i installed a grundfos 15/50 circulator pump at a friends house as a favour. everything seemed fine but when it came to calling for the heating to turn off it wouldn't. i used the wire from the old grundfos pump and just wired it up like for like so i cannot see why this would happen. anyone have any ideas?
New pump installed but heating will not turn off
- Thread starter sleevey
- Start date
Make and model of boiler
maybe it was like that before you arrived, especially if someone has been tinkering with it. Fitting a new pump on the old cable would not cause it.
look for any motorised valves and count how many cores come out of them, and where they go, There may be a wiring centre where all the cables come together. If you can post some photos of the programmer, valves and pump, and the cables between them, it will help.
Youy can get wiring diagrams for boilers and their controls, some are not very simple, but we need to know the layout of the system you are working with, so don't pick one at random.
Or it might be that the boiler has an overrun timer on it to keep the pump running for a while after the boiler stops firing (this is to prevcent overheating). Mine runs on for 12 minutes.
look for any motorised valves and count how many cores come out of them, and where they go, There may be a wiring centre where all the cables come together. If you can post some photos of the programmer, valves and pump, and the cables between them, it will help.
Youy can get wiring diagrams for boilers and their controls, some are not very simple, but we need to know the layout of the system you are working with, so don't pick one at random.
Or it might be that the boiler has an overrun timer on it to keep the pump running for a while after the boiler stops firing (this is to prevcent overheating). Mine runs on for 12 minutes.
i didnt even open the wiring centre as i didnt want to mess anything up so just disconnected the cable from pump and replaced. it was a grundfos as well so i guessed it wouldn't be a problem. brown wire to L. blue to N, yellow/green to earth. nothing is ever that simle itr seems. 
i did notice that the 3 port valve had some crusty residuel on the compression fitting on inlet to valve as if there had been a leak at some point. could that have been the problem all along? only some of the radiators would get hot while the ones downstair would only be luke warm?
did you bleed the system and pump and make sure any iso valves are open 
yes i did vent the pump and the isolation valve were open as the radiators were working fine. the problem is that the heating will now not turn off! customer has gone from being too cold to being too hot! what a mare!!
i read the post wrong.
if its constantly on i would look for a motorized valve being stuck open.
did you manually slide 1 open when refilling?
if its constantly on i would look for a motorized valve being stuck open.
did you manually slide 1 open when refilling?
what kind of checks can i do to see if it is a problem with the motorised valve? the room thermostat/programmer does not turn the heating off when called. customer did state that there was an issue with a bad connection with the wiring centre and u sometimes have to (his words) jiggle the wire from fused spur switch to get the system working.
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