circulating pump setting

J-W

Hi all,

My hot water circulating pump from my oil boiler , went a bit intermittent so I changed it out for a new one (wilo YONOS ). the house is a tall two story with an attic conversion ( 2 large rads in attic). there are 19 radiators.
Typically I only have half the rads on as there only 2 of us in the house at the mo.

2 questions for ye.

1 The pump has modulating mode and constant pressure mode. Which should I use. I left it on modulating after installation.

2 What Delivery Head should I set it to. I left it on 3m after installation.

Max delivery head is 4m you can select in .1's throughout range. With the variable pressure setting should I put it higher my understanding is it if doesn't need the pressure it wont use it ?

Thanks for the help

Ciaran

shane0007

4m head is very low. Really only suitable for an apartment.
To set modulating mode, open all circuits, set into modulating mode & as circuits close, pump will modulate its speed to suit.

J-W

Thanks Shane

Really , I figured with 4 being the max if was the setting for a huge domestic house, so I set mine to 3.
I'll up it to 4m and if its not good enough i'll have to change it out again.

Thanks

John T Carroll

J-W wrote: »

Hi all,

My hot water circulating pump from my oil boiler , went a bit intermittent so I changed it out for a new one (wilo YONOS ). the house is a tall two story with an attic conversion ( 2 large rads in attic). there are 19 radiators.
Typically I only have half the rads on as there only 2 of us in the house at the mo.

2 questions for ye.

1 The pump has modulating mode and constant pressure mode. Which should I use. I left it on modulating after installation.

2 What Delivery Head should I set it to. I left it on 3m after installation.

Max delivery head is 4m you can select in .1's throughout range. With the variable pressure setting should I put it higher my understanding is it if doesn't need the pressure it wont use it ?

Thanks for the help

Ciaran

You dont say what model pump you purchased but I presume it was the "6M" one. Its obviously very important to purchase one that will give the required flowrate at the required head. With 19 rads and say a delta T of 15C across them, then you may well need a flowrate of 25 to 30 LPM if all of them are full on and you have a boiler of 26 Kw output. Looking at the Wilo Yonos pump curves, a "4M" pump will give 0 LPM at a (differential) head of 4M, 13LPM at 3M, 22LPM at 2M & 35LPM at 1M. The "6M" will give 0 LPM at 6M, 33 LPM at 3M, 46 LPM at 2M & 56 LPM at 1M. If the smaller pump has been retrofitted then it will never reach a 4M head but will still pump 22 LPM at a 2M head, obviously the "6M" pump will have no problems. 4M or even 3M would seem a very high required head, it obviously depends on the pipework diameters etc. I have a fair bit of "1/2" pipework in my 2 storey house with 13 double rads but a (measured) 1.8M differential head gives (from the Salmson NYL 33 pump curves, on speedsetting "2") a flowrate of 16.5 LPM.
These high efficiency circ pumps are very interesting and the savings are quite good even though Wilo's figures are very optimistic.

J-W

Hi John,

Thanks for all your help , it clears up a lot of my confusion.
I got back to the lad who got the pump for me , he was under the impression the one he gave was adjustable from 1m to 6m.
I told him it went to 4m max so hes getting me a 6m.

Hopefully that will fix all.

Ciaran

J-W

Hi John,

Thanks for all your help , it clears up a lot of my confusion.
I got back to the lad who got the pump for me , he was under the impression the one he gave was adjustable from 1m to 6m.
I told him it went to 4m max so hes getting me a 6m.

Hopefully that will fix all.

Ciaran

John T Carroll

J-W wrote: »

Hi John,

Thanks for all your help , it clears up a lot of my confusion.
I got back to the lad who got the pump for me , he was under the impression the one he gave was adjustable from 1m to 6m.
I told him it went to 4m max so hes getting me a 6m.

Hopefully that will fix all.

Ciaran

As a matter of interest Ciaran, Re the old pump, have you any idea of the make/model and the selected speed setting, ie 1, 2 or 3.
If your supplier is getting a pump with a max selectable setpoint of 6m then he will be supplying an 8M pump which will NOT fit between the normal 130 MM flanges. Are you running the pump now with Shane's suggestions, ie everything opened up fully and on 4M setting?. If everything is OK then reduce to, say, 3.5M setpoint, if everything still OK keep reducing the setpoint until the pump speed falls below its max, if this occurs and all your rads are hot then this pump size is quite adequate, you can then fine tune the setpoint until happy. I would think that a 6M pump should be more than adequate for your duty...John

J-W

Hi john,

Unfortunately I threw out the old pump when installing the new one , it was something like "English pump company" or something like that ,it was on speed setting 3 and was easily twice the size of the new type.

I'm still using the 4m wilo the lad who supplied it is getting me a 6m and only charging the difference.
at the moment the 4m is getting the top half of all rads warm only

John T Carroll

J-W wrote: »

Hi john,

Unfortunately I threw out the old pump when installing the new one , it was something like "English pump company" or something like that ,it was on speed setting 3 and was easily twice the size of the new type.

I'm still using the 4m wilo the lad who supplied it is getting me a 6m and only charging the difference.
at the moment the 4m is getting the top half of all rads warm only

Sorry for being a bit persistent but can you see what the actual head (meters) and power in watts that the pump is now currently running. You might also try and confirm that the pump is running at full speed. If not running at full speed then you might consider changing it over to the constant pressure mode and set it to its maximum possible setpoint (3M ??)and then see if it ramps up to full speed and note the actual head and power, again.
Thanks. John