25
c l i m a t e m a s t e r.c o m
Trilogy
®
Variable
(VE) Series IOM - 60Hz HFC-410A
R e v i s i o n D a t e : 2 2 D e c e m b e r, 2 0 2 1
Water Quality Standards (Cont.)
OHM meter
Measuring Earth Ground Resistance
0.02
�
Building
Ground Rod
Well Casing
Measure the earth ground bond using an Ohm meter between the building's ground rod and the steel well casing.
The resistance measured should be zero Ohms. The NEC allows a resistance to ground up to 20 Ohms. Any
resistance above zero, indicates a poor earth ground which may be the result of a hot neutral line or that
conduc
�
ve water is present. Both of these may lead to electrolysis and corrosion of the heat pump piping. A check
for both should be performed and resolved.
Note if the well casing is plas
�
c, a conduc
�
ve path can be achieved by inser
�
ng a #6 AWG bare copper wire into the
well water. Remove the temporary conductor when
fi
nished.
Measuring Electrolysis Voltage and Current
Measure the electrolysis voltage using a volt meter between the heat pump ground and a #14 AWG solid copper
wire electrode inserted into the water using a Pete's style access port.
The HP must be opera
�
ng and the water stream
fl
owing.
The voltage measured should be less than 300mV (0.300 V). If higher than 500mV electrolysis will occur and
corrosion will result.
If voltage is measured, the cause is a high resistance earth ground or current on the neutral conductor. Remedial
measures should be performed.
Measure the current
fl
owing through the piping system by using an amp clamp probe on the water-in line. The HP
must be opera
�
ng and the water stream
fl
owing.
There should be zero amps measured. If current is present, there is leakage current to the plumbing system and it
must be rec
�fi
ed to prevent pipe corrosion.
Volt Meter
300mV
Heat Pump
Wire Electrode inserted into port for
Voltage measurement
Pete's Port
HP Piping
Amp Sensor to VOM for Current
Water-in
Water-out