Stulz ASD 1052

[rude]

Hi guys

does anyone know much about these units? I am currently having an issue with a comp2/hp fault.

I have bridged out the compressor overload as I thought this may have been going off. But the unit still fails. I then thought the hp wire connections were loose so I tightened the terminals. But the unit still fails. The hp switch has a manual reset button which has never activated so I am wondering why this fault keeps occurring.


I have check all wire connections and made sure everything was tight. Could it be that he pc board is faulty? I'm out of ideas.

[bigor_2]

I've never seen Stulz. But I think you can check Input/Output in submenu of controller and take a decision.

[Mick13]

its been a while since i have worked on one of these units.... but about 5 years ago i was working on one in the presence of a technician from stulz themselves, and i vaguely remember him telling me that a hp fault doesnt just mean a hp fault (ie high pressure) but it can also mean a bunch of other things, like overload etc, its almost like a universal fault code.

id be seeing what other safetys it has and be checking them....

i think they have a separate lp fault so u can probably rule that out....

good luck!!

actually the more i think of it, i think they may have a high discharge temp sensor/safety, which i think he said ties in with the hp fault.... maybe its slightly short of gas?? somewhere to start anyhow....

[anxr62nv]

its been a while since i have worked on one of these units.... but about 5 years ago i was working on one in the presence of a technician from stulz themselves, and i vaguely remember him telling me that a hp fault doesnt just mean a hp fault (ie high pressure) but it can also mean a bunch of other things, like overload etc, its almost like a universal fault code.

id be seeing what other safetys it has and be checking them....

i think they have a separate lp fault so u can probably rule that out....

good luck!!

actually the more i think of it, i think they may have a high discharge temp sensor/safety, which i think he said ties in with the hp fault.... maybe its slightly short of gas?? somewhere to start anyhow....

Hi Mick, there is also a habit for Stulz and other manufacturers to wire the compressor protection modules into the HP control circuit. So if this module trips (located in the Copeland compressor terminal box) it will also show as a HP fault. Look specifically at the control voltage to, if your getting more than 10% above 24V, the compressor protection modules can fault due to high control voltage. So basically, you attend for a HP fault and the units in alarm, and yet you press the HP reset button and no 'click'. Seen this more than once on Stulz units, particularly if the site voltage is high and the Stulz control transformer has not been tapped appropriately ie 400V.

Hope this helps.

[rude]

Hi Mick, there is also a habit for Stulz and other manufacturers to wire the compressor protection modules into the HP control circuit. So if this module trips (located in the Copeland compressor terminal box) it will also show as a HP fault. Look specifically at the control voltage to, if your getting more than 10% above 24V, the compressor protection modules can fault due to high control voltage. So basically, you attend for a HP fault and the units in alarm, and yet you press the HP reset button and no 'click'. Seen this more than once on Stulz units, particularly if the site voltage is high and the Stulz control transformer has not been tapped appropriately ie 400V.

Hope this helps.

That helps but I have already bridged out the compressor overload so it's not in the circuit. The only thing I have connected is the hp switch bit the manual push button has not tripped.

[FreezerGeezer]

If it's a (Danfoss iirc) dual HP switch, there might be a second, pressed metal push button hidden under the front cover of the switch, top centre.
Silly question I expect, but have you made sure there's no manual on site? The only Stulz I've worked on so far had one stashed in the PABX room nearby.

[The Viking]

Measured the control voltage before and after the switch?

[Neddy]

Has it got a discharge transducer? If so it may be reading incorrect causing the HP fault. When in fault check the voltage either side of the HP switch and at the PCB. If this is ok it could be a possible faulty PCB.

[rude]

I have been told to check the 24v voltage to make sure it isn't low or too high.

the problem with checking the voltage when it fails is I am never there its always tripping at 3 in the morning or 10 at night and it might run for 4 days straight then trip. It's really intermittent.

i bridged out he hp switch today to see if it runs all night.

[bigor_2]

do you have electric diagram for this unit?

[rude]

I wish It did. I'm going to try change the pc board and see what happens.

[RusBuka]

Last HP fault that is not the real HP was on Daikin Chiller. Big RED button "Alarm cut off" make HP on all counters.

[rude]

I have by passed all the safety circuits and leaving the unit run for a few days and see what happens. The pc boards for these units are very expensive.

[install monkey]

i wouldnt shout too much about bypassin safety circuits- if it goes bang then deny everything.

I have by passed all the safety circuits and leaving the unit run for a few days and see what happens. The pc boards for these units are very expensive.

[rude]

It would be a good outcome!