Problem W/ Carrier Water Cooled Heat Pump

[Joelfu27]

I work at a hotel that uses mostly R22 Macquay Heat pumps in the rooms and any other space. The hotel is 8 years old and a few of the compressors have failed. The owner had the first 1/2 ton room MacQuay r22 heat pump that failed with a Carrier 410a 1 and 1/4 ton Heat pump.
Now our cooling tower is set at 70 degrees to the inlets of these units. We have had numerous problems with this carrier unit. I did not install the carrier, but did remove and install 5 other replacement 410a macquay heat pumps and haven't had any problems with them.
I know this is probably impossible w/out actually looking at the units yourselves, but my boss wants me to replace the carrier w/ one of our Macquay 410a units.
My question is ( finally) would the loop temp and pressure have an affect on this carrier unit. It has so many high and low pressure safeties, I think the problem is with the loop, not the unit, but I'm just a peon ( until it comes time to blame someone) I want to spend more time investigating why the unit keeps kicking out on these high pressure safeties, but he just wants it done. NOW.
Any advice. I'm kind of have my neck on the line even though I'm barely out of school and haven't had any type of apprenticeship, which my boss knows.

[Joelfu27]

Ok let me add a few things. The Carrier seems to run without problems in cooling, but kicks off after a few minutes in heating. The yesterday the refrigerant was reclaimed and weighed in to engineering specs, and the pressures vary greatly between heating and cooling. Any ideas? Its supply air is about 60 degrees Fahrenheit.

[tmm]

Joelfu27, If you have installed other Carrier 410A units which operate without a problem I would, as you suggest, be looking at the loop and in particular if this unit is actually getting the correct [design] volume of water.
Whilst this is quite a lot of work why don't you take one of the other units which operates well in another location and exchange it with the faulty unit. If the new unit shows the same problem you have proved to the boss that the loop requires investigation.