Salamander pump

[coopersim]

i have two salamander pumps supplying hot water under pressure to two different bathrooms and also a kitchen.

when the hot water taps are turned on only slightly the pump "hunts" kicks in for a few seconds, stops, then starts again, stops (carries on like this for 5 loops) then cuts out all together and a manual reset of the pump is required - which is a real pain as they are in the loft

the installer has been back many times, the manufacturer has been involved and changed the pump electronics, and still no joy

can anyone shed any light on this?

for info, the system is a vented hot water cylinders (2 of) 2 condensing combi boilers running in tandom in the loft (baxi) where the cold water tanks are located

thanks

 

[gas4you]

Are you sure the boilers are combis? what hot taps do they supply if 2 h/W cyls are supplying kitchen & bathrooms?