Maintenance on low activity boiler

vaylie

Sorry for the bad phrasing - but I currently have an oil fueled steam boiler with a heating coil for hot water. And I'm considering installing mini splits for cooling in the summer and heating for the warmer temperatures + heat pump water heater. It will be a dual fuel system.

However, I'm not sure how it will affect my steam boiler if it sees much less use than before. If I get both the mini splits and the heat pump water heater, then it's conceivable I'd only be using the boiler for a few weeks / month a year.

Does it have a negative effect on the boiler? I'll still do annual maintenance as usual but I'm wondering if this use case requires something more. Would I have less to worry about if I kept the tankless coil for hot water?

Thanks all in advance for your help!

EdTheHeaterMan

Water chemistry inside the boiler should be kept a little on the alkiline side. @ethicalpaul can give you advise in that. as far as the oil burner side, you will be using less fuel and perhaps the fuel have a full tank now, you may still have some of that oil in 2 or 3 years form now. yopu will want to treat that oil with some chemicals to keep it fresh for next year. A full tank is better than a half of a tank as far as condensation forming inside the tank. the water will find it's way to the bottom and that is where oil eating bacteria will grow and make that black sludge you often see in oil filters. Hot 4 in 1 is my go to additive.

Other than that I see no reason you can't keep using that boiler for only a few weeks a year.

ethicalpaul

Getting rid of the tankless coil is something I'm a huge fan of (not that that's worth much LOL). It just seems silly to me to heat up a massive 500 pound boiler to then heat a few gallons of water after a shower, then let all that heat slowly escape into the basement (I'm thinking of the 3 reduced-heating seasons of course—in the winter it's not a big deal).

I put in a heat pump water heater 4 years ago and it has been amazing.

In my opinion, every steam boiler owner should be adding some boiler treatment to boost the pH to around 10. It greatly reduces corrosion. Here's a video I made about it!

Drain as little water as possible, just leave the water in there during the off season.

I'm convinced that firing the boiler increases corrosion a lot, that's why we always see boilers rotted out at the top, way above the waterline. Normally you'd expect corrosion to be the highest at the interface between water, air and iron, but that doesn't seem to be the case in steam boilers.