Monster furnace DIY or find a Pro?

[pitogo]

Hi all,

New home owner look for information. I purchased a house built in 1953. The furnace is also from that era. The home inspector did put in the report the furnace should be replaced but our lawyer said if it ain't broke don't fix it but he did ask the seller to have the unit serviced which they did by having the ducts cleaned.

1. I live in West Orange, NJ
2. House is Center Hall Colonial with around 2400sq/ft. Construction is wood panel siding, wood board exterior, 2x4 wood beams, insulation and plaster wire mesh.
3. The furnace is an American Standard/Radiator Standard from the 1950's the only marking on it I can find is Sunbeam. Its around 5' W x 3.5' D and 5' H.
4. Gas/forced hot air
5. n/a
6. single zone
7. Filtrete 3M-50

Things I've done so far, I changed the thermostat to a new programable one replacing the junky round mechanical thermostat. The system has two wire bundles, R and W for heat and Y, G, Rc for cooling. And I've also taped all the gaps where there were holes in the duct work for the add-on A/C/

I have two simple goals the easy one is:
I am trying to find an owners manual for this thing. I want to figure out where I change the air filter, or does the air handler not have a filter slot? It also looks like the a/c is an add on with its own air handler.

The hard goal is to eventual replace both with a single cabinet one quarter the size of this one.

Top view


Side view - and yes in the top right corner of the pit is a 5' ladder


Overall view

[Grady]

I wouldn't touch that thing with a 10 foot pole other than to rip it out by the roots but, to answrer your question about the air filter:
It is probably supposed to go in the compartment below the vent pipe. I'm presuming that's where the blower is.

If this system was installed in the 50s, the ducts were probably not sized for A/C. If you want it done right, BE PREPARED for major expense.

[airman.1994]

Duct cleaning has nothing to do with servicing the unit! They are total different things. He should have had the HVAC system cleaned just not the duct

[lawrosa]

Wow... See the saddle valve on the gas line?

Why is it built installed in a hole? I wonder if thats a mini bomb shelter for it for if it ever explodes.....

I am really wondering what the string is for going through the small hole in the duct work. I would not pull it, might be the detonator!!!!

But anyway it might have brakes. That metal oval thing hanging off the side looks like a brake fluid resovoir from a 68' olds cutlass I once owned. Hmm ...

All jokes aside though and I am sorry I could not resist but, I am with grady. The old saying, "once you touch it you own it."

I really would not do too much with it and at all costs get a CO detector asap if you dont have one already. You dont want to wake up dead.

Mike NJ

[SeattlePioneer]

No, that's not a saddle on the gas piping. It's a tap off the shutoff valve for gas for the pilot burner, including a valve to shut off the pilot burner gas supply.

Common enough on old equipment.

I agree that cleaning the ducts is not servicing the furnace, and having it carefully checked on old equipment like that is VERY worthwhile.

The thing hanging off the side was probably once a reservoir for a humidifier that was decommissioned at some time.

I would suppose that the air filter is or ought to be behind a door in the the same end of the furnace as the vent pipe, with the air flow going into the furnace on the side where the vent pipe is and the warm air plenum on the right side where the air would flow through where the humidifier was and then up and out on the right side of the furnace. You can see where the fan limit switch is located ---- the return air ductwork would be to the left of that, on the left side of the furnace.

My reservation about servicing the furnace would be getting access to do proper inspection and maintenance, not the age of the furnace. It would probably be no fun. When it's no fun, it may not get done, which makes a good inspection all the more important, since maintenance and inspection may have been neglected for years.

[Muggle]

Replace that pos before it poisons you with co or burns the house down.

It should have been changed 30+ years ago.

[SeattlePioneer]

Have it inspected. If the heat exchangers are OK you just need to do whatever maintenance may be needed and it will be fine.

There is no need to replace a furnace just because it's "old." Replace a furnace if it's unsafe for some actual reason.

It might also be worthwhile to replace the furnace due to it's releatively low efficiency. It's 70-75% efficient compared with 90% plud efficient furnaces available today. But that would be your call.

[Muggle]

You can't tell if a heat exchanger is bad just by looking at it without complete dis-assembly.

Once startup and shutdown losses are taken into consideration, the efficiency could be as low as 55%.

A 50 year old pos could lack the safeties even found on a 20 year old unit - vent safety switch and rollout switch.

Keep anything more than 30 years old running is absolutely absurd. Had it been replaced 20 years ago, the savings could have payed for a new furnace several times by now.

[SeattlePioneer]

Well Muggle --- I guess every furnace should be replaced whenever it's seen by a repairman. That's certainly the philosophy used by a regrettable number of heating contractor who send "repairman" out to sell new equipment to people who may not need it.


Pretty much every furnace is engineered to extract as much heat as possible and still insure that the combustion gasses will rise through the vent and wont condense into water. 70-75% efficiency is a reasonable ballpark level to suppose in my view.

Again, it's quite common for those who aim to sell people new equipment to exaggerate efficiency levels to minimum they can possibly justify.

You are certainly entitled to state your opinions. Personally, I think they are too negative.

If the owner wants to replace the equipment, I wouldn't argue with that. If he wants to continue to use it, I'd have no objection to that if it's inspected and found to be safe and has any needed maintenance work done.

[Muggle]

70-75% efficiency is a reasonable ballpark level to suppose in my view.

Clarification for the thread starter:

Natural draft furnaces vent air continuously up the chimney, reducing seasonal efficiency by 5-10%.

Take another 3-5% off for the pilot.

Take another 5-10% off for having a very thick heat exchanger which takes 2-5 minutes warm up (while an enormous amount of heat pours up the chimney) before the fan even comes on. (at the end of the cycle some of the residual heat stays in the house, most of it escapes up the stack)

So, even though the steady state efficiency could be at high as 80%, the seasonal efficiency is always well below that.

With modern equipment, the fan is on within 30 seconds, there's no standing pilot, and the exhaust is vented by a fan which shuts down when the call for heat ends.

Why is it built installed in a hole? I wonder if thats a mini bomb shelter for it for if it ever explodes.....

That feature might come in handy.

[pitogo]

Our first fuel bill was $201, 55 for electricity and 145 for gas. October was a bit warmer than normal so I think Jan/Feb/Mar when its bitter cold we'll see some real big bills. The previous owner had an average bill of $240/mo our energy company told me when I signed up. The change from mechanical to the 3M-50 should help lower energy costs. Program has been set and wifi-enabled so I can tune it.

Thanks for the tip on the filter, I'll look under the vent pipe to see if I can find a door or slot for it. I believe the duct cleaning was in addition to servicing the unit. I saw the bill the owner paid was $680 so I think its a bit high for just ducts?

I showed the photos I took to an HVAC guy he said he hasn't seen one of these in ages and told me these were built to last, all solid steel and heavy. The unit does a pretty good job at heating the house. It is a monster, when it runs the gas meter needle spins fast, the roar of gas being burned and the radiant heat being emitted in the boiler room is tremendous. We have a new CO meter and test it monthly. I also installed a fire extinguisher near by.

The next simple change I will do is seal the seams around the duct work and tape it then wrap it in insulation in the unconditioned crawl space .

As for a new radiator it will have to wait a bit, we are paying two mortgage's (old house is being put on the market) and the money we could be saving for a new furnace is paying both bills. We also don't want to sell our stocks or dip into savings.

[pitogo]

I finally got down and dirty with it. I found where the filters are. There is a bank of 4 filters feeding two huge blowers powered by 1 motor. The heat exchanges look massive and solid. I retired two broken humidifiers and sealed their openings. One was plumbed but not actually doing anything but consuming electricity and the other was not connected to a water line sitting on the return side. Our January utility bill was $435 keeping it 71 during the day and 67 at nights and 66 whenever we were away in 07660. The house is leaky and a better fix would be to install new better insulated windows and pockets.

[lawrosa]

Our January utility bill was $435

Good Lord!!!! Thats half my gas bill for the whole year!!!!

Mike NJ

[Jay11J]

What is that green/teal thing on top/middle of this?

[Grady]

My guess is it is the evaporator coil. Note what appears to be Insultube toward the bottom/left of the picture labeled "overall view".

[Jay11J]

Kinda figured it was.. But what way is the air flow going??

[Grady]

Based on the gas line going in on one end & the vent coming off the other, I'd say the air flows into the evap coil on the gas pipe end then out the top. It would appear the plenum on the vent end would be the return? Certainly a strange looking set up. Maybe pitogo will come back & explain.

[Muggle]

The house is leaky and a better fix would be to install new better insulated windows and pockets.

Read more: Monster furnace DIY or find a Pro?

That a good approach; you'll need a much smaller furnace once the house is retrofitted.

Air sealing and adding insulation (to the attic, at least) have a good return on investment.

Windows don't have a good roi - don't count on significant savings unless they're single pane (if they are, shrink wrap is a good temporary solution) or leak badly. It's a good idea to get the frames sealed though.