2 pumps in series is this normal practice?

[ted35]

Hi, Thanks very much for your help and replies the problem turned out to be the pump which had been with us for 30 years approx and had failed the Baxi engineer wasn't that informed and I don't think he was familiar with the boiler it was him that advised 2 pumps when in fact there was only the external one this particular boiler does'nt have an internal one, hope this makes sense. Baxi have replaced the heat exchanger (no charge) and an independant plumber changed the pump
so now got heating.

thanks Ted

 

[45yearsagasman]

If the old pump is on the CH flow pipe, then it should have been remove and a short section of pipe used in its place. I assume the old pump has been disconnected electrically from the system? That is a simple answer, to be more precise post a pic and describe the old system in more detail.
If the pump is not used then it is laziness on behalf of your installer not to remove it.

 

[Gasguru]

Far from it, many of the problems with new boilers are down to the installer having a complete lack of knowledge regarding flowrates and head loss.

Heat exchangers found in boilers such as Worcester and Vaillant have significant resistance to flow compared with previous copper or cast iron heat exchangers.

Most installers fail to read the manuals and carry out the calculations required or understand them. An additional pump or a different setup (low loss header etc) is sometimes required.

Manufacturers are selling boilers (especially system versions) with pumps unsuitable for the boilers maximum output when coupled with some customers systems.

 

[ianmcd]

Go with 45 yearsgasman he is correct if you are just in a standard house then the pump within the boiler is all that is required

 

[Agile]

Dear OP,

We need you to tell us if the old pump is being powered?

Putting two powered pumps in series is often used to get adequate flow rate in microbore systems.

Unfortunately many boilers have a pump proving switch which does not operate with a second pump in series!

So exactly what do you have?

Tony Glazier

 

[mickyg]

depends on system...more info required.. I see alot of systems that would benefit from an additional pump due to installers fitting underated pumps or relying on the boiler pump for high resistance systems....One thing for sure its unlikely to cause a problem