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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8769
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Have an old Armstrong furnace model number 101A-35-105. How

Customer Question

have an old Armstrong furnace model number 101A-35-105. How can I get a copy of the parts manual?
JA: Did you check the furnace's filters?
Customer: It appears to have a missing gas orifice and owner controls flame by throttling input gas pipe valve
JA: Do you plan on doing the work yourself?
Customer: yes
JA: Anything else we should know to help you best?
Customer: no
Submitted: 1 month ago.
Category: HVAC
Expert:  Phil replied 1 month ago.

Hello, is this a furnace as part of a central AC system or some other type of heater, please describe,

We can go from there



Important note about RATING my work:

I am a retired mechanical engineer and HVAC/electrical/ refrigeration and boiler contractor ... with 56 years in this business. The last 20 of those years consulting for major firms nationally..


All I ask is please respect me and my input by selecting the***RATING LINK***at the top of your page, that is the only way I am credited through the site. Rating does not affect your charges nor ability to refund if not satisfied.


If you need to be coached through a full diagnosis/repair,and wiring etc. for up to two days, and wish to be trained to use test instruments...... that goes well beyond' Just a simple Answer' of course, and goes beyond what most other experts here offer.....rate my answer so far positively.. . and I will deliver that training and coaching to you All on the same dime so to speak.


Lacking a positive rating I can spend days helping a person at my own expense and loose my shirt, shorts and socks on the deal.


Attach a close up photo of the wiring diagram glued to the inside of the blower access door and I will mark it up with trouble shooting instructions then follow up with step by step training and coaching until you have a solution.


Photo must be exceedingly well focused. Use the 'add files' link next to your send button to get the photo to me.


Phone call offers:

If you wish to accept the companies $25 phone call offer, if indeed they send you one, this will go a *lot faster, but it IS 100% optional... or we can continue here in this dialog box at no additional charge.

Customer: replied 1 month ago.
it is a central forced air furnace in a private home
Customer: replied 1 month ago.
it has only one large burner
Customer: replied 1 month ago.
are you still on line?
Expert:  Phil replied 1 month ago.

Thanks, ***** ***** model numbers beging with an A or if not, have at least two letters in them.

That number you gave looks like it might be a serial number.

The model number is ***** a tag inside the same compartment as the gas valve in most cases.


On this end I must come and go to do research type up responses etc, I can't stand by... so there can be a wait sometimes

Customer: replied 1 month ago.
I got the number from the data tag inside the furnace and it was in the box labeled "model number" and it was an aluminum tag and the number stamped into it. my first thoughts were that it was a conversion from an oil fired furnace so maybe the model number is ***** an oil fired furnace or the conversion kit.
Expert:  Phil replied 1 month ago.

Thanks, ***** ***** numbers are hand stamped... the model numbers are normally printed, see if that might be the case.


If you can send me a few photo's, including a close up and exceedingly well focused photo of wiring diagram glued inside blower access door, and some photo's of the front of the furnace with the doors removed I can be more helpful.

Use the 'add files' link next to your send button to attach the photos

Customer: replied 1 month ago.
I can do that but not today. how do I get back to you and where do I email the photos?
Expert:  Phil replied 1 month ago.

You do not email the photo's, load them into your computers 'my pictures' file, then use the 'add files' link at the bottom of your reply page next to the send buttion... follow the prompts.

Customer: replied 1 month ago.
Had a tough time getting photos into my computer. There are three that turned but but I can't get them transferred. I was using drop and drag.
Expert:  Phil replied 1 month ago.

Use the 'add files' link next to your send button and follow those particular prompts

Customer: replied 1 month ago.
There are no prompts from the +add files link.
Customer: replied 1 month ago.
some how they just came. can you open and view?
Customer: replied 1 month ago.
I must go of line a this time. Will you be in tomorrow?
Expert:  Phil replied 1 month ago.

Hello, thanks for the photo's. That furnace was built in the 1960's if not earlier, it is beyond viable repair... the heat exchanger in such a furnace has a 90% chance of leaking carbon monoxide into the living space.

You can buy a new furnace of that capacity also 80% efficient for under $750... and with installation under $3500 if you shop around in most areas.

Tell me which direction you are from the center of the nearest larger town or city, and I will locate a well rated outfit or two that can quote you a new furnace installation.


Customer: replied 1 month ago.
I requested, and will only pay for a parts manual, not an appraisal of the furnaces future. We know the risk of the heat exchanger leaking, from the start so this is not anything new. It is running very poorly and producing a lot of soot. Getting the burner operating efficient will reduce the chance of it producing a lot of carbon monoxide. You have the data plate information so can't you contact Armstrong?
Expert:  Phil replied 1 month ago.

Hello again, that is fine, payment is optional.

the furnace is way over 50 years old, no parts are available from the manufacturer, distributor or dealers... .. an old timer in the business, generally working alone however would be able to tune it up for you and jury rig or make a workable part.... those types, like myself however are either dead or retired as a rule. Finding one would be a challenge. You might also get a hash job type who would turn your furnace into a life and safety hazard.

Whats left are larger companies with sky high liability insurance premiums and who have no interest in working on something that old... unfortunately. Their insurance will not cover jury rig repairs.


Good luck with it.