Head loss calculation

1874

Is there a good online resource to calculate head loss to see if a pump in the system is of sufficient size, the furthest rads upstairs from the heating system dont heat up well or at the same rate as other rads, Im not sure if the pump can pump to the distance, the furthest rad valves are stuck so cant adjust, I'm not sure if its also because the piping feeding the rads are a type of qualpex (but looks cheaper) from the main copper pipe (22mm I think) at the back of the house where everything feeds off and returns to a parallel copper return pipe.

The pump is in the boiler house, I recal that it looked newly replaced, but I did not look at an information on it, looked like a standard sized domestic heating pump, but its a long run from the boiler across the entire house to the hotpress where all the central heating feeds up and back across the house to the upstairs, so double the length of the house for the supply alone (just for the upstairs), the downstairs is the same although they dont seem to have an issue. (basically pipes run across the house and back 3 times each for upstairs and also downstairs. I think the head loss will be written on the pump and while it doesnt seem to have to fight too much gravity to get upstairs, the back and forth must add resistance to flow?? not to mention going down the 15mm plastic pipes that feed the rads

John.G

Can you post a close up photo of the pump label or its exact model etc.

1874

https://www.boards.ie/discussion/comment/121484106#Comment_121484106

Ill have to look tomorrow, its outside, I'm sure it is a redish (I think grundfoss)

1874

I checked, The pump is a boiler-M8, reddish colour, looks like 3 power/speed settings with H(m) head in metres values at 3,5,6. I couldn't make out the setting it was on as the picture I took was too blurry, but a quick check online shows it must be set at position 3, ie 6 meters of Head.

John.G

If this is the pump below then ensure its on the highest fixed speed setting III or maybe CP2 but NOT any PP setting, and NOT Auto.

Also post the power its running at w.

https://spares-direct.com/products/boiler-m8-6m-circulating-pump-a-rated

1874

https://www.boards.ie/discussion/comment/121487443#Comment_121487443

The pump is not an automatic speed/flow? altering pump, no digital display, its a purely mechanical switch to go between I,II, III. It appears (99% certain) it is on 3 based on a pdf downloaded. The pump was replaced 2 years ago according to a date written on it.

Really what I'm looking to do is see if I can do a calculation preferably from an online resource, input the pipe lengths and see what the head loss is for the existing pipework. I don't think there is a point getting a replacement automatic energy efficient pump possibly of the same head loss value if I may need a bigger/more powerful pump, likewise I dont want to put a bigger pump in there if it isn't needed and there is some other problem. The pump is marked as replaced in 2021, It looks very clean condition. It's a boiler-M8 25/6G-130, looks to be set at the max no. 3 position which is 93 Watts.

John.G

Can you post that pdf. but any standard 6M pump set to max should easily service say 10 rads even if set to speed2 ~ 4m head, you say the downstairs is OK, if you shut these off and if the u/stairs don't heat then its not a pump problem IMO, if you have a sealed system ensure the pressure is not < 1.0bar.