Installed new tstat for heat pump, nothing works

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  #1  
Old 11-15-15, 07:17 PM
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Installed new tstat for heat pump, nothing works

I've got a 30 year old heat pump that I don't use very much but when I need it, it's fine. It had a York Honeywell FuelSaver that had a rotary dial to set desired temperature that was becoming very inaccurate. This unit did not have a battery. So I replaced it with a Lux TX 1500 which does have a battery. I use the Lux in another part of my house, liked how it worked and had a spare. The Lux TX 1500 isn't very new but thought it would meet my needs.

Got it wired in and now nothing works. No heat, cooling or fan on manual. I've attached a photo and wiring diagram of my original thermostat as well as a photo and the suggested wiring diagram of the new thermostat.

Couple of things I noticed. Before I took the old thermostat off, I checked the voltage from R - red to X black and got almost 12 volts, thought I should be getting 24 volts. But now that I think of it, I might have had the voltmeter on dc, is transformer ac? Now, with the wires hooked up, I don't appear to have any voltage. I had turned the power off while I was doing the rewiring and yes I turned the power back on. I have jumpered the red to green but the fan did not start. I've seen mentioned the I should have either o or b connected but not both. Looked like my old thermostat had both connected.

From reading other posts, I think I need G - fan, R - power, Y - compressor and my manual says this should be jumpered to w, B - chg over. There is also an O shown as alt in my manual.

I've taken the wires off the tstat and don't find voltage either dc or ac using the red wire and any of the other wires. So maybe I need to get in the crawl space and check at the transformer.

And how do I identify which wire or wires I need to connect for the change over, reversing valve?

I've attached photos of the old/new tstat and also wiring diagrams. These were .png files now labeled as .jpg. Not sure if they have been converted or not.

woops, not sure what happened with attachments, will repost attachments

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Old 11-15-15, 07:20 PM
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hope the attachments make more senseName:  oldtstat.jpg
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  #3  
Old 11-15-15, 08:25 PM
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The B terminal is often used for 24 volt common. Connecting common to B in most modern thermostats will pop the low voltage fuse in the indoor unit or cook the transformer if a fuse isn't present.

I cannot read the model number of the old thermostat. Can you type it in?

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Old 11-16-15, 08:16 AM
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Thanks . It's a York (Honeywell) Fuel Saver Q6300 And yup, I've either blown the transformer or fuse. So now I need to get into the crawl space to see what's going on.
 
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Old 11-17-15, 11:39 AM
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I would see what black and blue connect to at the indoor unit. It is unlikely that blue is for a reversing valve with your application.
 
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Old 11-18-15, 09:57 AM
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Thanks, good tip. Just sent an email to york asking for clarification on their terminal connectors. manual just lists terminals r,b,y,o,w,x,and g with no explanation. if i don't get an answer, then i'll get into the crawl space and pull the panels off to see what's going on.

Also, i will use a lux tx 9100 u instead. better documentation. i'll keep the tx 1500 more my main gas/ac unit as a backup.
 
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Old 11-18-15, 11:19 AM
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We can give you a clarification of connection terms but what we need to know is what colors are on what terminals. That is an arbitrary decision partially made based on known standards and the installers whim.
 
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Old 11-18-15, 12:13 PM
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okay, the 2nd attachment i sent in the beginning of the thread shows the old stat with the wires. i've reattached inline this time just that attachment. the terminal labels colors are

g - green
w/e - white into w jumpered to e
b - blue
o - orange
y - yellow
r - red
x - brown or black

I'm pretty sure i know what the terminal labels mean with today's stds but not sure what they did on the unit when it was installed in 1986

like why are both b and o connected?

there is no battery in the unit, so it needs a common, is that x?

will the unit switch automatically to resistive heating or only when i use the manual switch for em ht?

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Old 12-16-15, 11:46 AM
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pkay, finally got back to this. i decided to buy a newer tstat lux 9100u that had better documentation on how to wire with a heat pump. I also found on the lux website a terminal connection cross reference chart that listed conversion from york to lux tstats. What was confusing me was that I had both o, b, and x terminals connected on my york. what worked was to connect the o to o, b to c and leave the x disconnected.
 
 

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