Daikin VRV 3 pipe changing mode

[multisync]

Multi,

I meant to ask you if the preheat/defrost icon is displayed on remotes when unit changes/stops heating?

Also there is no need to select test mode just make sure all units are set to heating only mode.

Is there no way you beg borrow or steal a service checker for a couple of hours? This would save you so much time, allow you to see exactly what’s happening and the auto address of the problem indoor if my suspicions are correct. Hotels are always a head ache trying to get access to rooms (BTW you really need to get a checker for VRV fault finding).

If not do have an old centralised controller? This could be connected at the outdoor and would allow you to lock the operation mode and to have control of indoors units from outside. However you still need brief access to programme group numbers if this has not been done in the past.

I can confirm the pre heat logo comes on during this problem. Would this mean the short cycling is not likely the cause?? He did say with 4 indoor units on (out of 10) the cycling happend less frequently.He did not have full access to all 10 rooms -hotels eh?

Sadly I attempted to buy a checker from a friend of a regular here. All was agreed until he stopped answering my call(s)..not too sure what went wrong there...

[VRVIII]

I can confirm the pre heat logo comes on during this problem. Would this mean the short cycling is not likely the cause?? He did say with 4 indoor units on (out of 10) the cycling happend less frequently.He did not have full access to all 10 rooms -hotels eh?

Sadly I attempted to buy a checker from a friend of a regular here. All was agreed until he stopped answering my call(s)..not too sure what went wrong there...

The preheat icon will be displayed when ever the outdoor is in equalization/defrost/oil return/preheat. I would defiantly check for short cycling if the problem is occurring every 20minutes or so.

[multisync]

The preheat icon will be displayed when ever the outdoor is in equalization/defrost/oil return/preheat. I would defiantly check for short cycling if the problem is occurring every 20minutes or so.

We will deffo check that first.

Thanks for all the assistance I will get back with this either way...

[VRVIII]

We will deffo check that first.

Thanks for all the assistance I will get back with this either way...

Hi Multisync,

Did you get to the bottom of why the units was changing mode?

[multisync]

Hi Multisync,

Did you get to the bottom of why the units was changing mode?

Crumbs we are having so much trouble on that site it's not funny

On another system they have been waiting for a new inverter compressor. That had a U4 error over the weekend. Our guy went to site, played around checking if all indoors had power on etc. Suddenly it came back on.

Back today to start the reclaim and compressor change but were stopped before starting as another system was not heating properly (historical bad airflow design) + they wanted to have another look at the U4 error (no point changing the compressor if it won't run anyway.)

However half way through that one and a worker noticed oil dripping through the ceiling tile another system had split a liq line! So the compressor/investigation never got started.

The change over system faulting was only noted by the engineer who was looking at another system in error. He mentioned it as a problem but the site guy's are saying they haven't had one complaint from that area so it's being left till we can get the rest sorted...

[VRVIII]

Crumbs we are having so much trouble on that site it's not funny

On another system they have been waiting for a new inverter compressor. That had a U4 error over the weekend. Our guy went to site, played around checking if all indoors had power on etc. Suddenly it came back on.

Back today to start the reclaim and compressor change but were stopped before starting as another system was not heating properly (historical bad airflow design) + they wanted to have another look at the U4 error (no point changing the compressor if it won't run anyway.)

However half way through that one and a worker noticed oil dripping through the ceiling tile another system had split a liq line! So the compressor/investigation never got started.

The change over system faulting was only noted by the engineer who was looking at another system in error. He mentioned it as a problem but the site guy's are saying they haven't had one complaint from that area so it's being left till we can get the rest sorted...

Multi,
It sounds like you’ve had one of those days
At least you didn’t need to dig your way through the snow to get up the street on the way home

U4 errors can be real pain on older installs, especially when it’s an intermittent fault.


You will probably be aware of the most common reasons for a U4;

• Mains power off at indoor/bs/outdoor
• Loose live or neutral connection
• Mains power has been switched off/on but system fails when reinitializing (turn power off/on again and hold down reset button for 10sec)
• Bad connection on F1F2 comms lines
• Mice or rats chewing into comms cables!
• If it’s an R22 KJ outdoor unit the small green interface pcb that f1f2 cable connects to has been known to cause probs (not applicabe for 407c).
• Faulty indoor/bs/outdoor main PCB (never had this with intermittent U4 error tho)
• K series units can be very slow to recognize a U4 error
• U4 errors will auto reset when comms are reestablished

Let me know how it all works out

[multisync]

Multi,
It sounds like you’ve had one of those days
At least you didn’t need to dig your way through the snow to get up the street on the way home

U4 errors can be real pain on older installs, especially when it’s an intermittent fault.

You will probably be aware of the most common reasons for a U4;

• Mains power off at indoor/bs/outdoor
• Loose live or neutral connection
• Mains power has been switched off/on but system fails when reinitializing (turn power off/on again and hold down reset button for 10sec)
• Bad connection on F1F2 comms lines
• Mice or rats chewing into comms cables!
• If it’s a KJ outdoor unit the small green interface pcb that f1f2 cable connects to has been known to cause probs.
• Faulty indoor/bs/outdoor main PCB (never had this with intermittent U4 error)
• K series units can be very slow to recognize a U4 error and
• U4 errors will auto reset when comms are reestablished

Let me know how it all works out

Took me 1 1/2 hrs to go 3 miles this afternoon.

We've had rats chew the comms cable in a hotel once and a few of the others here and there. This is a strange one and we can only hope that it holds till Christmas.

The install is only just (and I mean 3 weeks just) 3 years old. It's sad they are failing like this. I won't tell you what the UK facilities Director thinks of Daikin after this and an even worse site up north somewhere....


Just to cheer you back up I am mid swap on a Tosh SHRM: 3 condensers multiplexed and so far in 2 years 3 compressors failed out of 6 !