Safe to replace A/C unit's wired 240v power cable with standard powerpoint & 3-prong plug?

Forums › Home Workshop DIY › Safe to replace A/C unit's wired 240v power cable with standard powerpoint & 3-prong plug?

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Klipspringer

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#981757 7-Feb-2014 12:17

Yes agreed to the above. To the op if this was your own home (Or renting and you own the appliance) its 100% legal.

Bung

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#981779 7-Feb-2014 12:49

Klipspringer: Yes agreed to the above. To the op if this was your own home (Or renting and you own the appliance) its 100% legal.

There is no provision for renters, they don't own the house. The landlord may own the house but he doesn't live in it so he isn't covered by any diy provisions either.

kenkeniff

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#981802 7-Feb-2014 13:23

The debate over what is/isn't legal should probably be raged along in this thread insted: http://www.geekzone.co.nz/forums.asp?forumid=4&topicid=138971

I realise the way I posed the question caused some ambiguity about what exactly I was asking.

It should have been something more like;

I have an A/C unit wired directly into the wall (as pictured/described).

Question 1: Why are some home appliances are wired into the wall without a plug (my oven, dishwasher, A/C)?

Question 2: In my case would a (properly trained and certified) electrician be able to (with the landlords consent) re-wire it so that it had a standard power plug into the wall?

Question 3: If so, would it be possible to place a standard power plug timer between the A/C unit and wall plug to turn it off at a certain time?

...that is all. But I guess trolls gonna troll..

mclean

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#981851 7-Feb-2014 14:39

It's hard to say what would happen if you cycled the mains power to the fan-coil on and off. That type of fan-coil is never controlled that way - they are always controlled using control inputs. There will be one input from a local controller/sensor in your room (usually on the wall), and possibly another from the building controls to tell it whether there's hot/chilled water available, etc.

If the controller/sensor in your room has an on/off switch or a fan speed switch then it should be easy to incorporate a timer in the control circuit. But you're going to need the as-built control drawings to figure it out - the controls on this sort of fan-coil are different from project to project. If it's a well managed hotel then the engineering manager will have the as-built drawings. You won't be able to do it without his help anyway so you should talk to him/her first.

A picture of your room controller/sensor might give a clue.

If the hotel was built in the last 15 years the HVAC is probably controlled by a Building Management System - in which case what you want may be a software tweak.

gzt

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#981872 7-Feb-2014 14:51

kenkeniff: Question 1: Why are some home appliances are wired into the wall without a plug (my oven, dishwasher, A/C)?

Ovens, because they consume more far power than a standard plug is rated for.
Dishwasher, usually not direct wired IME. Usually goes into a well hidden socket, which is switched from bench level.
Aircon, because it's not an appliance. Eg; similar to ceiling fan or ceiling lighting.

kenkeniff: Question 2: In my case would a (properly trained and certified) electrician be able to (with the landlords consent) re-wire it so that it had a standard power plug into the wall?

Hard to tell. There was an electrician earlier in the thread offered an opinion on that.

kenkeniff: Question 3: If so, would it be possible to place a standard power plug timer between the A/C unit and wall plug to turn it off at a certain time?

Really your objective is #3 installing a timer. So there are a couple of different approaches you might take to that problem:

1. Have aircon specialists install a purpose built aircon timer in place of the on/off control. Might be less than you think and probably the best way to go relationship wise with the rest of the building/bc. It would not surprise me if other tennants/owners have done that already.

2. Have an electrician install a timer panel in place of your existing on/off control.

Edit: #3 if the Aircon has it's own fuse/rcd inside your apartment maybe an electrician could consider installing a din rail timer alongside.

Hope that helps!

gzt

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#981887 7-Feb-2014 15:10

kenkeniff:I enquired with the maintenance guys about getting a digital wall-pad with timer however they reckoned you'd need to replace the whole control unit too so didn't bother with that.

Oops. I see you have explored that option already to some extent.

kenkeniff

628 posts

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#981892 7-Feb-2014 15:22

mclean: ...

A picture of your room controller/sensor might give a clue.

...

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gregmcc

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#981899 7-Feb-2014 15:39

kenkeniff: The debate over what is/isn't legal should probably be raged along in this thread insted: http://www.geekzone.co.nz/forums.asp?forumid=4&topicid=138971

I realise the way I posed the question caused some ambiguity about what exactly I was asking.

It should have been something more like;

I have an A/C unit wired directly into the wall (as pictured/described).

Question 1: Why are some home appliances are wired into the wall without a plug (my oven, dishwasher, A/C)?

But I guess trolls gonna troll..

A/C unit are wired in because they are a fixed appliance - they never move, a dish washer and an over are both classed as a portable appliance and must have a plug socket arragement, If you look closly at any house in the past 15 years you will see that the oven is infact got a plug and cord attached and plugs in to the wall.

gzt

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#981910 7-Feb-2014 16:19

Looks like something from this range. This one is the closest physical match.

Described as: "3 speed fan, 1 cool (PWM) and 1 heat controller designed to be used for complete control for air conditioning systems which have Pulse Width Modulated chilled water valves"

gzt

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#981924 7-Feb-2014 16:27

Datasheet here. Edit: After reading that I can see my #2 and #3 suggestions are a lot less likely and probably in the realm of very silly ideas.

timmmay

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#981973 7-Feb-2014 16:52

How about a robot finger on a timer? Have it push the off button.

kenkeniff

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#982019 7-Feb-2014 17:47

timmmay: How about a robot finger on a timer? Have it push the off button.

Not a silly idea, it did actually cross my mind but didn't really know where to begin with it...

mclean

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#982037 7-Feb-2014 18:11

I see you have it turned right down. It might be worth doing some basic commissioning checks. If you have a good thermometer then check the following:

1    The room temperature when you're comfortable.

2    The room temperature when you're uncomfortably cool in the morning.

3    When the room is uncomfortably cool, is the fan-coil still cooling?

You can tell if it's cooling by measuring the temperature of the supply air right at the face of the supply grille, or even better just behind it. If the air coming out is colder than the room then it's cooling. Another way is to feel the chilled water pipes at the cooling coil.

If the room is cold and the fan-coil is still trying to cool then there's something wrong with the controls - either the controller is broken or not set up properly, or the chilled water valve is stuck.

Porboynz

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#982068 7-Feb-2014 19:24

kenkeniff:
timmmay: How about a robot finger on a timer? Have it push the off button.

Not a silly idea, it did actually cross my mind but didn't really know where to begin with it...

Now we are talking! How about a Lego MindStorm? It may not work but you end up with a cool toy. What about adapting a bug spray unit that has an actuator in it to spray an aerosol, they usually activate a few seconds after power up and are strong enough to squirt an aerosol. Mounting it in position to finger the on off button is the biggest challenge. There are also devices to set off a camera shutter, oh the possibilities are endless!

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