Circulating Pump for central heating - which one???

Vazelothir

Hi,

looks like the pump on our old oil-fired central heating has crapped out, and I'm looking to buy a new one. (of course this would happen in january, not in june!) But, which one to buy?

The old one was a Myson (now called "circulating pumps") but no sticker or label or ID number is visible (obviously has come off, its quite old)

Anyway, I've been googling and theres plenty of makes available (e.g. Grundfos, Wilo, Myson) but I'm not sure what one to buy...

what is the difference between a 5m head and a 6m head? does it matter? its for a two-story 3 bed with 8 radiators.

Any suggestions welcomed...

cheers

Pete67

Look for one that fits between the two flanges, if you can re-use the pump fittings then you won't need to drain down the system. Most likely this means buying the same make as the original pump. Just close the two ball valves either side of the pump with a screwdriver. Turn the slot 90degrees to close so that the slot is at right angles to the pipe. Remove the old pump, clean the flanges and install new gaskets (should come with the new pump). Insert the new pump making sure that the direction of flow is correct. Tighten the nuts and open the two ball valves. Check for leaks, and vent the pump casing by opening the crew cover in the centre of the pump body.

5m or 6m head refers to the max pressure the pump will work against, either should be sufficient for your system. If you buy a three speed pump you can start at the lowest setting and increase it if there is not enough circulation to heat all the radiators adequately.

Vazelothir

that's great, thanks Pete67

btw, I assume the direction of flow will be marked on the new pump? (current pump is on the cold/return side, going in to the boiler)..

Pete67

There should be an arrow on the pump body. If not you can usually figure it out from the shape of the casting. The pump inlet (suction) goes to the centre of the impellor, and the outlet (discharge) is collected from the outside of the impellor, if that makes sense? But they are generally marked with an arrow.

PumpAnswers

Vazelothir wrote: »

Hi,

looks like the pump on our old oil-fired central heating has crapped out, and I'm looking to buy a new one. (of course this would happen in january, not in june!) But, which one to buy?

The old one was a Myson (now called "circulating pumps") but no sticker or label or ID number is visible (obviously has come off, its quite old)

Anyway, I've been googling and theres plenty of makes available (e.g. Grundfos, Wilo, Myson) but I'm not sure what one to buy...

what is the difference between a 5m head and a 6m head? does it matter? its for a two-story 3 bed with 8 radiators.

Any suggestions welcomed...

cheers

Hi Vazelothir, 90% of domestic central heating pumps are the same specification, that is 130mm port to port and either 5m or 6m more usually 6metre. 6m is 20% stronger.

Most come with 2 new rubber gaskets. A Grundfos ups 25/60 will set you back about €120. A Greenpro RS 25/6 about €60.

Personnally i'd prefer 2 cheap ones, and have a spare, because as sure as the sun rises even the fancy one will fail sometime.

Keep warm.:D

Joey the lips

:rolleyes: he is either warm or dead at this stage..... But welcome:)