zerol ice reducing system capacity

zepfan

I got a call on a one and a half ton trane split system heat pump, that may be undersized for the space and that was the reason for the call.while I was there I recorded the following readings:

suction-85 discharge-190 sh-20 sc-2 indoor wet bulb-71 outdoor dry bulb-87 indoor dry bulb-81, delta t across evaporator-14 delta t across the condenser- 8

the thing that seemed not right with this system was the low condenser split (condenser coil was clean and the head pressure is normal),and that it took nearly 30 minutes of run time for the  superheat to come down and the evaporator to start to produce condensation.

when the system was install someone put zerol ice in the system, and I was wondering if anyone has had experience with this, and was also wondering if this was what took the system so long for the superheat to come down. i have never used this product, and am thinking that this may be effecting this system's performance or am I overlooking something here

Techman

zerol ice

That zerol stuff is for the oil and should not affect the Freon pressurers , by very much. With an 87* ambient ,I think the hi side should be closer to 250psig . What is the vertical separation between cond/evap ? That SH was at the comp? 10-12* of SH for the evap and the rest thru the suction line.!

zepfan

thanks

thanks for the response. there is next to no separation between the condenser and the evaporator. the condenser sits at ground level, and the evaporator is in the crawl space. about 15' of line set, no insulation missing off the suction line. the longer the system runs, the lower the superheat gets after about an hour and a half it's gets to around 10 degrees.     

Techman

system

Got a SG/MI ? Can you verify a full liquid line at the TXV ? What was the indoor temp after the 1 1/2 hr of running ?

Spence

Capacity

At an ambient of 87 degrees and an IDB of 81, you have a huge load on the system, leading to longer run time and high SH. Also note that your latent load is massive (71 degrees WB), so it is extremely difficult for your machine to neutralize that load with only a 14 degree TD. With a 15' lineset, your factory refrigerant charge should be dead on; perhaps off a few ounces if you have a large evaporator. It sounds as if an airflow calculation is in order.