We have a separate electric hot water heater and an oil furnace that is a mono flow baseboard heater.
When we turn off the furnace the water gets Luke warm coming from the hot faucet.
The electric hot water heater is set for 130°F. When the furnace is turned back on the water then gets hot. We didn't have this problem last year but this year it just started.
I don't know what the problem is to get this fixed.

Are the two systems separately plumbed? Could be a back flow and mixing issue. Should be a check valve or backflow preventer somewhere otherwise you could have water flowing through the boiler from the hot water heater.

I'm not sure if the two systems are combined. I'll have to take a loom at the runs.

Hi Steve

It sounds like one of the elements has gone bad at the electric water heater. Do you have an electrical tester that can test for continuity or measure ohms? Let me know, OK?

Mark