What WILL Work Then?

I recently moved into my first house - an early 70s "raised bungalow"
with a 150-amp ITE Blueline Panel, connected to a Pony Panel. The
'lower-level' of the house is a self-contained 800-sq ft "in-law
suite". Electric baseboards heat both levels (17,000 baseboards-only
watts, in total).
I've hired a very capable and conscientious (IMO) licensed electrician
to do a couple of smaller electrical renovations, but we have a
project coming up on which I don't feel we're communicating very well,
and I feel uneasy: Electrical suppliers are telling me the materials
my electrician has asked me to buy really aren't appropriate ... and
that makes me wonder if they're safe.
In the upper level (1200 sq ft - where I live), I'd like to install an
older wall-mount 220-v air conditioner, which I'd been using in my
previous apartment: "230/208 v, 60 HZ, 1 PH, 16,000-BTU, 11-amp,
2250-watt, wall-plug Tandem Blade 15 Amp (ie: two horizontal 'eyes';
and a vertical 'mouth'), 1989-model Electrohome - Model Number
A1602A." The Owners' Manual for the unit specifies #14-gauge
receptacle wiring.
A service-technician who recently "tuned up" the A/C unit told me:
- the unit's built-in thermostat is "220-volt ... there's no step-down
transformer"; and
- he had no idea if the unit was a "single stage" or "two-stage".
The installation will involve a couple of minor wrinkles:
we intend to bypass the unit's built-in thermostat, and install a
programmable wall-mount thermostat (preferably 7-day) some distance
away from the unit; and
the unit will be wired to the Pony Panel, onto a circuit to which one
(or two?) upper-level ONLY baseboard heaters are already connected.
The thinking is that, once "a/c season" arrives, the individual
thermostat(s) of theses baseboard(s) will be turned to "zero" - and,
regardless, there is no circumstance in which both the a/c unit and
baseboard-heaters will both be 'on' - something I alone will be
completely in control of. This idea does make sense to me - but then I
have no "technical" basis on which to consider it.
The Installation My Electrician Proposes
- my purchasing a wall-mount thermostat: "reverse-acting, double-pole,
line-voltage for 220v air conditioner"
- my buying 12-2 gauge wiring for:
Run One: "connecting the thermostat directly to the A/C unit" (44
feet); and
Run Two: "connecting the thermostat directly to the Pony Panel" (62
feet).
The Problem
- Electrical suppliers say they're "not even sure it's possible to
bypass the unit's thermostat." My electrician says it's "a piece of
cake" - though all he knows about the unit is that it's a wall-mount
220-volt with wall plug-in.
- They're also telling me the thermostat I'm looking for either
doesn't exist - or "the programming function would be scrambled by the
arcing of the 220 volts". Bad idea.
- They all say we should be installing "a relay and step-down
transformer, to be able to use a low-voltage AC thermostat". My
electrician's response to all this was: "Naw - we don't need a relay.
Just get the thermostat I told you, and right amount of 12-2 wire".
And now, this morning, the electrician's let me know that he'll "pick
up everything - save you the trouble".
I know this guy means well - and I do trust him. But no one seems to
think his plan makes sense except him. If I can't make sense of all
this, I've decided I'd rather forget the whole idea than install the
unit without a wall-mount thermostat. Unfortunately, the most
informative Web sites from which I could learn something aren't really
helpful - they assume I already know the difference between a volt and
an ampere. I don't.
If you're read this far, I thank you for your time ... any feedback
from you would be really appreciated.
Reply to
Jacques
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If the thermostat your electrician is planning on using is designed to switch the 240v line under the type of current an A/C presents I have to believe the manufacturer is providing the separation necessary to isolate the electronics. The key here is how the thermostat was designed and what it is listed as being suitable for. There is nothing magic about a low voltage thermostat cludged together with a relay and a transformer that can't happen under one cover. As for bypassing the unit thermostat, I assume all he will do is turn the control up full blast and let the auxillary thermostat control the turn on and off like a switch to the receptacle.. With your typical "window shaker" there are not going to be any problems with this since the internal thermostat simply switches the line.
Reply to
Greg
| I recently moved into my first house - an early 70s "raised bungalow" | with a 150-amp ITE Blueline Panel, connected to a Pony Panel. The | 'lower-level' of the house is a self-contained 800-sq ft "in-law | suite". Electric baseboards heat both levels (17,000 baseboards-only | watts, in total). | | I've hired a very capable and conscientious (IMO) licensed electrician | to do a couple of smaller electrical renovations, but we have a | project coming up on which I don't feel we're communicating very well, | and I feel uneasy: Electrical suppliers are telling me the materials | my electrician has asked me to buy really aren't appropriate ... and | that makes me wonder if they're safe. | | In the upper level (1200 sq ft - where I live), I'd like to install an | older wall-mount 220-v air conditioner, which I'd been using in my | previous apartment: "230/208 v, 60 HZ, 1 PH, 16,000-BTU, 11-amp, | 2250-watt, wall-plug Tandem Blade 15 Amp (ie: two horizontal 'eyes'; | and a vertical 'mouth'), 1989-model Electrohome - Model Number | A1602A." The Owners' Manual for the unit specifies #14-gauge | receptacle wiring.
That plug as known as NEMA 6-15P. The corresponding receptacle is NEMA 6-15R.
| A service-technician who recently "tuned up" the A/C unit told me: | - the unit's built-in thermostat is "220-volt ... there's no step-down | transformer"; and
That means it needs no separate 120 volt circuit. It's designed to operate entirely with that voltage. It does not need a neutral wire to get the 120 volts. The 6-15 does not include a neutral wire, so the plug is appropriate.
The actual nominal voltage is supposed to be 240 volts, and the A/C may be designed for it anyway. "220" is just what so many people say out of habit or not knowing the standard nominal voltage. Your power company can tell you the range your voltage should be. A good meter can test it to be sure if that is ever a concern.
| - he had no idea if the unit was a "single stage" or "two-stage".
I have no idea what that means.
| The installation will involve a couple of minor wrinkles: | we intend to bypass the unit's built-in thermostat, and install a | programmable wall-mount thermostat (preferably 7-day) some distance | away from the unit; and | the unit will be wired to the Pony Panel, onto a circuit to which one | (or two?) upper-level ONLY baseboard heaters are already connected.
I don't know what "Pony Panel" means. Maybe someone else does.
| The thinking is that, once "a/c season" arrives, the individual | thermostat(s) of theses baseboard(s) will be turned to "zero" - and, | regardless, there is no circumstance in which both the a/c unit and | baseboard-heaters will both be 'on' - something I alone will be | completely in control of. This idea does make sense to me - but then I | have no "technical" basis on which to consider it. | | The Installation My Electrician Proposes | - my purchasing a wall-mount thermostat: "reverse-acting, double-pole, | line-voltage for 220v air conditioner" | - my buying 12-2 gauge wiring for: | Run One: "connecting the thermostat directly to the A/C unit" (44 | feet); and | Run Two: "connecting the thermostat directly to the Pony Panel" (62 | feet).
So the thermostat is opening and closing the full power load of the A/C.
| The Problem | - Electrical suppliers say they're "not even sure it's possible to | bypass the unit's thermostat." My electrician says it's "a piece of | cake" - though all he knows about the unit is that it's a wall-mount | 220-volt with wall plug-in.
If your add on thermostat controls the power to the receptacle the A/C is plugged in to, then you just set the A/C unit thermstat to its lowest setting.
| - They're also telling me the thermostat I'm looking for either | doesn't exist - or "the programming function would be scrambled by the | arcing of the 220 volts". Bad idea.
Such a thermostat can be made, but I don't know if any exist on the market. My guess is that it would run about $100.
| - They all say we should be installing "a relay and step-down | transformer, to be able to use a low-voltage AC thermostat". My | electrician's response to all this was: "Naw - we don't need a relay. | Just get the thermostat I told you, and right amount of 12-2 wire".
If such a beast exists.
BTW, be sure the wire has a 3rd ground wire in it. Such wire would be one of the following:
Black + Red + Green Black + Black + Green Black + Red + Bare Black + Black + Bare
You may be able to get by with Black + White if the white wire is well marked as black.
| And now, this morning, the electrician's let me know that he'll "pick | up everything - save you the trouble".
Hope he gets the right thermostat.
| I know this guy means well - and I do trust him. But no one seems to | think his plan makes sense except him. If I can't make sense of all | this, I've decided I'd rather forget the whole idea than install the | unit without a wall-mount thermostat. Unfortunately, the most | informative Web sites from which I could learn something aren't really | helpful - they assume I already know the difference between a volt and | an ampere. I don't.
My concern is that he might get a 120 volt thermostat, power it between one hot wire and the ground (not neutral because there is no neutral) and leave one hot wire live when the thermostat kicks off.
The concern is not about there being only one switched wire, but rather, about the thermostat getting 120 volts with the ground wire instead of the neutral wire. If that is the type of thermostat, it might be OK if the wire is 12-3 from the panel to the thermostat to get 120 volts the legitimate way.
The single hot wire is still a hazard, too, even though without a thermostat you'd have both. The reason is, with one disconnected, there would be the belief that the receptacle box is dead, when in fact it is not. Electrical codes require 2-pole switches/contractors for 2-pole circuits like that. A thermostat would be no exception.
If he gets a genuine 240 volt thermostat that has a 2-pole contactor, then it should be fine.
Reply to
phil-news-nospam
After thinking about this a bit, it might not be a good idea to cut the power to the A/C unit via a thermostat. The reason is it also cuts the power to the blower. This can result in the A/C unit freezing up often.
Reply to
phil-news-nospam
I've never had a window or through-wall mounted A/C freeze the coils when the compressor and fan were turned off together. There's simply not enough residual cooling left in the system after the compressor stops. In fact, the evaporator should warm slightly since its pressure increases as the refrigerant pressures equalize in the unit.
The only time I've ever seen one of these freeze the coils was at my first job after college. Whenever it rained, water ran off a low spot in the flat roof directly onto the window A/C unit in my office. The condenser squirrel cage blower had no drain, so it blew lots of water onto the coils. That brought the refrigerant cycle temperature down so far that the evaporator went below freezing, iced up and blocked all airflow. We came to call that building the Temple of Dust.
Mike
Reply to
Mike Lamond
THE reason older room air conditioners kept the fan running was to get quicker response to room temperature: the fan draws in the room air past the sensor bulb.
BUT the continuous air flow ends up putting some of the moisture recently condensed back into the room. The fan also draws a significant amount of power.
IOW: it's better to just completely turn the unit ON or compretely turn it OFF. Mounting the therrmostat some distance from the unit avoids short cycling. It's a good arrangement if you do the hardware right.
Reply to
John Gilmer
| I've never had a window or through-wall mounted A/C freeze the coils | when the compressor and fan were turned off together. There's simply | not enough residual cooling left in the system after the compressor | stops. In fact, the evaporator should warm slightly since its pressure | increases as the refrigerant pressures equalize in the unit.
Have you in fact tested this in many repetitous cycles? I've never known it to happen in one or a few cycles. But I did have this happen a couple times on an A/C unit I was frequently powering off and on. That was with a particular unit which never did it otherwise. Some other units have been known to freeze up simply due to excessive use. I do think you should at least check this with your unit.
Reply to
phil-news-nospam
Thanks to all (and especially to Phil) who took the time to make thoughtful comment. Here's where I've ended up, based on advice of a well respected supplier:
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. Install a Relay With Built-In Transformer made by Aube Technologies
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- Model Number 840T.
. This Relay will be installed directly inside the AC Unit.
. Will also install a new Programmable Heating/Cooling Thermostat by Aube
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: Model Number TH-141-HC-28.
. This thermostat is NOT powered by low-voltage, but by two AA batteries.
. Will use #18 or #20 wire for connection between the Thermostat and the AC Unit (44 feet)
. Will use use #14-2 or #12-2 wire for connection between the AC Unit and the electrical Panel (16 feet)
. Operations: AC Unit will operate as before/as normal. Manual dials on the AC Unit will all be functional as before/normal (ie: temperature-level setting ... blower-fan settings) - with one possible/probable exception: May not be able to run "fan only" ... may be that fan will only function if/when compressor operates at the same time.
. Sounds good to me. I expect that means I'm missing something.
Reply to
Jacques

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