Not getting much heat

[gggGary]

crfdell a licensed wood heat inspector???
mumble mumble
I have no inspector's license but have been around wood heat "for a while".
The list is long but lets start here;
Separate oil and wood units CANNOT share a flue.
An oil furnace needs a barometric damper, and wood cannot have one.
The gross reason is a chimney fire. How do you stop one if you can't shut off the air to it?
Next up will be back drafting.
OP do you have insurance on the house?
hint; you may be paying for it but you DON'T have insurance coverage.
Call your insurance company for an inspection.
Your house, but that install needs to go.
Went looking for a combo wood oil furnace and found this;
https://benjaminheating.com/"Benjamin Heating Products has temporarily suspeneded the sales of units in the USA
Our Apoligies to all our customers "
I'll let you guess why.
I've walked the walk; My wife's house had a similar set up when I met her, removing it and installing a properly vented separate wood stove was one of the first things I did.

The dog approved.
This is some interesting reading:
https://inspectapedia.com/chimneys/Shared_Chimney_Flues_OK.php

 

[53ksm]

Since I am a licensed wood burning inspector I can say that that most building codes don’t cover wood burning systems. In Canada it is a separate licence to inspect and install wood burning systems. The system appears normally installed unless it is two separate units then there can be some issues but they would be seen on the oil side as well.

To the OP is the a combination furnace or two separate units.

It is two separate units.

 

[53ksm]

Took some temps with an temp gun from my furnace. Room temp in the basement is about 65*f I started the fire about an hour ago. Fan just kicked in. Bonnet it running 95*f flue temp 12" from out let is 550*f furnace feed door is running around 287*f. Register temp in the middle of the house is 87*f. Main house temp is 68*f and rising. In about an hour or so I'm sure I'll be cutting the furnace back. Outdoor temp is 28*f. Heating 2600 Sq ft.

Ok I bought a cheap infrared thermometer from harbor freight. I've kept a fire burning all day. It's 10° F outside. I just filled the furnace and gave it an hour. The room air upstairs is approximately 71°. My flue temp is 216°. My burn door is 339°. My bonnet is 96°. The basement is 66°.

 

[cookies]

And the world doesn’t revolve around the US how are we supposed to know where this is? This is the internet and this site has members from around the world. The pictures are also not clear that’s why I asked for more info.

Just giving advice based on my location. And after 20 years of inspecting buildings in North America the codes are not that much different.

Cheers.

https://prnt.sc/846LqZUPjYXS

 

[Mad Professor]

This is dated, but a copy of national fire code (2003).

 

[Yarz]

My flue temp is 216°

That is too cold - look at the flue thermometer in the same picture. It shows 300-500 is a good range.
If I was in your situation, I would start trying to figure out why the fire/flue isn't hot.

Can the fire breathe?

• Is the chimney clean?
• Is the chimney the proper size to get the proper draft? What chimney size is recommended by the manufacturer?
• Is the intake open/not blocked?
• Does the barometric damper on the oil furnace ruin the draft for the wood fire? (try holding it closed)
• Does the second flue kill the draft for the fire? (try blocking that flue entirely)

As mentioned above, it is usually not recommended to run wood heat flues with other appliances. I don't know why, but I can say that when I bought my house, for the deal/loan to go through, the previous owner was required to disconnect a fireplace from the chimney that serves the furnace and water heater.

 

[sean donato]

Ok I bought a cheap infrared thermometer from harbor freight. I've kept a fire burning all day. It's 10° F outside. I just filled the furnace and gave it an hour. The room air upstairs is approximately 71°. My flue temp is 216°. My burn door is 339°. My bonnet is 96°. The basement is 66°.

Like mentioned in the last post your flue temp is pretty low. I agree with his assessment and how to proceed to see if it's a draft problem. It could be like Mr P said and an airflow issue around the firebox as well. My blower is pretty low airflow so the air gets some hang time before exiting the Bonnet and going into the vents.

 

[Smitty Smithsonite]

When you're running on wood, put tin foil over that barometric damper. That'll increase the draft and prevent a runaway chimney fire if one ever got started.

 

[.358 win]

When you're running on wood, put tin foil over that barometric damper. That'll increase the draft and prevent a runaway chimney fire if one ever got started.

Combustion air vent... Some folks "seal the house".. When burning a fire inside, it has to have a good air supply.. When a good vent is in place with inch and a half or so.. you will also see less sweating in the doors and windows.. From the pressure relief... If you can run it inside to the attic, the air has a chance to warm on the way to the fire. It's helped me, just sayin.

 

[pdqdl]

If you can run it inside to the attic, the air has a chance to warm on the way to the fire. It's helped me, just sayin.

What possible advantage is there to had by warming air for combustion? It cools the house and cools off the attic with makeup air.

It's a lot more efficient to get air for combustion by drawing it from outside the building.

 

[woodfarmer]

Yarz has the best explanation.

pdqdl there was never any mention of a wood stove.

In the great white north we are required to be “WETT” certified to work on or inspect wood heat. Wood Energy Techinical Training.

A certified combination furnace always uses the same flue pipe.

It used to be that any stand alone unit could use the same chimney flue as long as oil was above wood.

Wood/Oil, Wood/Electric and wood add on furnaces have been around for over 50 years. Very simple and very dependable as long as most of what Yarz pointed out have been addressed.

 

[.358 win]

What possible advantage is there to had by warming air for combustion? It cools the house and cools off the attic with makeup air.

It's a lot more efficient to get air for combustion by drawing it from outside the building.

Is your attic vented to the outside ?

 

[.358 win]

Is your attic vented to the outside ?

My vent sticks up about 10 inches above the 12 inches of insulation in the attic.. which is vented to outside, additionally, if I fart into it, the neighbor says it sounds like the local yeti when it's horny. You can get your combust air from wherever you choose... it may or may not help your chimney draft.. it does help mine.

 

[pdqdl]

There is apparently quite the mismatch between what I thought you said and what you are meaning.

You said:

"Combustion air vent... Some folks "seal the house".. When burning a fire inside, it has to have a good air supply.. When a good vent is in place with inch and a half or so.. you will also see less sweating in the doors and windows.. From the pressure relief... If you can run it inside to the attic, the air has a chance to warm on the way to the fire. It's helped me, just sayin.​

​

Now this means that you are taking air out of your attic and feeding it to the fire, right? If I am correct, then let me clarify what I mean.

• Firstly, you are quite correct in that pulling air from the attic will improve your draft, particularly if your house is well sealed. This addresses the common problem of feeding a fire some oxygen. That fire must breath, and the air that it draws from inside a house must be replaced. Otherwise your house would develop a vacuum.
• Here is the rub: any makeup air you draw from inside the house is heated already. The "make-up" air from outside the house is cold. This is the primary reason that a common fireplace cannot hardly heat a house, because they are very inefficient with air consumption, and they send nearly all the heat from the house up the flue.
• The most efficient modern furnaces draw their make-up air from outside the house. This prevents the furnace from sucking cold air into the house.
• IF you plan on drawing your make-up air from the attic, warming it by passing the pipes through your house, all you are accomplishing is to transfer some of the heat out of your house and into the fire, and subsequently up the flue. In this fashion, your fire will draft better, but not as well as if you had drawn your makeup air from an outside source that is insulated.
• It's a long way up to the attic. Most wood-burners are centrally located in a structure on the lower floor. If accessing that attic air is easier from the attic, then that's a fine plan. If, however, your wood burner is close to the perimeter of the building, or it's a long way to the attic, then getting your makeup air from the ground floor will be more efficient and easier too.
• While most attics are indeed well vented, they are still just a bit warmer than the outdoors. Sucking your slightly warmed attic air into the fire and replacing it with slightly colder outside air, will slightly cool off your attic, and consequently the rest of the house by just a pinch. Feeding the fire with attic air is still a giant improvement over getting makeup air from within the house proper.

Does that help you understand why I suggest that drawing your makeup air from the attic isn't as good as drawing it from outside the house?

• It strikes me as a possibility to tap into the sewer vent on the home. This would be centrally located, and already on the ground floor! It's probably wildly against code, however, since it would prevent the sewer vent from working whenever the fire was not drawing air. I can see a fancy automated damper working to alleviate the problem of improper venting when the fire is out, but I doubt code anywhere would be satisfied.

Yes! My attic is well vented, both top and bottom. Getting a makeup air pipe connected to my woodburner would be quite difficult, however. And my house is so tight, I play hell getting smoke to go up the flue. While it is true that I need to get a better source for my makeup air, the easiest solution is a few changes in how my fireplace insert is installed. It's even built to be switchable from inside air to outside air. I just haven't done it yet, nor poked a hole in my fireplace to the outside.

 

[pdqdl]

...pdqdl there was never any mention of a wood stove. ...

Eh. I use wood stove and wood furnace somewhat interchangeably. I realize that isn't exactly correct, but the physics are the same, regardless of the proper nomenclature for the device under discussion.

Same for a wood burning fireplace insert. It too, is a different device, but they all do the same thing, just in slightly different ways.

I can type "stove" faster than I can type "furnace". I'm sorry to have failed by laziness to have kept up to your standard of accuracy.

 

[.358 win]

I found it "easier" to poke a stick of inch and a quarter up through some closet space other than another orifice/ penetration going outside.. The warming thing was an unplanned side affect.. Just happens to warm on the way down. Combustion air supply that does not come from around doors and windows for me is a much more efficient supply.. Had to do a few elbows and hangers to put it right under the 1600 furnace.. It even has a bug screen on it in the attic.. I immediately noticed a large difference in less condensation on the surfaces in the house.. I'm calling it a pressure vent.. that's my story n stickin with it. One thing is I have forgotten is to install the blank I use in the duct for separation of the oil furnace.. I blank it off when I leave for extended periods,, ie , only using the oil burner.. Oil is on one side,, wood furnace is 45 ft away connected only by the duct.. Two separate chimneys..

 

[.358 win]

I found it "easier" to poke a stick of inch and a quarter up through some closet space other than another orifice/ penetration going outside.. The warming thing was an unplanned side affect.. Just happens to warm on the way down. Combustion air supply that does not come from around doors and windows for me is a much more efficient supply.. Had to do a few elbows and hangers to put it right under the 1600 furnace.. It even has a bug screen on it in the attic.. I immediately noticed a large difference in less condensation on the surfaces in the house.. I'm calling it a pressure vent.. that's my story n stickin with it. One thing is I have forgotten is to install the blank I use in the duct for separation of the oil furnace.. I blank it off when I leave for extended periods,, ie , only using the oil burner.. Oil is on one side,, wood furnace is 45 ft away connected only by the duct.. Two separate chimneys..

Forgot,,,, I think it's a fairly ****** idea to use the sewer vent... Can you say "sewer gas" ?

 

[pdqdl]

I didn't say it was without potential problems. I think most folks would agree with your clever turn of phrase.

It would, however, be a viable solution for getting makeup air, if properly managed.

Every house has a sewer vent, but they aren't designed to provide makeup air. With some well engineered controls, it could work quite well.

50 years ago, most folks would have laughed at you if you suggested running two PVC pipes across the basement level of a house just to install a new gas furnace. Try to find a decent new furnace these days that doesn't include that requirement.

 

[sean donato]

I didn't say it was without potential problems. I think most folks would agree with your clever turn of phrase.

It would, however, be a viable solution for getting makeup air, if properly managed.

Every house has a sewer vent, but they aren't designed to provide makeup air. With some well engineered controls, it could work quite well.

50 years ago, most folks would have laughed at you if you suggested running two PVC pipes across the basement level of a house just to install a new gas furnace. Try to find a decent new furnace these days that doesn't include that requirement.

The few furnace installation guides I've seen recently had provisions for installing an outdoor air inlet. Houses are made a lot tighter these days. Makes perfect sense.

 

[pdqdl]

Sean, that is not really why they are installing those outdoor inlets. It is not because the houses are tight, it is because people are buying furnaces because of their efficiency ratings. Fuel is expensive, and people know that it will pay off in the end to invest in a better furnace.

You cannot get an efficient furnace without bringing in outside air. The more efficient furnaces capture so much of the heat that they condense the exhaust gases and must use PVC pipe to capture the runoff. A conventional flu would soon rust out, and the condensation would run downhill into the furnace. So long as you are putting in one pipe to capture the condensed exhaust gases, you might as well increase your furnace efficiency by bringing in outside air, too.

I do not know how they rate furnace efficiency, but it is a sure bet that sucking cold air into the building to feed the furnace is not going to be improving that efficiency rating at all. Hence, the outside air.
Higher efficiency rating = higher sales & more profit.

Back when I was young, fuel was cheap, people did not think of furnace efficiency, and the corners of the house got cold because of all the incoming cold air. In fact, the heat exchangers of furnaces were engineered so as to leave enough heat that the exhaust gases would go up the flu and not kill everyone in the building with retained carbon monoxide. My how times have changed!

The first experience I ever had with high-efficiency furnaces was when my brother (a pipefitter) installed what was called a pulse furnace. He had to install the air inlets and the air exhaust. As I recall, that was back in the middle to late '80s, and that was quite the exotic furnace to install at that time. It made too much noise, however, and fell out of favor with the purchasing public.
It sounded like a moped running in the basement!