Oil to Gass conversion

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Old 02-15-13, 06:18 PM
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Oil to Gass conversion

I am planning to convert my heating system from oil/steam to gas/hot water baseboard.
Iím going to install the baseboard and a heating contractor will install the rest. I have a few questions. I have heard that cast iron baseboard is supposed to be better than fin tube. I also heard there is a high output fin tube. And there is Runtal. Is that worth the money?
I am going with three zones, one for each floor. The basement and the first floor will be the first two zones. I was going to run the piping in a loop for each. The second floor is the problem. There are two bedrooms, a smaller bedroom I use as an office and a full bath. I want to run this in parallel for each bedroom. I want the bath and office looped on one zone. I donít want the bedrooms to get as hot as the rest of the house. Is there a valve that will control the temperature at the bedroom radiators (Runtal makes one for their radiators). Will this setup on the second floor work?
The first contractor I spoke with is saying one pump for the whole system. I have seen systems with a pump for each zone which is better? He is also recommending I have the chimney sleeved. Does this sound right?
Any help I can get would help make my decisions easier.
Thank You
 
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Old 02-15-13, 07:01 PM
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Hi John, the very FIRST thing you need to do is a complete ROOM BY ROOM heat loss calculation. This is the only way that you can know how much heat emitters, whether they be CI or fin-tube, or radiators, to install in each room. If you don't get this correct from the start, you could end up with rooms colder or warmer than desired.

There is a link at the top of the forum where you can download a program and do this yourself. It should take you a few hours to complete the calculation.

I have heard that cast iron baseboard is supposed to be better than fin tube
In what way?

Cast iron is somewhat slower to heat, but holds heat longer, and can result in a very even heating system.

Fin-tube heats up and cools down faster, it's a bit more 'responsive' because of that.

Cast iron can be a challenge to install properly. The individual sections use 'push nipples' to join them together. It is of course HEAVY!

Fin-tube lends itself much more readily to DIY installation and is much less costly than cast iron.

Cast Iron will require that the near boiler piping be done in such a way as to protect the boiler from cool return water entering the boiler for extended periods of time. Typically one of the varieties of BYPASS piping must be used.

Fin-tube heats quickly and doesn't normally require any special boiler protection schemes.

I also heard there is a high output fin tube
Yes, there is... Slant-Fin, for example, has many different models available. The 'Multi-Pak' series is higher output and heavier duty. The 'Fine-Line 15' is the lower output, lighter weight stuff. Fine-Line 30 is installed in millions of homes (mine included).

Here is a line of very high output baseboard that I've been wanting to try myself:

Smith Environmental Hydronic Baseboards. Heating Edge Hydronic Baseboard. Hydronic Heating Systems - Radiant Heating System, Solar Heating, Geothermal Heating

Why high output though? You would only need to use the high output if you didn't have wall space to install proper lengths, or for some other reason wanted to install less baseboard.

Remember that you need to calculate how much to install in each room and base your decisions on those numbers.

I want to run this in parallel for each bedroom. I want the bath and office looped on one zone. I donít want the bedrooms to get as hot as the rest of the house. Is there a valve that will control the temperature at the bedroom radiators (Runtal makes one for their radiators). Will this setup on the second floor work?
The valves you are talking about are called 'thermostatic radiator valves'. Google for more info, lots of manufacturers.

contractor I spoke with is saying one pump for the whole system. I have seen systems with a pump for each zone which is better?
I don't know that there's a 'better'... one pump and electric zone valves could save some electricity, but individual pumps may be a bit more reliable. Not that zone valves are unreliable, but they don't have as good a track record for long life as a typical pump does. I personally would choose one pump and zone valves... because even when they 'go bad', it's typically a ten minute, $60 repair to change out a valve powerhead. And they won't use as much electricity...

But, there are some fancy new pumps out these days that are very economical to run... problem is that they are also PRICEY, so the payback period would be fairly long.

He is also recommending I have the chimney sleeved. Does this sound right?
Yes, it absolutely does. Most gas appliance manufactures REQUIRE that an existing chimney be re-lined. MANY jurisdictions do also. I would recommend that you have the chimney lined, for SAFETY, and for proper operation of the appliance.
 
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Old 02-16-13, 09:41 AM
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Thank you for the reply.
The parallel connection on the third zone all the radiators will get enough heat?
I did a heat loss calculation using HVAC Calc. My house is 2100 sqft. including the attic and basement. The results were a heat loss of 43,896. I feel this is a little low. I triple checked the measurements and how they were entered into the program. The contractor was talking about 130,000 btu boiler.
Does this sound right?
 
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Old 02-16-13, 10:06 AM
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The parallel connection on the third zone all the radiators will get enough heat?
By 'parallel connection', I presume you mean that each set of emitters in each room will have 'home runs' back to a manifold in the boiler room?

Why wouldn't they get enough heat? As long as you can pump proper amounts of hot boiler water through them, they will output their rated BTUs.

I did a heat loss calculation using HVAC Calc. My house is 2100 sqft. including the attic and basement. The results were a heat loss of 43,896. I feel this is a little low.
I've not used HVAC Calc, so can't comment...

Why do you feel it is a little low? It may in fact be, I'm not saying it's not, but what are you basing your feelings on?

Why are you including the attic? Is it insulated and heated living space?

The simple fact is that 99% of installed boilers are at LEAST twice as big as they need to be.

Let's take as an example some 'ballpark' figures.

A home that is VERY carefully built, and insulated may have a heat loss of around 15 BTU / SQUARE FOOT. If this were your home, we're talking 31,500 BTUH.

A 'reasonably' well built home might have a heat loss of 25-30 BTU / SQ FT
2100 X 30 = 63,000 BTUH

A home with windows or walls MISSING, or VERY POOR construction might have heat loss of 40 BTU / SQ FT or MORE... there are not many homes in this condition!
2100 X 40 = 84,000 BTUH

And your contractor wants to install WHAT? 130,000 BTUH ?

Over SIXTY BTU / SQUARE FOOT ? Seriously ? Does he know what heat loss is?
 
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Old 02-16-13, 10:10 AM
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The results were a heat loss of 43,896
Knowing the TOTAL heat loss is not enough to design your system.

You MUST know the ROOM BY ROOM heat loss in order to install the proper amount of heat emitters in each room. The SlantFin program will provide you with that information.

If your contractor is unable or unwilling to do a proper heat loss analysis, RUN AWAY from him and find one that UNDERSTANDS what he is doing and has YOUR better interest in mind.

Most contractors will not spend the time to do an analysis based on speculation of getting a contract, but before they size the boiler, they MUST do it, else you will end up with a boiler that is too large.
 
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Old 02-16-13, 10:15 AM
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For some real life comparison, I installed a new boiler in my home in October.

My home is somewhat smaller than yours, around 1900 SQ FT.

SlantFin told me the heat loss was about 65,000 BTUH.

I chose the SMALLEST Burnham MPO oil fired boiler available... I think 84K input? and 74K output? (don't remember the exact rating), and even with the very cold stretch of weather we had, it was FINE.

The old boiler was 140,000 BTU...

Was I nervous about cutting the size of the installed boiler nearly in half? Yes... a little...
 
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Old 02-16-13, 11:02 AM
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Yes the program gives me a room by room heat loss. I'm going to install the baseboard myself. The attic is a finished room. But too much of a problem to run baseboard up there. I don't know what you mean by a "home run" The third zone is the second floor. I was going to run the feed and return to the second floor and tee the connections there.
 
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Old 02-16-13, 11:19 AM
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I don't know what you mean by a "home run"
"Home runs" would be separate supply and return to and from the boiler to each radiator / baseboard.

I was going to run the feed and return to the second floor and tee the connections there.
You can do that. Just make sure that the supply and return tubing/piping is large enough to support the flow required for all baseboards together.

In other words, you should not attempt to run three 3/4" baseboards from a single 3/4" pipe. You won't get enough flow... if you do get enough flow, you will hear 'velocity noise' in the piping when the system is flowing because the water in the common pipe will be moving way faster than it should be.

I've been unable to find them lately, perhaps no longer available, but there used to be THREE WAY thermostatic radiator valves that would allow you to run a 'series' loop, yet still shut off individual rads without stopping the flow through the entire loop.

The other option would be 3-way electric zone valves mounted at the baseboards.

3-way valves can be piped to 'bypass' the flow around a baseboard.
 
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Old 02-16-13, 11:30 AM
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Thank you. I have a much better understanding of what needs to be done.
 
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Old 02-18-13, 10:18 AM
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I have a few more questions. I was planning to use 3/4" pex. Is this right or should I be using 1/2"? NJ Trouper I found this valve I think Will Work.
Taco 561-5 Taco 3/4" Sweat 3-Way Zone Valve.
But the drawing shows a "T" on the inlet side and the valve on the outlet side of the radiator. Is this the correct valve?
 
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Old 02-18-13, 11:07 AM
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I was planning to use 3/4" pex. Is this right or should I be using 1/2"?
I think you'll be better off using 3/4" for flow reasons... remember that PEX is smaller than copper and the 3/4 PEX is fairly close to 1/2 copper. Go to 1/2 pex and you are looking at an equivalent copper size more like 3/8...

the drawing shows a "T" on the inlet side
What drawing are you referring to?
 
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Old 02-18-13, 11:48 AM
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I forgot it was on the spec page.
http://www.pexuniverse.com/docs/pdf/100-3.pdf
 
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Old 02-18-13, 12:13 PM
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But the drawing shows a "T" on the inlet side and the valve on the outlet side of the radiator. Is this the correct valve?
The 3-way valve connected in that fasion would allow control of individual rooms with a thermostat in each...

You will need some extra wiring... the valve of course requires a 24VAC supply, etc...

It's too bad we can't seem to find the 3-way thermostatic non-electric valves any longer.
 
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Old 02-18-13, 02:41 PM
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I used HVAC Calc for my house and came up with about 49,000 BTU/hr with a 10F design temp. One night when it reached 10F outside, I measured the amount of gas consumed until morning to get an actual measure of the heat loss of my home. I calculated about 37,000 BTU/hr heat loss. Manual J programs do seem to estimate about 20%-30% more than actual. I would say your results are right in line. I have no idea where your contractor got his number from. He may have based it off of the size of the current boiler or the output of your radiators.
 
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