Old Toshiba Super-Multi fault

[CCLPaul]

Tomorrow morning I have a 1995 Tosh MAR-F8 outdoor unit to look at. It has an intermittent fault with an outdoor unit error code ER21. I am told this is either high pressure or high discharge temp code.
Apart from ensurring that the condenser is clear, where should I start?
Is there someone with an electronic technical manual for one of these units?
Any help this evening would be gratefully received.

[martinw58]

need to check gas charge if undercharged uint will trip on high discharge temp

[bigor_2]

E-21 High pressure error.
see
http://rapidshare.com/files/412201574/SM2PIPE_.pdf

[philjd26]

hi
in my experience of this error, as previously said;
check refrigerant amount as thermal overload will trip with high suc and dis temp.
also take a look at the inverter comp winding for earth leakage. inverter could be drawing excrssive amps.
other ones are head pressur transducer, fans, coils,non condensibles...

had many problems with that error, and can be a tricky one to catch.

best of luck

rgrds phil

[CCLPaul]

Thanks guys, looks like this may be awkward. Biggest problem is that it faults intermittently and it is in a hotel making access to all areas almost impossible at any one time. Have already started and eliminated several possibilities, hopefully get it sooner rather than later

[quigmeister]

Deal with these a lot:

Check the cables running from the hp switchs error can be caused by the cable being oxidized due to the fan in the electric panel drawing in moisture which then causes a higher resistance sometimes just remaking off the ends of the cables can rectify it but it is a pain of an error to fully get rid of.

[Loops]

OK Er21 is not only a high pressure trip.

Can also be an overheated compressor. (the HP switch and compressor klixon are in series so there's almost no way of telling which tripped)

Couple of things very well worth checking;

1. That each indoor unit does heat - MC boxes were prone to discharge solenoid coil failure which causes a high pressure trip. Later coils where fine. Symtom is indoor cools fine but won't heat.

2. Gas charge - obvious that the compressor will overheat if the gas charge drops enough.

3. Check that the capacity codes for each indoor unit are correct. If they're too low this can cause compressor problems.

Let us know how you get on.

Cheers

Loops

[CCLPaul]

many thanks for everyones help here. I followed a fault finding procedure checking all sensors etc, eventually ruling all of them out. I then removed the refrigerant, the weight confirmed a shortage of gas. I have since located the leak caused by a cracked flare nut on a Flow Selector box.
When are these manufacturers going to remove mechanical joints from their units?