Split-unit issues

[antio]

Hello,

We have a split unit installed. The outdoors unit sits 2 floors above and the indoors units are 2.5 and 3.5 KW respectively. This is a new installation and we have 2 issues:

1. When I power on the big unit I can hear the refrigerant running through the pipes of the small unit. It's a distracting sound, especially if the small unit is off, as it's in a small quiet room. However, when I am running the small unit, the bigger one is quiet.

Is this normal and is there any way of stopping it, if we don't want to have both units on? (e.g. a valve to stop it from running to the smaller unit if it's off?)
(if it matters, the order is this: external unit -> big internal -> small internal)

2. The big unit will heat, but will not cool. Again I can hear the refrigerant running through the small unit and if I power the small unit up it blows out very cold air. However, the big unit is blowing out room-temperature air (maybe a tiny bit cooler). I find that odd, as heating works fine on both units.

Any ideas would help, before I call the engineers to have a look. Basically, I'd like to know if they've messed up during installation, so I can be prepared. I'd really like to address the noise issue, as it's quite distracting.

Many thanks in advance.

[al]

if you select heat on both units will both heat? both units must be set to same mode (auto not recommended for this type of install). the noise you hear in the small unit is refrigerant, with regards to noise with out knowing what brand or model number of unit it is hard to say if normal or not, why not ring the installer and ask?

[antio]

if you select heat on both units will both heat? both units must be set to same mode (auto not recommended for this type of install). the noise you hear in the small unit is refrigerant, with regards to noise with out knowing what brand or model number of unit it is hard to say if normal or not, why not ring the installer and ask?

Hi Al, thanks for replying. Both units are set to the same mode. Heat works fine, both heat together or either one can heat individually just fine. It's only with cool air that the large unit isn't working. I experimented a bit more and it's not working when it's on on it's own and the small unit is off. Is this normal? I wonder if the refrigerant is running through the small unit (which is off) and not going through the big unit at all. In heat more it works fine on its own though.

They are Mitsubishi Electric (small unit: MSZ-SF25VE2).

I will ring the installers on Monday, just wanted to do my homework first, as I'm not an expert and if they say "sorry, noise can't be fixed" or "they both need to be on" I won't know if that's true or not.

[install monkey]

either crossed pipe or crossed interconnect

[antio]

either crossed pipe or crossed interconnect

Excuse my ignorance but wouldn't that also mean they wouldn't work in heat mode? Either of them on its own works fine in heat mode. Either of them on its own doesn't work in cool mode - only when they are both on...

Either way it sounds like an installation fault, so I will be calling them on Monday (unfortunately we tried them in Winter and only tested heat...). Thanks!

[install monkey]

you have 2 indoor units a 3.5kw and a 2.5kw- do you have 2 outdoors or 1 outdoor (with 4 pipes connected)

[antio]

you have 2 indoor units a 3.5kw and a 2.5kw- do you have 2 outdoors or 1 outdoor (with 4 pipes connected)

Correct re: indoor units and there is only 1 outdoor unit (split type). Not sure how many pipes connect to the outdoor unit though (I'd have to go through another property to check).

[install monkey]

if its a mitsubishi elec then if you run only 1 indoor then you hear gas gurgling through the unit thats off.
if its a multisplit then you have to deisgnate 1 as the master- this will determine the mode- heat or cool- whichever mode this is in - the other unit will only do the same mode, model number for the outdoor will give us more info

[antio]

if its a mitsubishi elec then if you run only 1 indoor then you hear gas gurgling through the unit thats off.
if its a multisplit then you have to deisgnate 1 as the master- this will determine the mode- heat or cool- whichever mode this is in - the other unit will only do the same mode, model number for the outdoor will give us more info

Thank you, that's quite disappointing about hearing the gas gurgling - it's rather loud in a quiet room!

I don't have the model number to hand, but will call the installers on Monday - both units are in cool mode, but only work when both on. That can't be right.

Thanks for your help!