Replace furnace - cracked heat exchanger


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Old 11-05-08, 09:38 AM
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Replace furnace - cracked heat exchanger

Hi folks. I am 1,000 miles from home and the wife just called to tell me our 13-yr old oil furnace has a cracked heat exchanger. I had her call for service because the blower was cycling off and on while the oil burner was still firing. I had a clogged nozzle recently and assume the same thing was happening. My oil company recommends a Williamson TMP-105 replacement, says they have installed dozens of these with no problems. I have a couple of questions that I'd like to get some independent feedback on. I live in Connecticut and the old furnace was 130K BTU for a 2,400 sq ft house. Does 105K sound adequate, even with a more modern unit? Also, the Williamson only has an 80.2 AFUE and is not available with a variable-speed blower. Should I consider upgrading to a Thermo-Pride, or one of the other Williamson furnaces? Dealer says this model is easy to find, which would let me schedule the replacement within a couple of days. Anyone care to share opinions?
 
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Old 11-05-08, 10:39 AM
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Originally Posted by mbct451
I live in Connecticut and the old furnace was 130K BTU for a 2,400 sq ft house. Does 105K sound adequate, even with a more modern unit?
Maybe, maybe not. The only way to know for sure is to do a load calc (aka Manual J). If they didn't do that it is time to ask, and maybe have someone else do it to be sure its correct. It is very common for over-sized equipment to be recommended.

VS blowers can lower your electric bill some, add comfort, but I recall reading they may perform worse if your duct work isn't matched.

Is oil your only option? I don't know the fuel costs in your area, but NG or even propane may be cheaper. Going dual fuel by adding a heat pump to your setup will likely help you save.
 
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Old 11-05-08, 10:51 AM
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NG is not an option, despite the high-pressure transmission line only 1/2 mile away. LP could work, but time is an issue when the current furnace is not operable. Its 62 degrees in CT right now, but was in the 30's just last week. I'm handicapped by being way out of town for all this and don't want to have the wife making decisions on LP tank placement, etc. As far as the BTU's, I am trying to get at least one more bid in, and a new contractor would have to do his own calculations. But again, the wife works, I am out of town and its tough doing all this long-distance.
 
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Old 11-05-08, 11:30 AM
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Thermo-Pride will be there for the long hall. 3 times better than anything on the market.
 
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Old 11-05-08, 12:15 PM
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I understand why you might want to go with oil due to time, but I would have to agree with Mbct, You might be suprised how quick they can get an Lp tank out there. An elderly friend of ours has an oil burner and Oh Boy, He spends Alot on oil. We have a bigger place (albeit slightly better insulated house) and we have all electric resistance heat and our heating bill is a 3rd of what his is, and thats including other electric use. You could always get a space heater to tide you over a few days until they get a new unit in.
 
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Old 11-05-08, 12:25 PM
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Thanks for the response, Civicminded, but I think you are agreeing with dac. I'm the one looking for current info on furnaces. The economics of fuel are very dependant on where you live. I am in CT, where we have some of the highest electric rates in the country UNLESS you live in one of the little towns that built their own generating plant. I am not in one of those towns, so electric is cost-prohibitive around here. LP is almost as bad because of a very limited distribution system and small customer base. My dad uses LP at his farm in WV where there is a lot of LP usage and he pays about 2/3 of what I get quoted up here. From what I can tell, oil is #1, followed by NG if you are in a place that has gas pipelines at the street, followed by LP and electric. Or wood/pellets, etc. A surprising number of fairly upscale homes are putting in small stoves of one type or another as auxiliary heat in remodeled or expanded space.
 
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Old 11-05-08, 12:28 PM
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Originally Posted by Civicminded
I understand why you might want to go with oil due to time, but I would have to agree with Mbct, You might be suprised how quick they can get an Lp tank out there. An elderly friend of ours has an oil burner and Oh Boy, He spends Alot on oil. We have a bigger place (albeit slightly better insulated house) and we have all electric resistance heat and our heating bill is a 3rd of what his is, and thats including other electric use. You could always get a space heater to tide you over a few days until they get a new unit in.
Yes, my thoughts as well. I suspect you will find an ample supply of gas furnaces (just have to pay a little for the propane kit). I'll bet the Propane company will agree to move the tank later if you agree to pay for the extra copper needed. If they don't, just threaten to switch suppliers.
 
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Old 11-05-08, 04:13 PM
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All true, but yet another consideration is that I also have an oil-fired HW tank. So that would have to be switched out as well. I think I am sticking with oil, both for economy and net out-of-pocket today. I got one recommendation for Thermo-Pride vs. Williamson, but that switch also adds about $2K to the materials cost. I don't think I will be in this house long enough to get the payback on that one. Also the unit the oil guys are quoting is a CHB105, not the THB105 I indicated in the original post. Looks like a better-quality furnace with a larger blower motor and the ability to swap out for a variable-speed motor if I want to in the future.
 
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Old 11-07-08, 06:24 PM
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You are correct. It does depend on your location when it comes to fuel choice. Stick with oil and I would strongly consider the Thermopride.
 
 

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