Hello -
My central heating pump system is making loud rumbling noises when it runs. It's a Grundfos 18-60, which doesn't seem to be made anymore. Can anyone suggest a direct replacement that is no larger externally, as the location is quite cramped.
Is replacement just a case of switching off the power, closing the 2 isolating valves (assuming they haven't seized), and swapping the pump?
Thanks.
I think the first number (aa-bb) is the length of the pump so you're probably out of luck since all domestic pumps are now 15-xx. (You'd want a 15-60). Unless you can find extenders for the pump's [mumble]
1.25"(?) threaded connections (I think I got some from Toolstation) you'll have to modify the pipework.
I don't think that's right!
The first number is the maximum flow rate in gallons per minute (probably for historic reasons!) and the second number is the maximum head it can pump - 60 being 6 metres, etc.
The important number for physical interchangeability is the distance between flanges - often, but not always, 130mm.
The threads on the pump body are invariably 1 1/2" BSP - so the old valves should fit on the new pump without a problem.
*Providing* the valves haven't seized *and* that they turn off properly, changing the pump is fairly easy - with no need to drain the system. Always use new rubber washers.
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