# Honeywell screen went blank



## hvactech126 (Nov 11, 2010)

chk wiring connections... and tighten both at stat and at EIM. Sounds like display is going out. inside the stat is a watch battery but only to retain memory.


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## Master Brian (Apr 24, 2009)

Well, I haven't checked this evening, but so far it's stayed on that I see since pulling it off the wall and putting it back on. I will check the connections as well. I suppose as long as it's just the display that goes out and if the unit still functions, I'll be ok. I just worry about loosing it and loosing heat at the same time. I have standard t-stat's I can replace with, but prefer not to have to re-wire one, just to wait a week on shipping for a new IAQ unit....


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## hvactech126 (Nov 11, 2010)

Master Brian said:


> Well, I haven't checked this evening, but so far it's stayed on that I see since pulling it off the wall and putting it back on. I will check the connections as well. I suppose as long as it's just the display that goes out and if the unit still functions, I'll be ok. I just worry about loosing it and loosing heat at the same time. I have standard t-stat's I can replace with, but prefer not to have to re-wire one, just to wait a week on shipping for a new IAQ unit....


that stat has a 5 year warranty


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## Master Brian (Apr 24, 2009)

hvactech126 said:


> that stat has a 5 year warranty


I was wondering about warranty, that is good to know! Thanks!


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## Dave Carney (Apr 25, 2009)

FWIW, when my system was installed the installer did not push the unit back onto the mount far enough before he left, and we had similar weirdness as soon as he was gone. He came back and in pretty short order determined what the deal was. Pushed it all the way on, no problems in a year and a half.


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## SKIP4661 (Dec 3, 2008)

I suspect the furnace is opening the limit switch due to an overheating situation thus killing the low voltage to the furnace and stat. You may want to check your filter and make sure all registers and grills are clear and open.:thumbsup:


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## beenthere (Oct 11, 2008)

If your furnace is a condensing furnace, and its condensate drains to a condensate pump. See iif the safety switch of the pump is wired to break the Power to the EIM. If so, your pump is having a problem.


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## Master Brian (Apr 24, 2009)

SKIP4661 said:


> I suspect the furnace is opening the limit switch due to an overheating situation thus killing the low voltage to the furnace and stat. You may want to check your filter and make sure all registers and grills are clear and open.:thumbsup:


I'll check that. The filter is due to be replaced as the display is flashing such, I'll go ahead and replace it even though the current filter hasn't been in the full 30days yet, I had checked it a few days before it said to change and it still looked pretty good, but maybe I'm wrong. It hasn't happened since I pulled it off and pushed it back on, but certainly don't want to overheat the furnace......

All drains of the furnace & a/c lead to a sump pump.

Thanks for the replies!


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## Focker (Jun 3, 2012)

I just went through this problem over the weekend. The system is 9 mo old so I didn't mess with it. The tech fixed it in 30 sec after finding a blown 3 amp automotive fuse on the circuit board inside the furnace. I felt stupid that I didn't see it but then again any chance of me NOT voiding a warranty is a good thing!


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## beenthere (Oct 11, 2008)

But what caused the fuse to blow.


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## how (Feb 26, 2011)

Just to advise of a new wrinkle to consider.
I don't know if smart meters are being installed elsewhere but some of the young twits installing them in my area have been causing 24V issues with furnaces, doorbells and appliance clocks.


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## Focker (Jun 3, 2012)

beenthere said:


> But what caused the fuse to blow.


A possible short...but the tech seems to think the 3 amp fuse is under sized from the manufacturer. He replaced it with a 5 amp. He said if it pops again he'll hunt down a possible short.

Sent from my mobile using DIY chat room app.


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## hvactech126 (Nov 11, 2010)

Your tech is a moron. Many systems come with a 3A fuse. Put the correct fuse back in there before you blow your transformer.


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## biggles (Jan 1, 2008)

dow you have wires on R and C for a constant 24Vs from the furnace take a Q-Tips wipe the contacts/pins with alcohol..vodka,gin,...whatever:wink: doubt a furnace hi-limit knocks it down, condensate pump might if you have one see:huh: if you have low voltage wires going to it


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## Focker (Jun 3, 2012)

I have a 5 year parts & labor warranty from the installer...I really want to keep my hands out/off of it. I have in my hands a no charge invoice clearly stating he replaced the 3 amp fuse with a 5 amp.



hvactech126 said:


> Your tech is a moron. Many systems come with a 3A fuse. Put the correct fuse back in there before you blow your transformer.


The transformer at the curb? 



biggles said:


> ...condensate pump might if you have one see if you have low voltage wires going to it


I have the pump but it's not wired to the system.


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## hvactech126 (Nov 11, 2010)

The transformer in your air handler/furnace.


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## beenthere (Oct 11, 2008)

A 40 VA transformer at 24 volts has a max continuous amp draw rating of 1.66 amps. The 3 amp protected the 40 VA transformer from surges. The 5 amp won't.


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## Focker (Jun 3, 2012)

beenthere said:


> A 40 VA transformer at 24 volts has a max continuous amp draw rating of 1.66 amps. The 3 amp protected the 40 VA transformer from surges. The 5 amp won't.


Good to know...Sounds like I better make a call.


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## Focker (Jun 3, 2012)

Well the 5A fuse popped last night. I called at 3am and left a msg so I could be at the top of the list today. A tech should be here this morning.

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