Daikin HP on heat mode

[Latte]

Good Evening Gents,

Outdoor: Daikin RVF7W1
Indoor : 2 X FHYC125B7V1

Called out for an E0 fault (Outdoor saftey)
Cleared codes, reset and run 3.8 suction 18 bar Discharge on heat mode.

Filters clean, Indoor fans on high, set at 25 degrees C
Condenser clean, Both outdoor fans flat out

Discharge seems high to me, any ideas or do they run at these pressures on heat.

Regards

Fatboy


PS R22

[frank]

Hi Raymond

I think that the outdoor unit must be a RY250F7W1

The RY means heat pump
The 250 = 25kw
F = F Series
7 = Japanese internal code?
W1 = 3 phase

If you have had an E0 fault then one of the internal relays has gone open circuit in either the compressor or cond fans. Next time you go out to it and bfore you switch off check for continuity on the GREY wires connected to the pcb. You should be able to measure 240v on both pins.

When you reset the mains you lose the ability to find the break.

[aeb200]

I have had this before on similar model
Condenser fan getting hot and intermittantly tripping unit
There is a thermistor attached to fan which breaks when fan hot.

The way to find the fault is run the unit up in test for a bit - then if you have an infra red thermomter point it at the fan motor - if one is getting hot this may be your problem note you cant just order a fan motor as lead and slave are different!!!!!
if you don't have infra red thermometer you can turn unit off and use a touch probe, or wait till unit trips then measure the continuity of the grey wires

[Latte]

Hi Raymond

I think that the outdoor unit must be a RY250F7W1

.

Hi Frank,

As per usual, you were correct with the model number.

I was a bit worried about the HP on heat. is 18/19 bar within spec. It seamed a bit high to me

Regards

Ray

[martind]

E0 - this is quite curious error code.
Directly connected to the following safeties:
- Thermal protector of fans
- Thermal protector of the compressor
- Overcurrent relay
So check the temperatures, the higher pressure could indicate the thermal protection problem.

But sometimes it also occured at:
- power supply problems (very often) - instantaneous power failure (in one case I found low-voltage protection on power supply)
- the indoor unit is demanding cooling, but the outdoor unit does not cool from any reason
- cold junction on outdoor PCB (on the left top side, there is a small 2-pin connector (I think it is red, but I am not sure, maybe white) and this was a little bit loosen in maybe two or three cases - soldering solved the problem in some cases for me, in some cases we have changed the PCB)

I would also check (but this is low probability, if the system has benn running for couple of years), if the system is configured as Twin, and the wiring is correctly made, because we had many problems with it.

[frank]

Hi Raymond

18/19 barg is normal (49C) running pressure on heating mode. Don't forget that the discharge gas has to travel all that way along the pipework to the indoor coil before giving up it's energy to the room :)

I've seen Mitsi's running at 340psig (23barg). Mitsi's tend to run hotter than Daikin in my experience.

Try to look at temperatures and not pressures on your gauges :)

[Latte]

Thanks Frank,

I think i am back at the site on Monday doing a maintenance so i can recheck it again. There didn't seem any heat inside the unit when i was there as i had to take the cover off to fit guages, no ports outside the unit and no gauges built in.

I have seen some units with gauges on the cover and there are blanks on them to put them, do you know whats the story with these (are they an optional extra)

regards

Ray

[frank]

I have seen some units with gauges on the cover and there are blanks on them to put them, do you know whats the story with these (are they an optional extra)

If you see a unit with gauges fitted it more than likely came from SpaceAir - they fit them as standard. Pillinger/Cooling Services etc only used to fit them as an extra. Space say that it saves the tech having to take the covers off and fit gauges on every service visit, which always results in a small loss of gas and over time this can affect the system operation as gas charge is critical on VRV/VRF


There didn't seem any heat inside the unit when i was there

In heating mode then you wouldn't expect to find any heat in the outdoor coil (evaporator) :)

[Latte]

Hi Frank,

What i meant about the heat was that when a compressor gets that hot is goes out on klixon you can normally feel it. Nothing on this one as was the case with the fans. I will recheck it on Monday to see if either is overheating.

Well done to Space for fitting gauges, although i suppose the gauges use flare connections and these could possibly leak it does save time and a lot of ****ing about if the gauges are already fitted.

Regards

Ray

[martinpsullivan]

E0 i have found i thermistors for compressors or condenser fan motors on daikin units you have to test all 4 thermistors if a vrv or 2 for a split these will reset when temp drops on faulty part though.

[martinpsullivan]

Check condenser fan capacitors as i get many go at this time of year causing E0 code for a condenser fan.