I recently bought a house with a somewhat quirky heating/ hot water setup that the last owner put in and configured himself. It's and oil fired slant fin intrepid boiler with a tankless domestic coil. Also connected is a wood fired boiler/ stove that we are not using at the moment, we are relying on the oil fired part only.
The part that's making problems now is the hot water system. It worked fine for the first week or so that we were in the house, now it ceased to produce hot water on demand. To get hot water, I have to turn up the thermostat to create space heat demand, then I will also get hot water. Just turning on the hot water faucet does not make the boiler turn on.
I checked the Honeywell aquastat, and as far as i can tell the settings are ok, HI is set to 190, LO to 160 and DIFF to 25. The LO setting definitely has no effect, if I turn down the thermostat in the living room and there consequently is no heat demand for space heating the boiler cools off to way below the LO setting, I had it cool down as low as 90F. Turning on the hot water faucet doesn't turn on the Boiler either. Only turning up the living room thermostat will.
Anything else I can check myself before calling an HVAC guy?