Laars Mighty no hot water unless heating is on

Hi Folks,

I have a Laars Mighty boiler, it is 5 years old and ever summer I have a huge problem with it, because after I  change the mode to summer mode- so switch of the heating, the hot water stops working too. Today I give up and put back the heating mode to enable my family having hot shower. Any idea what to do, or what may be wrong. I have enough of calling the same service guys for years as I think he is not able to fix the issue permanently.


Hi Dan,

I would replace the PCB or the control panel- depending which Mighty model you have and check all the connections. From your description it looks like a problem with appliance mode control.