Old(ish) Grundfos proportional pressure control circulator

[Coddey]

I'm trying to set up a Honeywell DU145 ABV with an ALPHA 15-60 130 (Model number 59526443) and work out the speed setting. The pump has one variable dial (no C1/2/3 ect).

Grundfos support have no info on the pump as its from circa 2001, so unable to help. Its running 5 rads in a small 2 bed flat with only one TRV turned down (the rest fully open).


Any advice would be welcome

 

[ShaunCorbs]

Try c1 and see how it goes if all heats up leave it there if not up it to c2

 

[Coddey]

Try c1 and see how it goes if all heats up leave it there if not up it to c2

There is no c1, c2 ect. Just one variable control

 

[ShaunCorbs]

Split the viable speed into 3 and set to 1st 3rd

 

[Coddey]

Split the viable speed into 3 and set to 1st 3rd

???

 

[ShaunCorbs]

Are you trying to set the bypass? Or the pump ?

 

[Coddey]

Are you trying to set the bypass? Or the pump ?

Both ideally.

The pump is currently set on the max setting, and the ABV on number 2. However, the previous owner admitted to playing around with it. So I though it best to start from the beginning. I dont know why the ABV is there has the loo rad has no TRV, just 2 open lock valves unless the ABV is for the hot water?? Its an S Plan system.

 

[ShaunCorbs]

S plan system?

Try turning the pump down to half and see if it heats up

 

[Coddey]

S plan system?

Try turning the pump down to half and see if it heats up

S plan: two separate valves. one for heating and the other for water.

I've tried that a week ago, and it was slightly better than full on. The rads warm up more equally on half. I imagine the next step would be to slow it down another 1/4 or keep where it is?

 

[ShaunCorbs]

Exactly keep notching it down until something stops and notch it up one

 

[Coddey]

Exactly keep notching it down until something stops and notch it up one

Excellent.

Any tips for the ABV setup, or turn the bleeding thing off lol I did have the pump curves that I could have used with the boiler flow to set the ABV, but its difficult with a variable control with no markings to find where the curve is.

 

[John.g]

S plan: two separate valves. one for heating and the other for water.

I've tried that a week ago, and it was slightly better than full on. The rads warm up more equally on half. I imagine the next step would be to slow it down another 1/4 or keep where it is?

I doubt if the pump, with just one control is a proportional pressure (PP) controlled pump, its more than likely a variable speed pump where each pump head is determined by the speed setting, as the pump flow increases the head falls just like the old 3 speed pumps or it may be, even if unlikely, a constant pressure (PP) pump where the pump head remaind constant as the flow increases. Its hard to imagine it giving less head/flow at full setting than say at 1/2 setting, its more than likely a 5M or 6M pump at full speed so a ABV setting of 0.2, 2m, at full speed would/should have resulted in massive bypassing, so do as suggested in post # 10, then maybe shut all rads except the loo rad and open the ABV until it just gets warm the reclose it 1/4 turn or so. Or as you say if loo rad is always on maybe just shut it fully?

 

[Coddey]

The following is the only info I have on the pump:

Grundfos ALPHA 15 60 130 (Model number 59526443) Integrated proportional pressure control
GRUNDFOS ALPHA pumps feature automatic control of differential pressure through adjustment of pump performance to actual heat requirement without the need for connection of external components.

With the heating or hot water on, there is always somewhere for the water to be pumped, the issue on S Plan is when both the two port valves shut and the pump overrun is on. Without the ABV open there is no where for the heated water to go.

I'm not sure of the boilers minimum flow as they wont tell me and its not in the manual, so unsure of the pump speed /ABV relationship using the flow / curve charts. Therefore, If I set the pump speed to low, will it cause issues with the boiler. Also, will a lower speed in a PPC pump result in low pressure preventing the ABV to open.

To be honest, the debates I've read about the relationship between 'S Plan / ABV / Modulating Pumps' is on par with my PhD thesis !!!!

 

[John.g]

If the pump is proportional pressure control only then a ABV will only work in the following way.
If you have set your pump (like mine) to a 4.6m PP setting, this means that the pump will circulate ~ 20LPM (1.2m3/hr) at 4.6m and 0 LPM at 2.3M, in other words when you shut off all zone vales then the pump pressure falls to 2.3M.
So you run your boiler to the loo rad only , and slowly open the ABV to just start passing water (maybe then shut it in a touch), when the zone valve closes then the pump head will be 2.3M or very slightly higher at say a required flow of 6.5LPM, 390 LPH) through the ABV at a ~ setting index of 0.23, you open either your HW or CH zone valves and the pump head can rise up to 4M (mine rises to 3.5M with 10 rads), so ay 3.5M, the ABV will now pass ~ 10.8LPM, 650LPH, so useless, in this (PP) case you can just install a gate valve or throttling orifice to give you that 6.5LPM (which should be quite adequate for any boiler on overrun) it will the rise to a max of 8.0LPM at 3.5M which may be acceptable at the expense of a higher boiler return and a bit of efficiency loss.
The above obviously is by passing at all times.
You can do your own interpolating below, mine might be a bit out.

 

[John.g]

You could install this normally open 2 port valve as a bypass wired in parallel with the two zone valves which will close when either of the zone valves is signalled to open?.

Honeywell Home V4043B1257 22mm Normally Open 2 Port Motorised Zone Valve​