Grundfos ups2

[Jt77]

Hi I've replaced the pump with a ups2 and it's much quieter, however it still won't shut off lije the old one.

Central heating and hot water controls are both off and thermostat is turned down but pump is still running and boiler if firing up. Even when I switched off the boiler directly the pump still runs.

I think the issue is the 2 way central heating valve (there are 2 honeywell). Likely to be the microswitches stuck.

Would you agree and is there anyway to shut the pump off without shutting the ring main its hard wired to? Thanks

 

[endecotp]

is there anyway to shut the pump off without shutting the ring main its hard wired to?

All the central heating valves, thermostats, pumps etc. and the boiler itself should normally be isolated by a single switch somewhere, probably an FCU or sometimes an actual plug in a socket.

 

[stem]

It depends what is controlling the pump. Sometimes it is controlled by the boiler so that it can continue to run for a short time after the boiler goes off to allow it to dissipate some residual heat. However when you say

Even when I switched off the boiler directly the pump still runs.

By that, if you mean that you turned the boiler thermostat or boiler mounted switch to 'off' it doesn't really prove anything because the boiler could still be running the pump. To know for sure it would be necessary to isolate the electrical supplies to the boiler. If the pump still runs then, then the boiler will not be operating it, and the pump will be being controlled by the microswitches in the motorised valves, and in which case as you suspect;

I think the issue is the 2 way central heating valve (there are 2 honeywell). Likely to be the microswitches stuck.

Looks more likely. However, if that were the case, the boiler would be 'on' also, and not just the pump.

If you have '2-Port' Honeywell valves which is what I believe you are describing, have a multimeter and know how to use it safely, it's quite easy to test the microswitches. If with everything isolated, you were to disconnect the grey and orange wires from each of the motorised valves in turn from the control wiring, these are the wires to the microswitch, they should be open circuit. If they are aren't, then you have found your problem.

It does seem a coincidence that this happens just as you change the pump though. It would be difficult to wire a pump up wrongly unless you have changed the cable to it at the wiring centre end. Have any fuses blown at any point? If so, and a short circuit has been created at some point, it's quite likely that the contacts in one of the motorised valves have been welded together. But the test will reveal this.