Help with an old home heating

firedrill157

Background - I live in west central Georgia (near Columbus) in a home that was completed in 1860. The home has no insulation. When I purchased the home in 1985, I contacted every HVAC contractor in the area. I should point out that where I live is old plantation country and is extremely rural. Not a single contractor was willing to install a hydronic system. I grew up in New England where and when all houses used radiators. I love hydronic heat and hate hot air heat - so I built a system on my own. I won't bore you with the details - it is very amateurish, but it works. The problem is that the system is fired by an outdoor wood boiler. It is getting more difficult to find the wood, and more importantly, it is more difficult for me to lift and load the wood. I am now a ranking senior.
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So, is there a propane boiler that may work? I had (still have) a propane boiler that acted as an emergency or when we were away backup for the wood boiler. It is a Dunkirk Plymouth with an 81% efficiency and a stated 170,000 btu capacity. The boiler hot water tank is very small compared to the wood boiler - just a few gallons compared to 105 gallons for the wood boiler. The gas boiler (while only used a few times) ran virtually all the time and hence was expensive. The best propane price is about $2 a gallon.

The home is a Greek Revival 2 stories with about 1600 square feet on each level. The downstairs has under floor hydronic piping (ineficient but pleasant) with a large heat exchanger in the hall. The upstairs level ahas a heat exchanger in the hall and a 3 foot baseboard heater in 4 bathrooms.

The detached kitchen - about 400SF - has under floor heating.

I've tried to simplify the setup. I am not trying to get a real upgrade for the system. Given my age, 5 or 10 years would be a be a good run. If I could simply plug in a suitable propane boiler that was fairly reasonable in cost (and cost to operate), I would consider this a home run.

Any contractors in my area? Anyone with some solid advice?

Jamie Hall

How is the system controlled at present? What pumps and valves do you have? And how is it piped? Is the propane boiler in parallel with the wood boiler?

I expect that something can be figured out to work; a first though off the top of my head would be to use a propane boiler to heat the water in the wood boiler. Another possibility would be to install a properly sized md/con with outdoor reset, but the controls and piping and valving for that would be more complex.

nicholas bonham-carter

Maybe the present propane boiler could be made to work "fairly well", but we would need pictures and some more details.
By heat exchanger, are you referring to a radiator?--NBC

firedrill157

A large Taco circulator pump circulates water constantly. The water is pumped from the boiler (100 feet away from the home) to a manifold where water is sent through the various loops. The loops are "controlled" by valves although it is not possible (by me) to know what the flow rates are. Since the floors are thick, the home is seldom warm. As a matter of fact, most people would find the home too cool.

The "heat exchangers" are just that. They were purchased from an industrial supply company. 3/4 inch lines run to the heat exchangers; 1/2 inch for all under floor loops. The water line from the boiler to the home (manifold) is 1 inch. A fan is mounted behind the heat exchangers and the fan is thermostatically controlled.

The propane boiler is simply a back up. Throwing a few valves shuts off one boiler and places the other on line. While the gas boiler is 10 years old, it has not run more than 85 hours. It simply ran all the time. I suspect the water reservoir is simply too small.

I do not attempt to perfect the system. I simply am approaching the point of being unable to man the wood boiler. If a gas boiler would be somewhat economical, the adoption of the boiler system would free me from being the boiler caretaker and provide heat - even when we were gone from the home. We have no one who can man the wood boiler when we are away.
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Thanks for responding to my initial request. I hope to hear more.

nicholas bonham-carter

Keep a record of the supply and return temperatures while operating the gas boiler, and probably some analysis can be done from that.
The water content of the boiler may not be a factor, if the piping is right. Does it short-cycle, instead of running constantly on the coldest day of the year?
Compare the piping specified in the boiler installation instructions with what you have, and see if improvement can be made. Is it piped primary/secondary? What size circulating pumps are on the system?
Could your heat exchangers be air bound, restricting their output?
There are some excellent books in the shop here on hydronic heating principles, and improvements.--NBC

RobG

Can you post some pictures of what is existing, both the boiler and the radiant? The more the better.