Grundfos UPS3 Pump Modes

[IanGMT]

Just had a Grundfos UPS3 installed, replacing old UPS.
Working well, but I wish to understand a little bit more about the Proportional Pressure (PP) mode

If I run it in Constant Curve (or Speed) mode, CH & HW are fine, pump running.

If I go to PP mode CH & HW outputs are still fine.
BUT, the pump does not seem to be running. no noise or vibration to touch!
AND, the setting lights are in flashing mode, not steady.

Very intrigued to know what is going on.

System
Traditional open vented with HW tank and 3 port valve. Pump is external to boiler (not combi) 99% sure it is 2 pipe.
5 small rads in small terrace house
Thanks
Ian

 

[SJB060685]

@John.g take it away my friend

 

[ShaunCorbs]

pp will adjust the pump speed to the resistance of the system

the flashing is to identify the pp mode constant is constant pressure

sealed or open vent system ?

 

[IanGMT]

Shaun, thanks for the info on the flashing
System is:
Traditional open vented with HW tank and 3 port valve. Pump is external to boiler (not combi) 99% sure it is 2 pipe.
5 small rads in small terrace house.
So I suppose I am asking if this set up is suitable for PP mode
Ian

 

[ShaunCorbs]

I would stick it on cp 2 you could use pp but as there’s not much change to the system eg trvs opening and shutting it’s not entirely worth it

 

[SJB060685]

@ShaunCorbs a modulating pump on a non modulating boiler a good idea? My thinking is no, lower flow rates increases chance of boiler overheating.

 

[John.g]

Its a non combi but non modulating?. A open vented system especially with only 5 rads could IMO easily result in air being drawn into or pump over the vent with a fairly powerful pump like the UPS3, if its the model I think it is then PP2 should give the required performance with less chance of the above.

 

[ShaunCorbs]

@ShaunCorbs a modulating pump on a non modulating boiler a good idea? My thinking is no, lower flow rates increases chance of boiler overheating.

that’s why I suggested constant pressure also it’s not a big circuit around 5 rads
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Its a non combi but non modulating?. A open vented system especially with only 5 rads could IMO easily result in air being drawn into or pump over the vent with a fairly powerful pump like the UPS3, if its the model I think it is then PP2 should give the required performance with less chance of the above.

heat only boiler I’m thinking

 

[John.g]

Just had a Grundfos UPS3 installed, replacing old UPS.
Working well, but I wish to understand a little bit more about the Proportional Pressure (PP) mode

If I run it in Constant Curve (or Speed) mode, CH & HW are fine, pump running.

If I go to PP mode CH & HW outputs are still fine.
BUT, the pump does not seem to be running. no noise or vibration to touch!
AND, the setting lights are in flashing mode, not steady.

Very intrigued to know what is going on.

System
Traditional open vented with HW tank and 3 port valve. Pump is external to boiler (not combi) 99% sure it is 2 pipe.
5 small rads in small terrace house
Thanks
Ian

Ian, if you are very interested/intrigued in the above I can give you (as I see it) a good idea of what the different modes will do in your case if you answer a few questions.
Is this the installed UPS 3 model.?
Is it a gas/oil fired boiler and approx output.?
Is the 3 port valve a mid position valve that gives you CH and HW on together if required.?
Do the radiators have thermostatic radiator valves (TRVs) fitted. ?

 

[IanGMT]

John
Yes your UPS3 doc is the model. It is the current Grundfos model which replaces the old UPS and the recent UPS2.
Sold as one model for most domestic situations.
Gas fired (old Suprima 60), looking at manual could be 18.6 or 22 kW
Yes, 3 port mid-valve (new Drayton MA1/679-3)
Only 2 rads with TRVs (both upstairs)

Many thanks for your interest and time
Ian

 

[Ric2013]

Looking at the pump curves, it does seem a better design than previous Grundfos pumps, with greater overlap of varying control modes (constant pressure, proportional pressure, constant speed).

Proportional pressure is designed for use with radiators and TRVs, so might be the best setting, but...

...this doesn't mean you should necessarily use PP modes, as you need to consider whether the low pressure PP provides will ensure radiators and boiler have enough flow. Any more than that is usually just extra noise (plus TRVs will not work properly if high pressures mean they are forced to run in almost closed conditions the majority of the time). Sometimes the easiest way is to consider the temperature drops across the boiler, the radiators, and hot water cylinder coil as these are easier to measure than the flow itself.

I have had to use the 'wrong' curve when attempting to tweak a badly-designed system into getting sufficient flow through radiators, and some old systems relied on higher pressures because speed 1 on an old UPS gave so much pressure at low flow rates that the system was designed around the (oversized) pump and won't run happily on PP.

If you are using an automatic bypass valve or there is one in the boiler, you need to go for a constant-speed setting (as on the old 3-speed UPS models) in order for it to work, but if there is a radiator permanently on that can't be turned off, this would be your bypass and doesn't need a fixed-speed pump.

Looking at the respective pump curves page ?20 (had to source manual elsewhere as link provided not working for me). Below 1.4m3h (0.4l/s or 23l/m) the proportional pressure modes will give the lowest pressures, and the pump should be quietest and using least energy in these modes. The simple answer to your question is that this may be why you can't hear the pump running, but if the water is circulating and the boiler is happy, all may very well be in order.

 

[John.g]

Assuming that Ian's system requires a head of 3.5M for a flow rate of 20 LPM then PP2 will give a actual flow rate of 17.4 LPM at 2.65M, if the system only requires a 2M head for 20 LPM then the actual flow rate will be 24 LPM at 2.95M, so PP2 is probably a reasonable setting. PP1 should give 11.7 LPM at 1.2M or 16.1 LPM at 1.3M for the above conditions. Of course CP1 may be a reasonable setting as well, the main thing is to check the header tank especially if on CH only and any TRVs have throttled in, there are numerous posts on here where changing to PP mode has "cured" air ingress/pump over problems with open vented systems.

Unfortunately for reasons that are beyond me, there are no true constant curve (CC) A rated pumps like the old traditional circ pump where the head started falling with increasing flow which made it relatively easy to set up a ABV, the UPS3 gives, in, effect. 5 constant pressure (CP) modes and 2 proportional pressure (PP) modes.
Constant Curve (CC) 1 maintains a head of 4.2M between 0 & 12.5 LPM, CC2 5.1M between 0 & 18.7 LPM and CC3 6.4M between 0 & 29 LPM. CP1 maintains 3.0M between 0 & 47 LPM and CP2 4.5M between 0 & 32 LPM.
PP1 gives a flow rate of 0 to 58 LPM between 1M & 2M, PP2 0 to 41 LPM between 1.8M & 3.7M.

 

[IanGMT]

John & Ric,
Many thanks for all the information and data, and advice on how to think about the system.
Problems come in 3s +, in my case new pump, then 3-way valve and today fixed the leaky float valve in the header tank. On Ist install, at CC2, I was getting warm water in the header tank + overflow! In a sense, a good problem to have :~)

So, as CC and PP are both possibilities, I will take a very pragmatic approach.
In the evenings, I will set a mode at a particular speed and over a few evenings see which mode/speed combination suits the idiosyncrasies of this system.
But, when the weather gets cooler, it is 14 C at the moment here in SE London!
Again, many thanks for your time
Ian

 

[doitmyself]

If I run it in Constant Curve (or Speed) mode, CH & HW are fine, pump running.

If I go to PP mode CH & HW outputs are still fine. BUT, the pump does not seem to be running. no noise or vibration to touch!

That's becasue the pump does not need to run at such a high speed (3, by any chance?) to circulate the water round the system. Below is the UPS3 set of graphs with a sample system curve superimposed. (Each system has a unique curve which shows how the head varies with flow.) Ideally the pump should be providing just enough head at the rquired flow.

The blue circle marks the desired working point; the red circle shows what happens if you set the pump to fixed speed 3; and the green circle shows the operating poimt if PP2 is selected. The actualoperating point is always at the junction of the system curve and the selected pump curves. PP1 is not suitable as it would mean a lower flow rate and consequently a higher temperature differential. (The working point is for a 23kW boiler at 20C differential - approx 1 m³/hr.)

 

[John.g]

John & Ric,
Many thanks for all the information and data, and advice on how to think about the system.
Problems come in 3s +, in my case new pump, then 3-way valve and today fixed the leaky float valve in the header tank. On Ist install, at CC2, I was getting warm water in the header tank + overflow! In a sense, a good problem to have :~)

So, as CC and PP are both possibilities, I will take a very pragmatic approach.
In the evenings, I will set a mode at a particular speed and over a few evenings see which mode/speed combination suits the idiosyncrasies of this system.
But, when the weather gets cooler, it is 14 C at the moment here in SE London!
Again, many thanks for your time
Ian

I'm not surprised really at the problem with the header tank at a CC2 setting which is a 5.1M pump between 0 and almost 19 LPM. You said in one post that the "setting lights are in flashing mode" and "the pump does not seem to be running" quoted, above. I don't think those lights should actually be flashing as the selected mode LED should be illuminated and a combination of green & yellow LEDs ie, CC2 should be green followed immediately by one yellow, PP2 would be green, yellow, space, then another yellow.

It would help immensely if you can supply some idea of the UPS 2 pump fitted or even the age, roughly, as doitmyself I'd say will identify the pump curves and if we can assume that it was running in one of the only available? CC modes without any problems then should be able to match the UPS 3 to it. In the meantime I would run in PP2 or CP1 which is a constant 3.0M.

Is the boiler non modulating??.

If you could measure the pump power with a smart meter then we can deduce the head and flow immediately.

 

[IanGMT]

John G
Thanks again for your input.
The LEDs are steady on CC mode (I have used 1 & 2 speeds, not 3).
The LEDs are flashing on PP mode (both speeds), and a silent pump

Old Pump (possible age 30 yrs!)
Grundfos Selectric 15-50

New Pump
Grundfos UPS3 15-50/65 130

Photos attached

The Boiler is vintage too (so assume non-modulating?)
Potterton Suprima 60 (got the manual for more spec info)

If relative heights significant:
Boiler is downstairs in kitchen
Pump, 3-way valve & HW tank upstairs in airing cupboard
Thanks
Ian

 

[John.g]

Yes, the flashing LEDs seem OK.
That's a veteran selectric alright, it was manufactured in week 10 of 1997.
I don't have pump curves for it but as its a 5M pump then I would keep a eye on the header tank and see what is the highest setting you can achieve without any movement when running on CH only, I think PP2 might be your best bet for achieving this without a excessive temperature rise through the boiler, PP1 as stated elsewhere is probably too weak. CP1 also worth considering (after PP2).
Anyway hopefully you have enough info to get the optimum setting for your system.
You might let us know what the final settings are.
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@Ric2013 posted a photo of your pump in Jan 2019 in another thread but cannot open it.
If you still have that old selectric you can see its speed setting.

Can you see the layout of the vent & cold feed where they T in to the system in the hot press, I have a +40 year old open vented 20kw oil fired boiler with the circ pump positioned on the boiler return and a "combined vent&cold feed" in the attic which makes it virtually impossible to get pump over/air ingress with. The more normal conventional system would have the pump on the boiler flow then the vent and then the cold feed with the vent&cold feed no more than 150mm apart, this also works well I think. Have a look at yours and work backwards from the diverter valve so you might have diverter valve, pump, cold feed, then vent, this assumes the pump is on the flow pipework. If your system is very dirty then you may have a blockage somewhere but if the system refilled without any problems then probably not.
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Back for more punishment, have found screenshot of curves very close to your old pump I think, based on this then speed 2 would have given 15 LPM at 2m which will result in a 19c rise in a 20kw boiler, so if your system circulates to these numbers then PP2 will flow 17 LPM at 2.6M and even PP1 will flow 12 LPM at 1.25M.

 

[Ric2013]

You said in one post that the "setting lights are in flashing mode" and "the pump does not seem to be running" quoted, above. I don't think those lights should actually be flashing as the selected mode LED should be illuminated and a combination of green & yellow LEDs ie, CC2 should be green followed immediately by one yellow, PP2 would be green, yellow, space, then another yellow.

IIRC the UPS2 does not have flashing lights, but a quick look at the diagram on p14 of the UPS3 IOM would suggest the lights should be flashing, although this is not made explicit in the accompanying text. [EDIT: come to think of it, I think my UFH in the UK has a UPS 3 and I think it did used to flash in PP mode (although obviously my UFH was not set to PP).]
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Back for more punishment, have found screenshot of curves very close to your old pump I think, based on this then speed 2 would have given 15 LPM at 2m which will result in a 19c rise in a 20kw boiler, so if your system circulates to these numbers then PP2 will flow 17 LPM at 2.6M and even PP1 will flow 12 LPM at 1.25M.

Afraid not, John. Your pump curves are for a UPS25-50. Very different from the UPS 15-50 which has, to quote myself (quote edited):

"At 6l/m the old UPS 15/50 had around a 3m head.

The very old Selectric UPS 15/50 has 7 foot head, at 6l/min.

All the above are on speed 1."

Afraid the files I have for the old UPS are saved on my laptop in the UK and I can't get the uploaded ones to open either.

 

[John.g]

Have you any curves for the pump in question?.

 

[Ric2013]

Have you any curves for the pump in question?.

I'm abroad. I have nothing useful on me except a couple of spanners a retired plumber friend has kindly given me so I can at least do some DIY. All my manuals and tools are back at home.

I'm assuming the OP has this model: https://www.anchorpumps.com/mwdownloads/download/link/id/2978/ The pump curves are on page 20.

 

[John.g]

It was the old selectric curves I was looking for, hadn't seen or read your comment re your laptop, there must be some way of downloading attachments from old posts.

 

[Ric2013]

It was the old selectric curves I was looking for, hadn't seen or read your comment re your laptop, there must be some way of downloading attachments from old posts.

Be alright if they'd open at all. Forum glitch?

I'm also doubting my own comment about a 3m head at 6l/m on speed 1. I've found a UPS 15-50 manual online, but it isn't the correct one as not 40/70/105W. I'm also doubting that my version was the correct version.

Quite why Grundfos has to give the same model number to so many versions of the pump is a bit beyond me!

 

[John.g]

One could write a small book on the problems appearing in open vented systems just because the circ pump is changed, if I was in the trade I would make very sure to note the pump model and setting before replacing it.

 

[Ric2013]

One could write a small book on the problems appearing in open vented systems just because the circ pump is changed, if I was in the trade I would make very sure to note the pump model and setting before replacing it.

Well, I suppose if the system is designed correctly, issues such as pumping over should not happen, even if the new pump head is wrong.

What you'd realise if you were in the trade is, however:

A. The old pump setting was probably already wrong. People fiddle with things even if the original installer left the setting correct.

B. Systems often aren't designed properly.

C. Quite possibly the system was never properly balanced by the original installer.

However, agree that it is very good practice to note the previous setting before changing the pump. It gives you a starting point at least!

 

[doitmyself]

I'm also doubting my own comment about a 3m head at 6l/m on speed 1. I've found a UPS 15-50 manual online, but it isn't the correct one as not 40/70/105W. I'm also doubting that my version was the correct version.

I noticed the difference between the pic of the 15/50 and the pump curves, both posted by the OP. The wattages may be different but the amps are the same. Then I noticed that the curves say 230V but the pump says 240V, which would account for the higher wattages on the pump. So I reckon the curves do refer to the pump in the pic..

I think it was around the end of the '90s when the UK and Europe decided to 'harmonise' the mains voltages - one used 220V and the other 240V. A change to 230V for everyone and a change of tolerances and, hey presto, the UK manufactured goods met the European Standard, and the European manufactured good met the UK standard. In reality, nothing had changed.