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Cedare
21-12-2008, 03:21 PM
Can anyone help? I have been given a brand new RAC 60NH4 Outside unit (24 000 BTU) and RAK 50NH5 Indoor Unit (17 000 BTU). Can they be used together, given the mismatch in capacity.

The refrigerant pipes on the outside unit are 6,3mm & 12,7mm, whereas the indoor unit is 6,3mm and 9,5mm, so I would need to use a reducer to connect them.

Thanks,

ewgeny
22-12-2008, 11:46 AM
I don't thik that's good idea, but you can try. Electric should be matched. If you do this, it's better to keep indoor fan in med. or high.
Why you don't try to change any of units, to be 100% sure?

rude
22-12-2008, 11:50 AM
it wont work.

On heating it will keep tripping out on High Pressure

multisync
22-12-2008, 04:10 PM
it wont work.

On heating it will keep tripping out on High Pressure


Not a fan of Hitachis by any means but two things spring to mind.

1 The few I've done have dip switches for different indoor units
2 Will the inverter not stop it from tripping by slowing down when it starts to ramp near its hp set point?

Just asking

Multisync
London

eggs
22-12-2008, 04:23 PM
I'm not an expert at any of this but........you do see it the other way around quite often where there is a high sensible heat load. Bigger indoor unit than outdoor unit.

Seems to work fine, why not the other way around??

Eggs

frank
22-12-2008, 07:26 PM
With a Daikin split, the outdoor will handshake the indoor pcb but if a different capacity setting is read then an error will be generated.
This is why you must fit a new capacity resistor to the indoor board when you change the pcb. The capacity is set via software in the factory during production but must be set manually on a board change.

I doubt any mis-matched indoor / outdoor combinations would work, no matter what the make, due to the software programming.

eggs
22-12-2008, 09:38 PM
With a Daikin split, the outdoor will handshake the indoor pcb but if a different capacity setting is read then an error will be generated.
This is why you must fit a new capacity resistor to the indoor board when you change the pcb. The capacity is set via software in the factory during production but must be set manually on a board change.

I doubt any mis-matched indoor / outdoor combinations would work, no matter what the make, due to the software programming.

I'm sure your more well up on this kind of thing Frank, but i can assure you i have installed at least 20 Mitsi Elec, 5hp cassettes to 4hp outdoor units into laboratories in the last 12 months.

They all work fine.

eggs

al
22-12-2008, 10:34 PM
these are the domestic hitachi range, not dip switchable as far as i know, also they appear to be different generations, NH4 and YH5.

The YH5 supports a hard wired remote that the YH4 doesn't.

these things are cheap as chips, buy the matching indoor
although i don't ship that far!!:D

Al

Thermatech
22-12-2008, 10:51 PM
Eggs

Q are the ME high sensible 4hp outdoor connected to 5hp indoor units type A control R407c / R410a or the older type K control R22 systems.

Can you advise model numbers ?
Do ME provide full warrnaty for this non standard combination & high sensible application.

eggs
22-12-2008, 11:07 PM
Evening Thermatech


Eggs

Q are the ME high sensible 4hp outdoor connected to 5hp indoor units type A control R407c / R410a or the older type K control R22 systems. Presume type A, as they are on 410a, sorry can't help more as i never spec MEUK for any of our jobs so i don't know much about them. On these jobs we just hang, pipe, wire, suck, blow and go.

Can you advise model numbers ?I see if i have copies of the commissioning sheets on tomorrow
Do ME provide full warrnaty for this non standard combination & high sensible application.Pass? we have done them labour only for a specialist Lab contractor


I'll dig out what info i can tomorrow.

Cheers

Eggs

nike123
23-12-2008, 08:09 AM
I know that some Toshiba outdoor inverters are for more than one capacity and, only thing you need to do, is to change some jumper configuration on outdoor PCB to match indoor and outdoor unit.
Here they are (indoor and outdoor unit) selling them independently, but if you order more than 2-3 unmatched pairs , they immediately suspect that you want to spare some money buying cheaper, lower rated outdoor unit model (and patching it to higher capacity for same lower price) :o:p, and doesn't allow that order.:mad:

beagle
24-12-2008, 11:35 AM
Eggs

Do ME provide full warrnaty for this non standard combination & high sensible application.

Officially, no they don't. You only have to supply the model of the unit the fault is on, so for instance if you need a new indoor pcb the model number of the indoor unit and invoice no. of the original order are all you would have to supply, they then supply the relevent spare. If they're on the ball and look in detail at the original order and see that it contains mismatched units, they can question it but ultimately the only way they can prove the systems on site are mismatched is by going there and taking a look themselves, I don't yet know of any instance that any manufacturer or distributor has gone to these lengths to void a warranty claim unless it's a site with multiple failures.