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-   -   hvac control line dead, can I go wireless (http://www.diychatroom.com/f17/hvac-control-line-dead-can-i-go-wireless-73761/)

hnations 06-15-2010 01:26 PM

hvac control line dead, can I go wireless
 
Here's the problem: my hvac tech says I have a bad wire between air/handler thermostat outside to the condensor. rewiring thru a condo will be a nightmare so I'm wondering if the honeywell redlink wireless systems will work. the problem is I need to cycle the condensor on/off AND control the fan plus heat, where the controls still work AND those controls are across the home from condensor. The only thing NOT working is the 24 v control line thru the house from air handler to condensor. could i use TWO receivers? one to control the condensor from the utility room and one to replace the existing thermostat near the air handler? I'm quite confused, even after 10 hours of research.

hennyh 06-15-2010 05:27 PM

Maybe I'm missing something, but why don't you just diagnose and repair where the wire is broken? Why is rewiring the entire system needed?

Wires just don't decide to break in the middle of wall cavities. The break is likely at the point of connection or outside to the condenser where it could have been damaged. These areas most in harms way could easily be inspected.

I think some diagnoses is needed before you replace the entire control system.

hnations 06-15-2010 05:47 PM

That's a very good point. I thought of that after the previous hvac tech left also. This'll be the first thing I mention to the new hvac tech from a different company coming tomorrow. the previous guy didn't think of checking the wiring aside from right at the contact points at both ends. Nice guy but not an electrical expert, by any means. Thanks

yuri 06-15-2010 06:04 PM

Very common for the wiring to get damaged at the outdoor unit by weedwhackers, dogs, rodents chewing it. If he does not know wiring what else does he not know.:eek:

hnations 06-15-2010 06:15 PM

Another excellent point. One reason why a different company was called (he also managed to let the smoke out of a new transformer he had just put in.....). Not that I haven't done similar things myself to different kinds of equipment :).

yuri 06-15-2010 06:24 PM

We all have to learn somewhere, just let the rookies learn on the "other guys" unit and not mine. LOL:laughing:

biggles 06-15-2010 07:10 PM

before anything get a meter and where the wires come out of the condo headed to the condenser get down and razor the brown wrap ..split it and skim each wire then see if you have 24Vs coming out... OR if you have spare wires just change both with the exsisting at both ends WITH POWER OFF color doesn't matter..if it isn't a heat pump you only need 2 low voltage wires going out.....transformer is in the furnace not the condenser

hnations 06-15-2010 07:58 PM

More good advice, thanks. The transformer I mentioned is just a small step down to 24 volts one that is in the air handler to power the fan, and maybe some other things, dunno. no furnace, heat is from hot water heating air.

biggles 06-15-2010 08:21 PM

OK.so you only have and need a pair of low voltage wires out to the condenser can you check for 24vs with a meter.call the AC in and shut the disconnect out at the condenser ..reason just want to see if the compressor contactor is pulled in or read the 2 low voltage wires on each side of that contactor..if you don't have a meter ..have to call a tech in $$$ it could be a break in the line,a coil burnt on that contactor, a safty swiitch open....but with that disconnect off the pressures should eqaulize and make both(if you have them).

hnations 06-15-2010 09:36 PM

Thanks biggles. I think that makes sense only I'm not sure about the "disconnect" at the condensor. there is a fuse box thingie, is that what you're referring to? I can use a volt meter but beyond that and simple dc circuits (and some simple ac ones), I'm reasonably useless. It does appear that the logic here is simple though, if you ignore the magic going on INSIDE the outside unit and all kinds of safety switches etc. Do you know Clarke's Law (think its the first one, but can't remember): "any sufficiently advanced technology is indistinguishable from magic"........

biggles 06-16-2010 05:21 AM

so if you have a digital meter set it for AC and check that brown wrapped coming out of the condo wall for 24Vs...yes on that fuse box same as a disconnect..keeping in mind the 24Vs comes from the air handler TR thru the stat.the disconnect outside is for the compressor and fan only within that condenser.if you remove the panel on the condenser you will see where the brown wrapped 24Vs lands on the contactor or to the pressure controls...if you remove them there and leave them hanging not touching anything...you can read 24Vs there.IF you do then the problem is in the condenser not a broken wire

hnations 06-16-2010 10:02 AM

Thanks again biggles, that makes perfect sense to me. I'll let you know what I find.

hnations 06-16-2010 12:54 PM

I'm now convinced that the 24v controll line is dead, as I tested it at the conduit box on the outside wall, after separating the lines that go from there out to the condensor, say again, damn. one extra conductor, but no signal thru it either.
hvac guy is here, but he probably wont' know, so i'll ask here too: could a remote wireless with reciever in the nearby utility room control THAT line, while using the current thermostat (or a separate remote receiver replacing it) to control the fan and heat. the current system will turn on the fan and heat and it seems silly to pull new wire at enormous inconvenience just to control the on/off to the condensor. if the remote system wires for the OTHER parts of the system could be pulled which ever way they need by adding a load or resistors, or whatever is needed, this seems to make some sense to me. but what do I know? that's why I'm here.......

hnations 06-16-2010 01:14 PM

found the problem! it was, embarassingly, a brain-to-keyboard error MOSTLY (but not entirely) by own fault. only real problem was twice blown transformer.
but I really appreciate all the great feed-back I got on this forum, THANKS, .as I really learned a lot
h.

biggles 06-16-2010 03:46 PM

coooooooooool:thumbup: ...might consider installing an in-line auto fuse to one side of the 24V side of tht TR in the air handler 3 amps glass tube fuse should do!


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