Squeaky Thatcher from the fifties

markamft

I’ve lived with a fifties-era Thatcher oil furnace for 30 years. Now it makes a loud squeaky squealing sound when the fan is on. My service provider replaced the fan belt but no dice. Can the entire fan motor assembly be replaced? Or should I shell out the $$$$ to replace the whole system? No interest in converting to gas as we have an oil water heater and newish electric range and washing machine.

pecmsg

Blower bearings, motor bearings?

My math says 70 years not 30.

markamft

The furnace was built in 1950 but I didn’t buy the house until 1992. 😉
Yes, my service diagnosed bearings. I’m wondering if the blower and motor can be replaced. Two different HVAC company technicians recommend replacing the entire unit; $7k at the low estimate.

pecmsg

Find what size furnace is needed. Manual “J”
Find what the existing ducts can handle. Static pressure test TESP.

markamft

We have a contract with an oil company. Their man, who I’ve worked with before, recommended a Williamson PLB098DDRW. He said it was a good replacement for what’s there, with minor ductwork needed. The house is small; 1 1/2 story cape, 2 bedrooms. Heat pumps were installed in 2019 for AC; one in the main space and one mini split each in the bedrooms. We mostly use them for AC only, but they will heat the house if the temps are above freezing. Hope that addresses your post…

HVACNUT

Are the pulleys perfectly aligned? 
Is it the right size belt?
Was the belt tightened to the amp draw of the motor?
Motor mounts secure?

What burner is on the furnace? With a furnace from the 50's, it likely has a steel chamber so it's not even a retention head burner.

Briefly looking at the furnace you mentioned, it can be fired as low as .50 GPH (70K BTU) and as high as .70 GPH (98K BTU). If you did a Manual J as suggested, you'd probably realize you need maybe 50K BTU's. But a .50 GPH input is probably as low as you'll find. The Williamson also has an ECM blower motor which is a plus.

We don't discuss pricing here, but if it were me in your situation, and I had a nice tax refund coming, I'd be all over that Williamson. 

bburd

At 70 years years old, you have more than gotten your money out of that furnace. Even if you replace the blower bearings and motor, the heat exchanger might perforate shortly thereafter, and then you're going to need a new furnace anyway. I'd go with the new Williamson.

markamft

Thanks for the comments! Both HVAC organizations were helpful and tried what they could. The belt was replaced, then replaced again. They had a hard time finding the right belt. The motor mount was jerry-rigged. It was quiet for about three hours. Nice and toasty even in the single digits, but the squealing started up again and robbed me of a good night’s sleep. We’re putting the down payment on the Williamson Monday. Meanwhile, earplugs…

markamft

Update: someone screwed up and they sent a Williamson PLB 210, not the PLB 098, as ordered. The crew got it into the basement before they (thankfully) realized the mistake. They've taken that furnace out of the basement, but say "we can't get" the original model I agreed to and are putting in a Spirit (buy Thermo Pride) VLR-DBP. I'm not happy that I'm not getting what I agreed to, but they say it's a comparable furnace...I guess either way it's better than trying to live with a 1950s model on its last legs.

markamft

Guess what? The Spirit is too big to fit through the door to the basement...

pecmsg

It can be broken down.

markamft

They discussed that (breaking it down) amongst themselves (at this point five the men were on site). For whatever reason they decided against it. In the end, they thought a Rheem unit would fit, but it’s only one inch narrower.

EBEBRATT-Ed

It's called a tape measure and a little pre planning.

They couldn't figure out the furnace wouldn't fit before they got to the job?

EdTheHeaterMan

I hope the old Thatcher is still operational. That would be a real problem if the old furnace was already in the scrap yard. Hold back at least $500.00 from your final payment. You might want to check the difference in the Williamson and the Rheem

markamft

Thanks for the feedback. No one bothered to check the model number on the new furnace against the order. Whoever put it on the truck and then took it off the truck messed up. The only caught the mistake when they saw how powerful the unit was. Thankfully the caught the mistake before hooking it up.
The Spirit they tried as a substitute for the original unit was much taller, but by that point the crew was desperate to try anything, tape measure be damned. I will say it was close.
As a lay consumer I’m not sure how to compare units, but the outputs are comparable on all three units (I told them to hold off on the Rheem while I considered my next move).
Yesterday I had another contractor over who suggested an LG hyper heat system. But we already have three Fujitsu mini splits that we installed three years ago for cooling. We’re using them to heat the house now that the Thatcher is in the landfill…and we are told the unit we ordered in the first place will be here in about a week.

markamft

Upshot: the original contractor, who has serviced my home for many years, came through with the correct unit, a Williamson PLB098. The house is now toasty, but this thing is LOUD. It reminds me of a giant propane heater I had in a camp in Vermont. Ironic, since the reason we decided to replace the old unit was the squeaking. But the advantages are clear. Still, we will use our Fujitsu heat pumps more often now. I appreciate the feedback.