two central heating pumps

[Inverness]

what setting should the pumps be if they are working together? O/v One on the flow is set 3 and the return pump is at speed set 2. Should the pumps not be set at the speed together?
Since it's a 3 storey house I've heard about theses loss of head pumps?someone shine light on this please.

 

[king of pipes]

Post some pictures up we may be able to advise you better its not the normal to have 2 pumps on the same circuit unless its under floor heating , low loss header or similar cheers kop

 

[townfanjon]

Guessing sombody may have installed another one to get round a problem

 

[deg]

4 pipe system with a pump for hot water?

 

[Inverness]

Maybe the reason as the pump can only pump 5 meters max when the house is height is far greater at the top?

 

[doitmyself]

Maybe the reason as the pump can only pump 5 meters max when the house is height is far greater at the top?

The height of the house is not relevant - unless it's more than 15 floors high.

 

[Best]

The height of the house is not relevant - unless it's more than 15 floors high.

It does actually matter - a system that has to pump more than 5 metres high needs a higher head pump.
Or if it has a bigger output needed or has restrictive pipes or radiators, then it also needs higher head pump, regardless of actual height of head.
The higher head pumps have more torque

 

[ShaunCorbs]

The height of the house is not relevant - unless it's more than 15 floors high.

15 x 2.4 = 36m a 6m head pump isnt going to touch that so it is important

 

[Chuck]

Maybe the reason as the pump can only pump 5 meters max when the house is height is far greater at the top?

15 x 2.4 = 36m a 6m head pump isnt going to touch that so it is important

Only relevant if the pump is for filling a tank from a well, or similar, but I doubt this is the case here.

Assuming, what is being described are pumps that circulate water around a closed loop, i.e. a conventional CH system, the vertical height doesn't matter. What matters is that the pump is correctly sized for the impedance of the circulating loop, which depends on the usual things (diameters, lengths, bends, etc.) and the impedance is low enough for a standard pump (ca 0.5 bar head) to achieve a sufficient flow rate.

Most likely reason for two pumps is one for heating and one for hot water. It's possible that someone has put two pumps in series because the circulation rate was limited by flow impedance but I wouldn't consider it to be good practice. The right solution IMO is cleaning blocked pipework or replacement of undersized section(s).

C.

 

[doitmyself]

Assuming, what is being described are pumps that circulate water around a closed loop, i.e. a conventional CH system, the vertical height doesn't matter. What matters is that the pump is correctly sized for the impedance of the circulating loop, which depends on the usual things (diameters, lengths, bends, etc.) and the impedance is low enough for a standard pump (ca 0.5 bar head) to achieve a sufficient flow rate.

I can understand the average house owner thinking that the head of a circulator relates to how high, vertically, it can pump water. But I am completely at a loss when I read trained plumbers and heating engineers saying exactly the same thing. It makes me wonder if those responsible for their training suffer the same delusion.

It might cause less confusion if the head was always expressed in bar or kilopascals; "metres head" should be consigned to the same dustbin as BTU.

The 15 floors I mentioned earlier is related to the maximum permitted static pressure of a system.