Two indoor units on a single zone

[sparky89uk]

Hi everyone,

I have a quick question which you might be able to assist in.

I was looking to add an additional indoor AC blower to an existing single zone system.

Basically the customer has one indoor unit at the moment in a room and they are wanting to add another to duplicate the exact operation of the other at all times to assist in balancing the temperature in the room (like a slave indoor unit). The second indoor ac unit will NOT require any setting apart from to copy the exact operation of the master unit. E.g if the main unit is switched on the secondary unit will automatically start and if the main unit is cooling then the slave will do exactly the same. The secondary unit will not need to take the temperature of room as this will be controlled my the main indoor unit.

Would it be a case of adding tee pieces to the lines and working out wiring to duplicate the operation of the other or is there more involved than this?

The secondary unit is located on the opposite side of the room and is assisting the main unit in cooling the room down to help balance the temperature overall.

All controls such as temperature adjustment, heat, cold and fan will be controlled by the master unit located on one side of the room

[hyperion]

Firstly it would depend on the overall capacity of the outdoor unit. Then in theory you might be able to get two identical capacity indoor units to work. Dependant on the make, you may be able to then install them as a twin system.
If you just try to add a second indoor unit, you will end up with a complete mismatch and whilst it may work to a certain amount, the pressures and temperatures would be completely wrong, let alone the calculation for how much refrigerant ought to be added.
If the cooling duty required is insufficient, then put a second complete system in and control both units from one controller. That would require both systems to be of the same make and electronically compatible.