We recently purchased a 1900's row house with hot water baseboard heating. The gas boiler is relatively new (home inspector said 2003 I think). It's a 2-zone system with one zone for the English basement and one for the 2 floors of the main house.

First, the thermostat in the main zone does not appear to be working. It's the standard Honeywell "round" with mercury and even when turned all the way up, the boiler doesn't fire. The thermostat in the basement does appear to be working, however there is a 30 second to 1 minute delay between turning the thermostat up and when the boiler fires (same when turning it down). Is this normal? Every other place I have ever lived, when you adjust the thermostat, the heating system responds immediately. I'll be replacing the thermostats anyway, but I'm concerned that the wiring between the thermostats and the boiler may be defective.

Secondly, when the boiler is running, it seems to shut off before the called-for temperature is reached. I'm guessing it's hitting some sort of auto-shutoff because the temperature gauge on the boiler is getting up to around 200. Is there some way to adjust this?

Finally, a quick question. There's a shut-off valve that's labeled "boiler water supply". Common sense tells me this should be open, but when we had a plumber out for another issue, he told me it should be kept closed. Which is it?

I appreciate any help. Thanks in advance,