Hot water heating

Cindy_4

To be honest I am not sure what type of rad he put in. So yes it is possible that the rad is blocking the airflow, but I cannot say for sure. The system hasnt been set to operate permanently as yet, due to the slow recovery rate. I think what is happening is that as the hot water goes through the rad, and cooling off the tank, the water just gets cooler and cooler and therefore cannot get up to heat, and the longer the furnace runs the worse it ultimately gets. But again, am just not sure. I wanted to research this out as best I could before he comes home again so that we can make the best choice regarding this. Have any of you heard of the apollo hydro heating system? Looking forward to hearing from you all.

Cindy_4

Hot water tank used as a heating system

My husband is determined to change our gas forced air furnace in to a hot water heating system using a radiator installed over the furnace fan, and getting the hot water from our hot water tank. Even with my limited knowledge in heating systems, this does not sound like a good idea. I have already noticed that the furnace runs for hours in the mornings just trying to come up to day time temperature settings, whereas with the gas, it comes up to temp in about 15 mins. Is there anyone that can give me a list of reasons as to why this is NOT a good idea? Or am I worrying for nothing? We live in Northern Manitoba in a small 800 sqft single level home with unheated crawlspace.

Weezbo

i think it might fall in the \"uncomfortable zone\",Cindy.

Financially it is way too avant guard .

Kent_3

The concept is valid if

the water heater is quite a bit more efficient than the furnace, but most likely it is less efficient than the furnace. Besides, a radiator to retrofit your situation would be prohibitively expensive.

Cindy_4

The rad is already installed above the furnace, and was not expensive at all. The problem is that the system doesnt seem to be able to keep up with the heating demands as the furnace runs for well over 2 hours just to recover a 3 degree heat loss. Any ideas?

jp_2

cindy,

few questions:

1.) whats the size of the furnace? how old?

2.) what kind of water heater? how big?

3.) above you say the furnace runs for hours but with the gas the temperature comes up faster????don't know what you mean here?

generally heating a house with a typical hot water heater is a poor and costly idea. also, furnaces tend to larger than hotwater heaters.

ALH_4

A few possible issues

I would guess that the temperature of the water heater relative to the sizing of the fan coil has something to do with the slow recovery. If the fan coil was chosen based on its rated value at 180°F and the water heater is set at 130°F, the coil wont be warm enough to heat the house. I would set the water heater as hot as it will go.

Depending on the size of your water heater, you could be coming up against the maximum output of the water heater also. Many are rated at 30,000btu/h, but after combustion efficiency of the water heater is taken into account, the output could be as low as 20,000btu/h. Given your cold climate, this may be cutting things a little tight.

As mentioned before, the combubstion efficiency of a water heater is typically low compared to most heating appliances. However, the efficiency does vary depending on the model of water heater.

How has your utility bill changed compared to the furnace? If the gas bill is not lower, there seems to be no reason to use the hot water heating system. If the furnace needs replacement, you could replace it with a more efficient model to save fuel.

Cindy_4

The hot water tank is a 60 gallon gas heated about 2 years old. The furnace is a gas 80,000btu approx 10 years old. He put a rad above the furnace fan, and connected it to the hot water tank. So when the house calls for heat, instead of turning on the burner, the furnace fan turns on a valve which sends hot water through the rad and the fan pushes it out through the house. The problem is, at night we drop the temp in the house to around 19c, and in the morning the thermostat is to bring the house up to 24c. Well, when we were running the gas forced air, the heat came up in about 15 minutes. With using his hot water method, the furnace fan runs for over 2 hours and still really doesnt come up to temp. Hehe, I hope I explained that a little bit better.

Cindy_4

That makes sense to me. I am not comfortable with him leaving the system in while he is on the road working. He is away too long, and I am far to concerned that he'll not be home when a problem arises. The temp in the tank is turned as high as it can. My concerns are that the "efficiency" that he is concerned about will not be realized simply because hot water tanks wear out so much faster than furnaces do and in the end, the cost will equal out if not prove to be less efficient. Am I correct in assuming this?

ALH_4

Efficiency

The hot water heater could very easily be less efficient than the furnace. They may be close, but it's a fairly safe bet that the water heater is not more efficient than the furnace.

Is the furnace inoperable now? Could you easily switch it back to normal operation? That fan coil could present a significant airflow restriction depending on what it is and how clean it is.

I agree with you that it was probably better used as a standard forced air system. If it needs a new furnace, that's the way to go.

Bob Forand

RAD ???

Cindy-When you say a rad above the fan, can you explain? Is this a hot water coil ? Is it "blocking" the flow of air from the furnace ? Perhaps this is why it now takes hours instead of minutes. The CFM's used to blow into wide open ductwork, now it is being "blocked" with a rad of some sort. If the blower cannot overcome the pressure of the new rad, the system is much less efficient. How have your power bills been since the rad was added ? Make sense ?

Gerry May

I think your tank is too small and cannot produce enough BTUh that is required. You don't say weather or not you have a circulator or pump between the coil and the furnace?
Is the Radiator designed for use in HVAC system?
If so ....You gotta watch the CFM of the blower and the flow rate of the circulator....It's all gotta match