Chapter 8 – Maintenance
TestEquity 1016C-1027C Temperature Chamber
Page 8-3
How to inspect the refrigeration machinery compartment.
!
WARNING:
Wear safety goggles when inspecting the machinery compartment to protect
against a refrigerant line which could break.
1.
Turn the Main Disconnect Switch OFF.
2.
Remove the side and rear panels.
3.
Inspect for signs of refrigeration tubing abrasion.
4.
Inspect for oil around refrigeration valves, fittings and joints. This may be a sign of leaks.
5.
Inspect for loose hardware and tighten as required.
6.
Inspect for signs of insect or rodent infestation. Yes, it does happen!
How to check the low-stage refrigerant charge.
The low-stage refrigerant charge is checked by observing the “standby pressure” (also known as
static or balance pressure).
1.
Make sure the chamber has been off for at least 8 hours.
2.
Locate the two low-stage gauges marked R-508B on the left side of the rear of the chamber.
3.
The two gauges have different scales. However, they should read the same value of pressure.
This indicates that the system is equalized and an accurate reading can be taken.
4.
Both R-508B gauges should read approximately 120 PSIG.
5.
If the pressure is low, this indicates that there is probably a leak.
6.
If one gauge is low and the other is high, then the system is not equalized yet and an accurate
reading cannot be made. Wait until both gauges read the same pressure.
NOTE:
If the low-stage has been evacuated and recharged after a repair, the standby pressure
should be rechecked after 24 hours to make sure it is 120 PSIG. This is because the R-508B
refrigerant mixes with the oil in the compressor, causing a lower standby pressure. Do not
mistake this initial loss of pressure with a leak. After verifying that there is no leak, you may
need to top-off the charge if the pressure is too low. This note only applies to systems that have
been evacuated and recharged.
