old evap coil

[JAYSONREF]

I have an old McQuay evap coil with no numbers on it. It has two fans and the coil is 22"x44"x4" is there any to figure out the capicaty of this coil? Ant help would be great

[MeÐiC]

What is the evap for, cooler or freezer? Box size?

[JAYSONREF]

its a cooler on a farm and it has been patched together. we just took over this account and the history i got is that they keep loosing compressors every 2-3 years. we just replaced the compressor and found txvs are way over sized. we want to install the correct valves but dont no what size the coils are. there are 2 coils in the cooler. the unit is running r22 which mekes think the valves were changed cause the coils are old

[mseng]

If you suspect the TXV’s are over sized and you can not find out the BTU’s of the coil without doing a tube/fin calculation. You need to check the superheat and if you cannot throttle it down then put in a smaller TXV and check the superheat again.

[CRussell1975]

Call McQuay, give them the dimensions, number of rows, fins per inch, etc, and refrigerant you are using and they should be able to tell you. They manufactured it after all.

[bunny]

While not always a perfect indication of evaporator capacity, you can take the compressor model and find the performance chart for it...find its Btu capacity at the design condition. The evaporator capacity should be close (+/- a few %).

[icemeister]

My Dad had a rule of thumb for the capacity of low profile evaporator coils:

• 1 Fan = 1/2 HP
• 2 Fans = 1 HP
• 3 Fans = 1.5 HP
• 4 Fans = 2 HP