Pump Replacement Through Modification


Failed in service on Friday 17th of July due to severe wear on the Pump Coupling, Pump Shaft and Motor Drive Shaft, both Pump Shaft & Motor Shaft were deemed irreparable.

A direct replacement pump was not available from Grundfos, as the pump was deemed obsolete. The equivalent offered was approx 300mm longer in length AND had a delivery time of 6+ weeks.


(Pic: Damaged Pump Shaft & Damaged Motor Shaft)


MSD advised that pipework modification would be very difficult and expensive due to the location of this pump.Therefore it was essential to ensure the replacement pump fitted within the existing pipework.

Second, production would be affected if this pump was not back in place by Saturday 1st August.

THE Solution

With no practical option available from Grundfos,we selected and sourced a replacement Motor from FRANKLIN, (available from stock in Germany and arranged overnight shipping). We selected and sourced a replacement Pump Section by WILO in Germany which was built in 3 Days and also shipped overnight.

Materials on the original Grundfos Pump were:

Pump: Stainless Steel: DIN W.-Nr. 1.4401 Pump: AISI 316

Impeller: Stainless Steel: DIN W.-Nr. 1.4401 Impeller: AISI 316

Motor: Stainless Steel: DIN W.-Nr. 1.4539 Motor: AISI 904

Sleeve: Stainless Steel: DIN W.-Nr. 1.4401 Sleeve: AISI 316

Rubber: E/FKM

All materials on the new pump and motor therefore had to be a minimum of Stainless Steel 1.4401 or better.

Both Pump and Motor arrived in our workshop by Wednesday 29th of July. When assembled, the replacement pump was approx. 110mm longer than the original pump. On the booster discharge, there was a pipe fitting which had some free length available. By shortening this length to the minimum, we achieved an overall length short enough to fit within the existing shroud. The only other modification we had to complete was the new Pump Section which had a DN65 Threaded Outlet. Fortunately,we were able to transfer the original DN80 Pump Outlet on to the new Pump Section.

(Pic: Original Discharge Sleeve & Modified Discharge Sleeve)

the result

Pump was collected by MSD Friday 31st July, and was commissioned successfully by MSD on Saturday 1st August.

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