have done a few calcs using the UPS3 which are included.
 

Attachments

  • PP Calculation Alternative.zip
    10.9 KB · Views: 14
I have also come to the conclusion that the UPS2 PP option is a non-starter.

It is interesting that the Grundfos pump-sizing facility on their web-site never suggested the UPS2 if you specify PP operation; but it's recommended if you use fixed speed. I do wonder why they provided PP settings. The new UPS3 is much better.
I have a UPS2 in my own house. I got it for free because the screws were missing on the terminal box. Actually, the head it provides is more than sufficient and one of the advantages of the UPS2 for me was that the fixed speed UPS on setting 1 was far far too high, but then I have quite an old boiler with negligable head loss across the heat exchanger.

That said, I do suspect that a high head would never be required for a properly designed system: if the velocity of the water in pipes be kept reasonably low, why would you need a 6m head? That said, easier to ensure in a new system than when modifying an existing system.
 
I have a UPS2 in my own house. I got it for free because the screws were missing on the terminal box. Actually, the head it provides is more than sufficient and one of the advantages of the UPS2 for me was that the fixed speed UPS on setting 1 was far far too high, but then I have quite an old boiler with negligable head loss across the heat exchanger.

That said, I do suspect that a high head would never be required for a properly designed system: if the velocity of the water in pipes be kept reasonably low, why would you need a 6m head? That said, easier to ensure in a new system than when modifying an existing system.

I suppose we should bear in mind that the UPS2 hasn't true fixed speed curves. Even speed 1 will give a constant head of 4M from 0 to ~ 6 LPM before the head starts falling, (any real fixed speed pump head starts dropping immediately on flow demand) which with modern zoning/TRV's etc will cater for over 6 kw of heat demand at a deltaT of 15C. and with the retro fitting of condensing oil/gas boilers the trend is to get a greater deltaT of 20C to enhance the condensing effect thus leading to even lower circulation rates. So in a house with even just basic insulation could very easily be running the UPS2 pump at the ridiculously high head of 4M on "fixed speed" for significant periods of time.
I havn't any pump curves for the older UPS pumps but I would think that they would have been operating at least 1/1.5M lower head?
Having said that the 3M PP head is a bit mean to say the least and certainly will fall short in a lot of instances as on PP control the head falls with reduced flow demand so to cater for both full heating flow rates and reduced demand it would have been nice if 3.5M to 4M was available, as was pointed out above, The UPS 3 has now got a 3.6M PP head. (AND has two CP (constant pressure) settings as well!)
This one may have been replaced in a lot of cases by the UPS 2.
https://product-selection.grundfos....tid=GMA&productnumber=97549426&qcid=501056454
 
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At 6l/m the old UPS 15/50 had around a 3m head and the UPS 15/60 around 3.6m head.

The very old Selectric UPS 15/50 and Super-Selectric 15/60 has 7 and 9 foot head, at 6l/min respectively, so a little less. (I say 'has' in the present tense because I know at least one that is still running.)

All the above are on speed 1.

I suppose it would be useful to plot a little chart showing various types of pump curve all on the same axes, so comparisons could be made.

Why am I still up?
 

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  • Selectric UPS pumps old style.pdf
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  • selectric very old.pdf
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At 6l/m the old UPS 15/50 had around a 3m head and the UPS 15/60 around 3.6m head.

The very old Selectric UPS 15/50 and Super-Selectric 15/60 has 7 and 9 foot head, at 6l/min respectively, so a little less. (I say 'has' in the present tense because I know at least one that is still running.)

All the above are on speed 1.

I suppose it would be useful to plot a little chart showing various types of pump curve all on the same axes, so comparisons could be made.

Why am I still up?

Will put together one (chart) later today, I will include my own old Salmson NYL 33 which I installed in Sept 2000 set to speed 2 and was still running perfectly and quietly when I replaced it last November with a Wilo Yonos Pico 1-6 last November.
 
A bit off thread but I love this forum! It's so good to see people discussing issues using reasoned and evidenced facts supported by experience rather then slagging each other off.
 
A bit off thread but I love this forum! It's so good to see people discussing issues using reasoned and evidenced facts supported by experience rather then slagging each other off.
That's because I'm a left-leaning liberal **** as they say on Youtube when I'm trying to make a reasoned point.
 
Will put together one (chart) later today, I will include my own old Salmson NYL 33 which I installed in Sept 2000 set to speed 2 and was still running perfectly and quietly when I replaced it last November with a Wilo Yonos Pico 1-6 last November.

Here it is, I wouldn't care to be running a few of these on even fixed speed 1, especially the UPS 3 .
 

Attachments

  • Various Fixed Speed Pump Curves.zip
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I take it that's the old UPS and not the very old one, but it looks wrong. The UPS 15-50 starts at a 0 flow at 3.5m exactly, so how are you getting 3.76? Have you yet another IOM, as that differs from my data?
 
I take it that's the old UPS and not the very old one, but it looks wrong. The UPS 15-50 starts at a 0 flow at 3.5m exactly, so how are you getting 3.76? Have you yet another IOM, as that differs from my data?
You posted
I take it that's the old UPS and not the very old one, but it looks wrong. The UPS 15-50 starts at a 0 flow at 3.5m exactly, so how are you getting 3.76? Have you yet another IOM, as that differs from my data?

I got it from one of your files above... "Selectric UPS Old Style" page 1 shows speed 1 curve starting at 3.75/3.76M ?.
 
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At 6l/m the old UPS 15/50 had around a 3m head and the UPS 15/60 around 3.6m head.

The very old Selectric UPS 15/50 and Super-Selectric 15/60 has 7 and 9 foot head, at 6l/min respectively, so a little less. (I say 'has' in the present tense because I know at least one that is still running.)

All the above are on speed 1.

I suppose it would be useful to plot a little chart showing various types of pump curve all on the same axes, so comparisons could be made.

Why am I still up?

Can you post any links (charts etc) to a UPS 25-50 Selectric, power outputs 40W, 65W & 95W. (installed in a new build house in 2005/2006), still running.
Thanks.
 

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