Coal Boiler to NG Boiler? Some questions

Cyclist77

FIrst time here. But have been following for a decade!

So I retrofitted our home with radiant floor heat with a coal stoker boiler. I did all the work myself and had a bit of assistance moving the boiler into place.It has worked extremely well even with the "work " involved to maintain it. But as I get older and the $ of coal has gone up significantly I am considering a change.

I have been reading about combi units but the complexity of the unit and $ and long-term use has me abit concerned. So I am leaning toward a CI chimney vented unit. Maybe Burnham or Weil-McClain. My coal boiler is rated at 85,000btu. What NG size unit would you suggest for a replacement?

So my question to you fellows is. Is it reasonable for me to plumb in a unit and then have a tech do the start up?

Thanks for your response!

Tom

bburd

Have you looked into installing a gas conversion burner in your existing boiler? If only six years old it's probably in good shape.

Cyclist77

I installed the boiler in 2010. Funny you mentioned the idea of a conversion as I had that idea last night!

I don't think I want to go that route.

It would be a "cleaner" setup with a "real" NG boiler.

EdTheHeaterMan

A gas conversion burner on boilers that are designed to burn oil makes sense because the oil boiler is designed to use a flame in the combustion chamber and the new gas flame is located in the same place.

A gas conversion burner in a hand fired boiler has always been and will always be a less than ideal design. Since the 1940s the idea of putting a oil or gas burner in a hand fired boiler has yielded a less efficient heating system when compared to a boiler that is designed for a oil burner or a gas burner from the initial drawing board design.

That said, If there is room for both appliances in the boiler room, adding a CI boiler with a couple of isolation valves might be a good idea. The lower priced boilers will be at the 80% efficiency end, while those with power assisted venting will get closer to 85% efficiency. Personally, I would go for the less complicated models and sacrifice 2 to 3% efficiency. The savings on less maintenance and repair will offset the slightly higher gas bill. That is just me.

If I could get a standing pilot without a vent damper boiler, I would go for that. With a millivolt gas valve, you could get gravity heat when the electric goes out. Those were the days!

As far as what size you should get? That depends on how much heat your building requires on a design temperature day. (what you need on the coldest day of the year). You need a load calculation (Heat Loss Calc) to determine that. If you get a 85,000 BTU system and you only need 45,000 BTU then you are going to waste $$ on the bigger boiler and waste $$ on the operating cost. You want to get close to the correct size.

But as did happen in the 1940s when older coal customers kept their homes at 80° to 85°F with the coal, when the oil burner with a thermostat was set at 70°, there were many complaints from customers. Setting the thermostat at 70° was what the instructions said. but the home felt too cold and the customers that were afraid of that new fangled flame in the basement were afraid to set the thermostat at 80° in fear of blowing up the house.

When you banked the fire on your boiler for the overnight, did the temperature get warmer before it got cooler? And that cold room in the morning reminded you to stoke up those flames in the boiler every morning.

The automatic heat may take a little getting used to.

leonz

You have a keystoker kaa-2 coal stoker with a 100 pound coal hopper that can burn rice or buckwheat Anthracite coal.

Your three bed coal stoker fire grate is identical to the one I have in my kaa-4-1. The kaa-2 was not designed a dual fuel coal stoker boiler. You could remove the entire stoker and hopper and sell them and install a gas burner in a replacement mounting plate making sure you use high temperature gasket sealer. You would need to weld the ash pit closed with new plate steel.

You could leave the hanging baffle and flue breech baffle in place to hold more heat in too. You would have to install a very small gas burner and use the honeywell triple aquastat controls and leave the L6006L in place.

EBEBRATT-Ed

@Cyclist77

Peerless and Weil McLain are solid and there are others, but I am not partial to Burnham.

Cyclist77

Thanks for the replies you fellows are sending!

Ed,I just spoke to a retired plumber who lives close by. He heated with coal using a forced air furnace and switched to a Peerless NG boiler. I took a look at them and they are quite a bit more $ than other boilers.

So this winter will be my research time!

So as a former finish carpenter/ woodworker that installed the coal boiler and radiant system. Do you see a problem with me having a go at aNG boiler and then getting a tech todo the start up?

Thanks!

Cyclist77

Would youguys like to see a few pics?

leonz

Your insurer may very well have issues with it if it is not inspected. You would save much more money installing a hot water storage tank like the fully insulated rectangular New Horizons 490 gallon hot water storage tank to use with your kaa-2. You have to keep in mind that thermal mass is money in the heat bank and the more thermal mass you have the more heat you have available to heat your home.

new horizons 490 gallon storage tank 0000244_300.jpg