Another B&Q inverter split acting odd.

[Pinter75]

Howdy,

I sadly have one of those DIY inverter B&Q split units that decided that has decided to not play nice anymore and trip the MCB in cool or heat mode.

B&Q deny ever selling these and finding any info is proving near impossible.

It was used in heat mode last year - then pop the MCB tripped and I left it alone. Now the temps have risen I thought I would take a look at it.

The indoor unit works fine. Compressor and fan all check out along with start caps etc. I have gone over the main PCB and can't see anything obvious like swollen caps, or burn't out components.

If I disconnect the compressor & fan, I get the exact same symptoms as if they were plugged in.

This is what it is doing:

Internal unit fan on, gets upto speed. Select cool mode. Wait the 3 mins for the compressor to start.

On the outdoor PCB, the red power led comes on. Then it does 8 red led flashes and 6 yellow led flashes. After a 2 second wait it briefly starts the error code flash again and trips the MCB.

I have isolated it onto it's own 32Amp MCB just incase there was anything else on the circuit that was interfering. The MCB it was on happily for 2 years is a type B curve.

I am now stumped to know what it up with it. I am sure I have taken the fan, cap and compressor out of the loop so it can't be these.

Yeah I know that I should rip it out and get something decent, but before I do I really want to see if it is a simple fix.

I guess some of you attend these B&Q units and may have seen similar problems. Maybe all the gas is out, but until i get an engineer out to check it - this looks electrical.

The last thing I can try is to replace the MCB with a type C, because I think it is a bit trippy as our old oven would trip it too.

Any pointers or ideas to debug this would be greatly appreciated before I write it off.

Cheers!

[Pinter75]

Here are some pics of the system

[install monkey]

all inverter splits should be on a motor rated breaker- c or d type- check water in isolators,nicked wires- also inspect compressor terminals -ensure comp cover has a rubber gasket to keep out condensation.

[Pinter75]

Cheers.

I will try a C rated breaker. As far as I know there are no nicks or breaks in any wires in or to the the outdoor unit. No moisture either. I did give it a clean with some contact cleaner just in case.

One thing I have not done is remove the rubber cap on top of the compressor to have a lookie, but as the unit will trip without it connected it can't be related.

[Pinter75]

I seem to find that these units are infact GREE units. No GREE markings on the main boards, but it does use a GREE remote.

Also it is badged under other makes such as DeLonghi, YORK etc.

Seems these units are more popular in Europe.

http://www.ricambiclima.it/default.a...&category_id=1

As soon as my new MCBs arrive I will see if a C curve MCB fixes the issue - but I doubt it.

It could be as simple as I have a earth leakage in the house rather then the unit itself, debug continues :-)

[goldpau]

Before you start changing breakers is the mains cabling the correct size for the new breaker? To my knowledge (I may well be wrong) b&q only sold smaller capacity systems up to 3.5kw, these should not be on a 32amp breaker as the cabling will not be correct, a 32amp breaker requires a minimum cable size of 4mm2, dependent on the cable length from the fusebox a 'c' type breaker will normally require 6mm2 sized cable - having an oversized breaker with undersized cable is a serious fire hazard! I suspect this is domestic so you are in the realms of Part P legislation if your 'meddling with the electrics' yes it may be your house & you may be a hands on person but meddling with electrics is just as dangerous as meddling with gas, is it really worth the risk?

even if you do manage to work out the fault you have next to zero chance of finding a spare part for the system to repair it, to be perfectly honest you certainly wont regret changing the system for a decent genuine Japanese manufacturer system, yes it's a higher initial cost but they will cost less to run, last a very long time but more importantly spare parts will be around for at least 10yrs which is important considering there are zero spare parts availability for cheap systems such as b&q & those on eBay.

[Pinter75]

Hi,

I understand the cable runs and capacity ratings. The system is on a 32A MCB with appropriate cabling. I am replacing a 32A MCB B Curve which is old and a bit sensitive with an identical B curve. I will not use the C curve as I feel it is shorting regardless, and you are right about not messing, I won't start upping capacities and have an electrician booked because this could all be down to an earth leak somewhere else.

Spare parts are non existent, but until this thing proves to be a write off, I will keep debugging. Electronics I can handle, it is just a case of working out a failure pattern.

I am getting to the end of the process and if fruitless, and will be actively looking for a decent install for a small residential garage conversion/office.

[install monkey]

32a b type! bit big- usually a 16 amp breaker for a 3,5kw, 20amp for a 5 kw- 2.5mmcable can handle 20amp on a radial supply, 4mm will handle a 32a breaker- im guessing its a short run to the board
have u meggered the compressor? disconnect the wires on the comp and prove theyre all well over 1 meg ohm- 1 meg will trip a breaker if theres leakage

[Pinter75]

Howdy,

It is on a 32Amp circuit along with my laser cutter, but that never trips and is now unplugged just to make sure.

Gonna double check the compressor tomorrow, took a look at the thermal fuse and that is fine. Most of it inside is squeeky clean, including coils too.

Still does not explain why it is tripping without the fan and comp unplugged. Either there is a short in the IPM (but I can't find one), or a good old fashioned earth leak somewhere else.

Just reflowed few things on the board, but could not find anything that looks to be miss behaving.

I should have a sparky round here soon to take a proper look at the circuit.

I do remember it just dying and tripping the MCB last year when it was in reverse cycle.

I know I should bin it, but I do like to make sure that it is terminal beforehand.

[install monkey]

in heating mode it will pull slightly higher running amps

[install monkey]

nice chain- is it that rough in your hood??- we dont chain splits up in manchester!

Here are some pics of the system

[joe-ice]

4 way valve coil blown ? Is there a sump heater? The wire loom entry on the left with the foam doesnt look great if your lookin 4 a short i would start there

[Pinter75]

Hi,

Coil measures 1.8k, no short, I did try to boot it up with the coil detached a few days ago, same deal, debug leds then trip

The left hand side is ok, the foam is a bit messy because the board has been in and out a few times.

Cheers for the advice, it is certainly helping.

I will probably end up shooting a video to show what it is doing.

[Pinter75]

Lol about the chain, bit of an odd one that.

Do you know how rough Brighton is?

The previous owner chained their bike up where I installed it, so I really don't know why I run the chain through the aircon - safe to say no one has nicked the outdoor unit yet - I really wish they would tho'!

You say it will pull more amps in heating mode, well that was the last mode it was in before it started tripping. Could the compressor have overheated? I did check the thermodisc on the compressor and that is giving good continuity. I thought the thermodiscs were fuses, so continuity is good?

New MCBS turned up earlier so I will replace the old with a new - both B curves, and see what happens then.

I will try to see if the board will bootup and not trip without anything plugged in, sensors, valves, motor and comp. I have not even considered that the internal unit is at fault, that goes into cooling mode but will complain abuot a comms error with the outdoor unit disabled.

Cheers chaps.