How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Phil Your Own Question
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8769
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

I have the exact same question as the other guy. I just

Customer Question

Customer: Hi, my name is***** have the exact same question as the other guy . I just bought a house with a duomatic olson wood/coal furnace and I have been having troubles with firing it. It has a very poor draft system even though I just cleaned the stove pipes and the chimney I get smoke backdraft and creosote buildup quickly. I was hoping to find a manual to see if there was something special about firing this furnace. Any ideas?
JA: Thanks. Can you give me any more details about your issue?
Customer: When I build a fire, I leave the draft open, but the only way the fire will burn is I have to open the feed door to let air in. once the fire gets roaring I can close the feed door and try to control it with the draft. Sometimes it works sometimes not. I have wood that has seasoned for two years, so I know that it is dry. I was hoping to find a manual for this furnace to see if there is some thing special about the way it should be fired.
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to HVAC Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: yes
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.


do you have a combustion air pipe bringing outdoor air into the furnace area/room?

Customer: replied 1 year ago.
No, it just draws air from the basement.
Expert:  BillyHvac replied 1 year ago.

the unit sucks air from the basement for the combustion...the house, if well insulated and tight, goes under a negative pressure. Even on new homes now it is code to have a 6" intake pipe from outside to equalize the pressure.

Try an experiment and open a window near the unit and see if it runs better

You may have to add a fresh air pipe for combustion air.

Customer: replied 1 year ago.
This house was built in the 1940's and is far from airtight. There are plenty of drafts coming into the basement to supply fresh air. Adding another 6" pipe for fresh air from the outdoors seems redundant.
Expert:  BillyHvac replied 1 year ago.

This not an electronic fiasco...mechanical is basic draft.

What comes into play?

Cold stack (exterior chimney)

supply air and demand air...nothing magical.

If it seems redundant then to you then try something else...but it is a very simply want draft to get up and out...if you truly believe you enough leakage to feed that burner (which I doubt), unless you are seeing daylight through cracks..then you will have to look at why stack is so cold...

But that in itself can be helped with a forced draft. Or you can use a Tjerlund exhaust fan made for this...but it hinders efficiency.

I will opt out and see if someone can deliver information more to your liking.

Expert:  Phil replied 1 year ago.


We can do some tests on this.

If its negative pressure problem, opening a window 3 inches will solve the problem and the heater will draft properly.

Try that, if nothing changes then its the problem is with the draft opening in the stove, perhaps it is blocked or you have fire brick or some other obstruction in the way... we need to examine the stove for those possibilities, Your mention that sometimes you can run the stove with the door closed and sometimes not points in that direction.

So lets look at that first.

Next we can examine the flue pipe and chimney etc. I will need photo's for that.

Customer: replied 1 year ago.
I think I found the problem with the stove. I noticed that after I shook the grates and emptied the ash pan there were still quite a few ashes in the bottom of the stove. I got a small ash shovel and a good light and reached in and cleaned out the rest of the ashes and found that they had placed another piece of grate on top of the shaker grates which was preventing the ashes from being emptied out the bottom when I shook the stove grates. I removed the extra piece and cleaned out all the fine fly ash and then started a fire and it had a good draw and everything seemed to be working the way it should be. I thought about still using your idea of leaving a window open 3 inches, but the temperature outside is 12 degrees and it was getting a good draft without the window open. I am going to try it this way for a while and see how it works, if it seems to be ok then problem solved. If not I will try the window open, but I will get back in touch with you because there must be something else you have in mind because keeping the window open in the weather we are going to be getting will not be a good thing. Our temperatures are going to be hitting single digits and below zero very soon, so I guess I wonder what your other thought was.Bob Semo
Expert:  Phil replied 1 year ago.

Good work Bob, leaving the window open 3" was a test only, if that had reversed the problem we would know that you needed a supply air duct to the stove.