HVAC System 20 Years Old, Time to Proactively Replace??

[Deere Dude]

We snowbirded for 8 years from central Wisconsin. We had a new house and had one small room with the water softener, pressure tank and water inlet to the house in there. It had shelves for paint and canned goods. We insulated that room and put a couple small milk-house heaters in it on separate circuits and put the 2 sump pumps on separate circuits.

When we left in November we drained all the water, blew air through the lines and sent a shot of RV antifreeze through all the pipes. Then we shut the furnace off and didn't worry about it until March of April.

We did have someone come by every couple weeks just to make it look like it was lived in. We did that for 8 years with no ill effect.

 

[kenmac]

I had nothing but failures when the new units came out... lots of unhappy tenants and many service calls... no hot water in the morning is one sure fire way to get people angry... especially when it happens over and over again.

It got so bad the manufacturer refunded my money... I was going to file with every agency State and Local as well as go to the media... to get my refund I had to use tin snips and cut out the Product decal for each heater and send them to the manufacturer.

The Warranty Service company stopped servicing them because the way they were compensated a call back on a previous warranty call was paid almost nothing.

I switched Brands to Bradford White and not a single issue going forward...

Have no idea if the other heater company ever got the product corrected or not and have no interest in finding out.

On a separate note... I still have manual 1920's floor furnaces that work today as well as they did 90 years ago... they have standing pilots and a "Key" to turn on the burner... turn key on you get flame... turn off and the flame goes out...

Yeah, whirlpool tired that pay nothing for warranty repairs with me too. I told them to find someone else in the area. they called me back a week later and paid my going rate LOL



I cut my teeth on millivolt systems. They manufacture their electricity to operate. Most about 750 millivolts. You get a little corrosion on any of the wire connections, and it would kill your M.V, and no heat !
The later ones (floor furnaces) that came out had all types of safety devices (limit switches). These limit switches would get hot and kill power to the unit and shut it down before it ever got warm in the home lol.
The thermostat would be set at 70, but the temp in the home would only be 60, except at those limit switches....
People would always want me to take those switches out of circuit. I couldn't do it for liability reasons. I never bypassed a safety device

 

[ultrarunner]

Yeah, whirlpool tired that pay nothing for warranty repairs with me too. I told them to find someone else in the area. they called me back a week later and paid my going rate LOL



I cut my teeth on millivolt systems. They manufacture their electricity to operate. Most about 750 millivolts. You get a little corrosion on any of the wire connections, and it would kill your M.V, and no heat !
The later ones (floor furnaces) that came out had all types of safety devices (limit switches). These limit switches would get hot and kill power to the unit and shut it down before it ever got warm in the home lol.
The thermostat would be set at 70, but the temp in the home would only be 60, except at those limit switches....
People would always want me to take those switches out of circuit. I couldn't do it for liability reasons. I never bypassed a safety device

Most of what I have predates all the new stuff... my oldest central furnace dates from 1922... a big basement millivolt gavity monster that just keeps working providing silent warmth throughout the home.

My biggest problem with millivolt happens when someone replaces the Mercury Thermostat...

During the big earthquake years back power was out of almost a week... my millivolt furnaces and pilot light stoves/water heaters never missed a beat...

One of my friends decided to be proactive in 2003 and replaced all his 12 year old kitchen appliances... gave the old ones to me for hauling them away.... and I put them in a rental and so far no problems... he has not been so lucky... problems with the new cooktop, stove and dishwasher

 

[kenmac]

Most of what I have predates all the new stuff... my oldest central furnace dates from 1922... a big basement millivolt gavity monster that just keeps working providing silent warmth throughout the home.

My biggest problem with millivolt happens when someone replaces the Mercury Thermostat..

I have worked on some of those old spider (as we called them) monster gravity furnaces that were converted from old coal fired to nat gas. Most of those are all gone now days.

Millivolt furnaces use a millivolt T.stat. not a regular T. stat

 

[mcfarmall]

To the OP: Maintain it properly and run to fail. The old saying holds true, "They don't make them like they used to." Your new 10k furnace and A/C will probably only last 10 years. The new heat exchangers are made paper thin so they heat up quickly and "save fuel" but they also burn through quicker and don't last through all the thermal cycling.

 

[pmsmechanic]

Millivolt furnaces use a millivolt T.stat. not a regular T. stat

But they do work with a regular thermostat. Ask me how I know.

 

[ultrarunner]

I have worked on some of those old spider (as we called them) monster gravity furnaces that were converted from old coal fired to nat gas. Most of those are all gone now days.

Millivolt furnaces use a millivolt T.stat. not a regular T. stat

Yep... never a problem with mercury stats...

Tons of problems with snap action stats on millivolt... a simple temporary fix is to burnish the points with a business card... 99% of the time that would allow sufficient current to flow and all is good...

Not uncommon here in the SF Bay Area for a furnace to sit idle for 9 months of the year and then the first cold snap and nothing works...

The central furnace in question is almost identical to the coal fired model it is just here natural gas has been a staple for a very long time... the only difference in the model is a "G" added.

Have to say it is still my favorite... silent unobtrusive heat with little dust.... and it simply "Just" works...

I guess I'm firmly in the camp of keep using it until you can't

 

[RobS]

I wouldn't replace it but certainly would be setting money aside for the day.

We lucked out last fall. Furnace died, heat exchanger corroded through. Thankfully, it had a lifetime warranty but they no longer made that model. York (kudos to them) gave us a whole new furnace but we had to pay the install. Still a lot of money but could have been far worse.

Furnace was "only" 16 years old. Seems the newer stuff just doesn't last all that long...

 

[kenmac]

But they do work with a regular thermostat. Ask me how I know.

they will work but they use up more millivolts. it doesn't take much resistance and you'll use up all millivolts. The old round honeywell mercury millivolt T.stats didn't have a heat anticipator to eat up your millivolts.
I haven't worked on a MV system in a long time. I had to repair gas logs last week for a friend that operated on MV, and a light switch

 

[3930dave]

To the OP: Maintain it properly and run to fail. The old saying holds true, "They don't make them like they used to." Your new 10k furnace and A/C will probably only last 10 years. The new heat exchangers are made paper thin so they heat up quickly and "save fuel" but they also burn through quicker and don't last through all the thermal cycling.

"Efficiency" gains.... gotta love 'em. Most of the efficiency gains have been in emptying our bank-accounts with capital-equipment expenditures. Equipment costs aside (oligopolies anyone ?), skilled labour costs/truck rolls keep going up every year.

Same on the AC side..... coil wall thickness is down, pressures are way up, as is compressor rpms. Kaaaccchhhing ! :greedy: if you are an HVAC contractor....

Rgds, D.