Unbelievable Design

[Bash1803]

Not really asking any advice (although comments are welcome), just venting some frustration.

I was again called to one of our sites where a Mitsi Split A/C unit for a data comms room kept failing.
The unit itself keeps failing on high pressure but comes in on an auto reset (after pressure drops).

The facilies manager keeps complaining that the unit has not been repaired and I am maintaining that we simply can't make any repairs.

The problem is that where the outdoor unit is situated is a 10mx10m outdoor atrium, due to the position of the site, no wind can dissipate the heat as the building acts as a wind breaker blowing the wind over the atrium. Another thing that does not help is the other 34 or so condensing units packed into this tight space.

Today, the ambient was 21'c or there abouts when I responded, I measured the air temp in the atrium to be 40'c, sometimes in excess. The air coming off of the Outdoor coil was 56'c. The suction temp was 10'c, the liquid was 44'c and the discharge was a stupid 102'c!!!!
It was also 6 degrees under it's design temp (supposidly) and was already pulling more than its Full Load Amps.

Another thing is that did not help is the fact the unit was on R407C, and after checking the serial no. with Mitsi, they told me it was an old R22 unit.....:eek:

Aside from employing someone to keep hitting the reset on the controller each 10 minutes or so, there is nothing else I can do (short of relocating it)....

I would just like to know 1. If there are any other service engineers who have been put into such a situation because of rubbish design or installation
2. Does anyone have any advice?

Cheers

[The Viking]

Biiig fan to bring in fresh air in to the compound!

(No, not a joke, I've seen it done!)

[nike123]

My advice is, that you find as much as possible cleaver ways to charge every arrival at that site, and if possible, make yourself more payable job at every arrival.
This is not problem of you, and probably also of original contractor. That is problem of deaf investor, who don't want to spend money for designated unit/s for that purpose. Give him what he deserve!:cool:

[Bash1803]

My advice is, that you find as much as possible cleaver ways to charge every arrival at that site, and if possible, make yourself more payable job at every arrival.
This is not problem of you, and probably also of original contractor. That is problem of deaf investor, who don't want to spend money for designated unit/s for that purpose. Give him what he deserve!:cool:

Excellent, I do like the way you are thinking but the site is about 130 miles from me, so being called out at 3am is a pain anyway, no matter how much it is worth!

[Daikin=Overated]

Not really asking for any advice............does anyone have any advice???

Which is it mate, theres loads of decent people on this site only too happy to help if you need it?

J

[Daikin=Overated]

Either way....

Pressuming theres no other maintenance related issues to either indoor/outdoor units then-

I'd blow out the condensor coil with OFN (fire hoses in the vacinity will work just fine-be careful not to kill the electrics though).

I'd reclaim the R407c charge, weigh it out, and double check the pipe run/vertical seperation before re-charging with fresh gas.

R407c being the mad isotropic blend it is, can loose it's chemical composition and ultimately efficiency over a period of time due to a number of factors above and beyond my understanding i'll hold my hands up, but the long and short of it is contamination within the system to my understanding. I've resolved a lot of issues by refreshing the R407c charge over the years.

Or finally consider flushing the system, and return to R22, it's a completely different gas to R407c.

I'd want to undertake all of the above before writing the system off.

[wambat]

I believe you have an overcharge. The sub cooling is 22*F and should be between 10/15 *F so it's reducing the condensing surface and running hi discharge pressure. The discharge temperature at 215*F is not unreasonablr but would be lower if the charge was corrected

[Larry2]

My advice is, that you find as much as possible cleaver ways to charge every arrival at that site, and if possible, make yourself more payable job at every arrival.
This is not problem of you, and probably also of original contractor. That is problem of deaf investor, who don't want to spend money for designated unit/s for that purpose. Give him what he deserve!:cool:


I have to respectfully disagree. You can tinker with a bad job forever, but never achieve customer satisfaction. Customer satisfaction sets your reputation, regardless of who created the design mistakes that called you to the job. You need to identify the mistakes (unless there is just a bad part) and offer solutions. Tinkering on a bad job won't advance your lot.

I think one needs to provide the customer with value, regardless of bad choices made in the past. That also means not taking on obligations for a bad job that proceeded your visit. If you can correct the problems without excess cost, (for instance move the condensor to a better spot) you will earn a client for life. His referal to others about your ability and willingness to to fix difficult problems will serve you well.

Bad choices for vendor or choice of gear or design before you were called to the job really have little bearing on the remedy, cost or solutionthat follows.

I think you will need to find a better location for the condensor to reject the heat. That is my unprofessional opinion. :D If that is not acceptable or possible, it is better to not attend the project (with explanation) because one's reputation on the line.

JMHO from the cheap seats.

[nike123]

I have to respectfully disagree. You can tinker with a bad job forever, but never achieve customer satisfaction. Customer satisfaction sets your reputation, regardless of who created the design mistakes that called you to the job. You need to identify the mistakes (unless there is just a bad part) and offer solutions. Tinkering on a bad job won't advance your lot.

I think one needs to provide the customer with value, regardless of bad choices made in the past. That also means not taking on obligations for a bad job that proceeded your visit. If you can correct the problems without excess cost, (for instance move the condensor to a better spot) you will earn a client for life. His referal to others about your ability and willingness to to fix difficult problems will serve you well.

Bad choices for vendor or choice of gear or design before you were called to the job really have little bearing on the remedy, cost or solutionthat follows.

I think you will need to find a better location for the condensor to reject the heat. That is my unprofessional opinion. :D If that is not acceptable or possible, it is better to not attend the project (with explanation) because one's reputation on the line.

JMHO from the cheap seats.

If equipment is not designed for job, then, no matter what you as serviceman do, it will newer perform that job satisfactory. If owner of equipment is aware of that fact in moment of purchase of equipment, and still, he buys that equipment in order to save himself some money, then it should be served as I described above because there is no alternative except change of equipment and buying new suitable for the task.

If you are going to use your pickup truck to move wast amount of load, from one point to another, only to save some money, instead buying some real truck of 20 ton load capacity suited for that job, then no one can help your small truck.