Sully Posted June 16, 2014 Report Share Posted June 16, 2014 My turn I guess... I have an all electric house with an air handler and heat pump. Both units are only 4 years old. I have a Honeywell digital thermostat that is 4 years old as well. The entire system worked fine all winter. 2 weeks ago, when it was a bit warmer, the A/C was working fine as well. I was off work all last week and kept the A/C off the entire time. And of course since I'm back at work this week, the wife and kid "are going to be too hot this week and want the A/C on". Anyway, I go to turn it on last night and get nothing. The thermostat display works. It says "Cool" and when I switched it on it gave me the "Wait" indicator. I hear it click like it's working, but nothing happens. I flipped all of the Handler & Heat Pump breakers. Nothing. I pulled the thermostat off the wall and noticed one of the AAA batteries was expanded and leaked at the bottom end. The contacts had some corrosion on them, but it wasn't terrible. I pulled the batteries and scraped the contacts off. I put new batteries in it and the system continues to do nothing. I've been doing some reading and my wife spoke to a friend whose husband does HVAC for a living. He said that 99% of the time it's not the thermostat. He said it's most likely a failed board, capacitor, or something of the like. I kind of feel like it may be the thermostat due to that battery leaking. I know we have some HVAC pro's on here, so I'm looking for some input on what to check before I drop a ton of coin on a service call. The first thing I'm going to try tonight is replacing the thermostat. If that doesn't fix it, I'll return it. Thanks! Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 Do you know where the board is? Is it easily accessible? Have one person stand at the thermostat and cycle the AC on/off while you're standing right infront of the board. Listen for the Relay(s) to click on and off. Also listen for relays on the thermostat itself to click on/off (just re-read, sounds like the thermo relays are clicking on/off). Thats a start, im sure someone with more experience will chime in. PS - Don't get electrocuted. Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 The first thing I'm going to try tonight is replacing the thermostat. If that doesn't fix it, I'll return it. Have you ever replaced a thermostat on a unit that has a heat pump? It can be somewhat confusing. Quote Link to comment Share on other sites More sharing options...
Cordell Posted June 16, 2014 Report Share Posted June 16, 2014 You need to figure out which two wires behind the thermostat turn on the A/C and tie them together. If the A/C comes on you'll know its the thermostat. Otherwise the capacitor in the outside unit is a very likely thing. Sorry I don't know what wires are what, I have never worked as an HVAC tech, hopefully there is some type of labeling. Quote Link to comment Share on other sites More sharing options...
Sully Posted June 16, 2014 Author Report Share Posted June 16, 2014 Have you ever replaced a thermostat on a unit that has a heat pump? It can be somewhat confusing. The current one is the 2nd thermostat I've put in this house. Quote Link to comment Share on other sites More sharing options...
Sully Posted June 16, 2014 Author Report Share Posted June 16, 2014 Do you know where the board is? Is it easily accessible? Have one person stand at the thermostat and cycle the AC on/off while you're standing right infront of the board. Listen for the Relay(s) to click on and off. Also listen for relays on the thermostat itself to click on/off (just re-read, sounds like the thermo relays are clicking on/off). Thats a start, im sure someone with more experience will chime in. PS - Don't get electrocuted. Would this be the board on the handler or the board on the heat pump? Quote Link to comment Share on other sites More sharing options...
Sully Posted June 16, 2014 Author Report Share Posted June 16, 2014 You need to figure out which two wires behind the thermostat turn on the A/C and tie them together. If the A/C comes on you'll know its the thermostat. Otherwise the capacitor in the outside unit is a very likely thing. Sorry I don't know what wires are what, I have never worked as an HVAC tech, hopefully there is some type of labeling. Good idea. The wires are labeled and I'm sure I can find something online about the wiring to test this. Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 Would this be the board on the handler or the board on the heat pump? Handler (inside), it should have 3-4 relays on it. Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 Good idea. The wires are labeled and I'm sure I can find something online about the wiring to test this. Theres some universally accepted color-coding system for HVAC wiring. IE red crossed with green will always turn the fan on, etc. You can find it online. Quote Link to comment Share on other sites More sharing options...
Mr. Jones Posted June 16, 2014 Report Share Posted June 16, 2014 Theres some universally accepted color-coding system for HVAC wiring. IE red crossed with green will always turn the fan on, etc. You can find it online. Unfortunately, installers don't always use the right colors for he right functions as most times there are excess wires. I'd go by the actual terminal (IE: R/C/Y/G) first vs color. http://i.imgur.com/1Uz6joK.jpg Quote Link to comment Share on other sites More sharing options...
XChris1632X Posted June 16, 2014 Report Share Posted June 16, 2014 The wires you are looking for are red and yellow (generally). Yellow runs the compressor, the problem is that a heat pump could operate in cooling or heating without energizing the reversing valve depending on the brand. Regardless you can jump them and test the outside unit. Just use a pair of needlenose pliers. Does the air handler blower come on? If the blower Doesn't come on then you likely have an issue at the air handler or the thermostat. 1 out of 500 or so calls is usually thermostat related with this type of thing but it can happen. Quote Link to comment Share on other sites More sharing options...
Sully Posted June 16, 2014 Author Report Share Posted June 16, 2014 So I touched red to yellow; nada. Then I touched red to green (fan); nada. Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 YOUR TRANSFORMER BE OUT BRO Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 That or your board is toast. I had similar issues (nada with jumping various wires) turned out to be the transformer. Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 16, 2014 Report Share Posted June 16, 2014 CAREFULLY check for 24v on the low-voltage side of the transformer (i'd throw the breakers, disconnect the low-voltage side, attact a Volt Meter, then throw the breakers back on). Transformer should be right near the inside control board. Quote Link to comment Share on other sites More sharing options...
Sully Posted June 16, 2014 Author Report Share Posted June 16, 2014 Pulled the panel off the handler. Pulled the fuse off the board to see that it's bad. Going to get new fuse... brb. Quote Link to comment Share on other sites More sharing options...
Sully Posted June 16, 2014 Author Report Share Posted June 16, 2014 BOOM! Up and running again. Thanks for everyone's help. Yet again, CR comes through. Quote Link to comment Share on other sites More sharing options...
ForeverMaker Posted June 16, 2014 Report Share Posted June 16, 2014 nice. Quote Link to comment Share on other sites More sharing options...
SRTurbo04 Posted June 16, 2014 Report Share Posted June 16, 2014 Good to hear you got it going! Quote Link to comment Share on other sites More sharing options...
smokin5s Posted June 17, 2014 Report Share Posted June 17, 2014 woot woot! love the easy fixes! Quote Link to comment Share on other sites More sharing options...
MattKatz Posted June 17, 2014 Report Share Posted June 17, 2014 Im betting pops a fuse again this week......Anyone wanna take me up on that? Quote Link to comment Share on other sites More sharing options...
acklac7 Posted June 17, 2014 Report Share Posted June 17, 2014 Im betting pops a fuse again this week......Anyone wanna take me up on that? This man taught me everything I know. TEST HIM, DO IT! :gabe: - Thanks again Kyle...3 Summers now and A/C is running Ice Cold/without issue. Quote Link to comment Share on other sites More sharing options...
Sully Posted June 17, 2014 Author Report Share Posted June 17, 2014 Meh, I think it'll be fine for a while. Quote Link to comment Share on other sites More sharing options...
XChris1632X Posted June 18, 2014 Report Share Posted June 18, 2014 999 out of a thousand a 3 amp fuse blows for reasons other than just a junk fuse. Quote Link to comment Share on other sites More sharing options...
MattKatz Posted June 19, 2014 Report Share Posted June 19, 2014 999 out of a thousand a 3 amp fuse blows for reasons other than just a junk fuse. Bingo. Quote Link to comment Share on other sites More sharing options...
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