Boiler pump running in night

[stewbie60]

Hi
I have a full evohome system work well it’s a 3 port system HW up. HW Down and Hot water. It’s a S plan + system .

My question is in the middle of the night the boiler pump makes a odd grinding noise ? It’s new .
This is the third pump in two years, what seems the happen is it gets noise making a grinding and then it blows the fuse , trips the RCD .

The pump goes open circuit, and looks as it is burnt out ?

Not sure what the issue is Evohome or circuit board , or wiring . But what is very confusing is it all works fine .

Anybody got ny ideas

Kind Regard’s Stuart

[Somebody]

I had a similar issue when the pump was running and boiler was on when no heat was called. Turned out to be the micro switch in one of the Honeywell valves.

[Richard]

Hi
I have a full evohome system work well it’s a 3 port system HW up. HW Down and Hot water. It’s a S plan + system .

My question is in the middle of the night the boiler pump makes a odd grinding noise ? It’s new .
This is the third pump in two years, what seems the happen is it gets noise making a grinding and then it blows the fuse , trips the RCD .

The pump goes open circuit, and looks as it is burnt out ?

Not sure what the issue is Evohome or circuit board , or wiring . But what is very confusing is it all works fine .

Anybody got ny ideas

Kind Regard’s Stuart

Check to see if you have an Automatic Bypass Valve fitted (https://theevohomeshop.co.uk/19-installation-materials). Sounds maybe like there isn't or its been shut?

With an S Plan or S Plan + system you should have one fitted and correctly adjusted. Lots of pumps are controlled directly by the boiler and not the zone valves, so really important an ABV is fitted to the heating circuit to allow a bypass circuit (for minimum flow rate) when the TRV's close down or the zone valves shut.