Fusible link on carrier furnace

Steve Ebels

Which particular bad idea are you speaking of?

Roy Tenn

Fusible link on Carrier Furnace

Hello Gentlemen,

Went on a service call today and found fusible link on a Carrier m#58sx080-bc-1 open. This fuse link is inside the burner section. I would just like to know what is the purpose and cause of this safety to fail. I realize it probably acts as a rollout or over temperature protection,
but I jumpered it and ran the furnace for 30 mins.while
monitoring the temperature and flame-everything was ok.
Also what temperature does this safety at?
Any input would be greatly appreciated.

Roy

Glenn Harrison

Roy,

That is a flame rollout protection device. I certainly hope that you are going back to replace it A.S.A.P. as the ramifications of leaving it out are having the intake pipe melt and flames come shooting out of the furnace.

That being said, the primary reason that this would happen is a failed heat exchanger, most likely the secondary. We have come accross a few failed secondaries on the SX units in the last couple of years. The epoxy coating inside fails causing the steel to be exposed to the condensate, and rusting out. I have also been seing the R.T.V. sealant on the cell outlets falling off and resticting the cells which will cause either the gases or the condensate to back up in the HX. Carrier even had a service bulletin in the early nineties about a problem with too much RTV being applied to the secondary which would fall off and plug the openings. The other possibility is that the Inducer is failing and not running at full speed, or going off on overload in the middle of a cycle. If this unit still has the gray inducer motor on it, I would plan on replacing it if the HX checks out which I doubt.

I might be wrong, but I believe that fusible link blows in the 250ºF range, so it must have been very hot in the burner box when it tripped.

My suggestion would be to call this customer first thing in the AM and go back and pull the secondary HX and most likely condem it. You and your customer are just asking for trouble by not having that link in there, serious trouble. If you need it, the fusible link comes as the wire harness, the part number I don't know.

Glenn Harrison, Residential Service Tech

Althoff Industries Inc. Mechanical and Electrical Services

Crystal Lake, Illinois

Althoff Industries website

Steve Ebels

Glenn

You seem to have a lot of experience with Carrier so I'll pose this question to you.

I had a service call yesterday on an LP fired 58MCA080-12 Carrier. Installed 3 years ago. Serial # indicated late 1998 manufacture date. The complaint was a condensate leak from the inducer. Upon removing the inducer, (it was not the cause of the leak) I found that the 1/4" hose runing from the upper right side of the condensate pan to the trap was split, brittle and full of chalky grey chunks of stuff. I am assuming that the chunks were decomposed pieces of tube.

Have you heard of or run into this on this model and what could have caused it?

Mark A. Custis

Glenn/Steve

When is Carrie going to let this bad idea go away? I can think of no fewer than 28 factory fixes, much less the mubo jumbo about what part is which. Bunch of MEs busy here.

Thanks for the Vent>

Mark

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Glenn Harrison

Steve,

I'll admit I'm not too up on the current Carrier models as my current employer was a Lennox, and now Armstrong dealer. All of my Carrier experience is from former employer from 7 years ago. However, we have come accross a couple of MCA units that had the drain hose rot out, inlcuding my nephews which I installed 8 years ago. It appears that Carrier has used a grade of rubber that can't handle the acidic condensate. Part of the problem is that it is a ribbed hose so the condensate sits in the ribs and eats away. Now as for the grey chunks you saw, I would be afraid that those are pieces of the propylene coating in the secondary HX coming off and flushing down the drain. I would pull the inducer housing off and take a close look at that secondary. The secondary may be cooking from the propane or from being overheated from overfire. Unfortunatly, if there is a service bulletin pertaining to this situation, I am not aware of it due to not being a Carrier dealer anymore.

Hope this helps you, Steve. Let me know.

Glenn Harrison, Residential Service Tech

Althoff Industries Inc. Mechanical and Electrical Services

Crystal Lake, Illinois

Althoff Industries website

Glenn Harrison

Mark, that reminds me of when...

Carrier first came out with the MCA units and sold them as "designed by service technicians for service technicians" or something like that. I very quickly learned that I was being lied to as no knowledgable technician would have designed these things the way they were, or still are. I can hardly wait to see there new multipositon 80% units in the field and see what pieces of garbage they are.

I generaly like Sears,for tools, but frankly they can have Carrier has no quality dealer should have to deal with the garbage going on at Carrier.

Just my 2 cents worth

Glenn Harrison, Residential Service Tech

Althoff Industries Inc. Mechanical and Electrical Services

Crystal Lake, Illinois

Althoff Industries website

Steve Ebels

Glenn

We no longer sell Carrier either. Very unhappy with the support from Carrier Great Lakes in Livonia. (Like none to "don't bother me, can't you see I'm too busy with this video game to help you".)

Switched to American Standard and are very happy with the product and support. Somewhat of a learning curve as the distributor is brand new to the product also and doesn't know a lot technically speaking yet. Really like what they are doing with the intelligent ignition control and trying to reduce hot surface ignitor failure.

Glenn Harrison

Yea, my bosses looked into Trane when we decided to get rid of Lennox, but were totally dissatisfied with the distributors service, so we went with Armstrong and have actually been very satisfied.

Glenn Harrison, Residential Service Tech

Althoff Industries Inc. Mechanical and Electrical Services

Crystal Lake, Illinois

Althoff Industries website