Question on shutting off water from 20+ y.o. Honeywell on demand boiler to baseboard in one zone

GrayJay

Recently moved into a new home and not too familiar with the setup of this oil boiler (see pic). It's on demand so no water heater. I have burst baseboard pipe (luckily it burst in the basement and not upstairs). I know why it burst and frankly not my concern right now (poor insulation near a basement window).

My concern is getting a temporary fix in place while I wait for daylight and call a plumber. I tried to patch up the pipe, but I really don't have the resources and my temporary patch job isn't working. Normally I'd just shut off water to the boiler, but it's in the lower single digits tonight and this would also turn off the heat to the basement causing more issues. I have a pellet stove upstairs so I don't need the heat to the area with the leak. I turned the thermostat all the way down and cranked the pellet stove up, but the boiler periodically kicks on sending water through the system. I heard gurgling as I was falling asleep, which is what alerted me to the fun.

For the time being, I turned off the valves sending water out to the first floor (zone where the leak is) from the boiler and coming back to it (there are 2 ball valves) until I can call a plumber in the morning. To be completely honest, I'm not sure which pipe sends water out to the zone and which returns it to the boiler, but I think it's the one on the left (see picture below). I'm used to zone valves with shut off valves there, but this is a different setup.

My question: Is it okay to leave configuration in place until the plumber gets here (shutting off water from the boiler to that zone), or will it cause issues to when my boiler kicks on? It already kicked on and shut off and I'm not trying to clean up water, so the valves are doing their job of preventing water from getting to the leak. I just don't know enough about the boiler to know the consequences of leaving it like this until the plumber can get here.

SuperTech

I think you need to shut off the water to the boiler if you have burst baseboards. From your picture it's kinda hard to see everything, it looks like the fill valve is behind the flue pipe. I can see the backflow preventer which is usually piped in before the fill valve. You need to shut off any valves on that pipe, that's what supplies water to the boiler.
You just have the supply and return lines for the heating loop shut off, just shut off everything if you have a pro on the way.

GrayJay

Thanks for responding SuperTech. The leak is in the loop and with the loop shut off, the leak is averted and I can keep my basement from freezing and more pipe damage. Since the temps were in the lower single digits (Fahrenheit) last night I didn't want to risk more pipes getting damaged by shutting off heat to the boiler, and to the entire basement as a result. I have a pellet stove, so I don't even need it to heat the zone it is feeding - I really lucked out. I was just wondering if I would cause any damage to the boiler if I leave it like that until the plumber can get here - or will it damage the boiler. I used to have a propane boiler with a zone valve config and a hot water tank - so not familiar with this system. I only have one floor, so no zone valves. The pipes leaving the boiler go right to the basement zone, the first floor zone and the drinking water - no HW tank.

The HVAC company is about to open so I'm going to ask them, then I'll report back

delta T

You should shut the power off to the boiler unless you have disabled that zone from being able to make the boiler fire.

GrayJay

FYI - I did speak with the HVAC guy who worked on the system before I bought the home. He played it safe and said he couldn't tell me one way or another if it was safe like that without coming down to see it. I get that he has a business to run, I really do. However, if it's not safe, I wish he would just say so.

Thanks for taking the time to respond delta T and SuperTech

delta T

I agree with him. It depends on what exactly you shut off, and what controls you have on the boiler. What you want to avoid is the boiler trying to fire and circulate that zone that you have shut off. If there is no circulation, and the relief valve is not functioning properly, you could have a serious issue. Even if the relief valve is functioning, you can damage the pump if it is trying to pump against a dead head (closed valve). If it were me, I would tell you to turn the power off to the boiler to be on the safe side of things....

GrayJay

Thanks for the clarification delta T. Good news, he should be here here within the hour.

GrayJay

I got confirmation that shutting off power to the boiler was the right move.