Lochinvar HS 50 Series 100, User'S Information Manual

16

temperature control opening. It is not recommended to 
install the temperature probe or sensor in the bottom or 
the top of the tank. It is typical to install in the mid to lower 
portion of the tank.

Do not install the temperature sensor near the cold water 
supply connection to the storage tank to prevent short cycling.  

The list below represents some of the most critical installation 
requirements that, when overlooked, often result in operational 
problems, down time and needless parts replacement. This is 
not a complete list. Before performing any troubleshooting 
procedures use the list below to check for installation errors. 
Costs to correct installation errors are not covered under the 
limited warranty. Ensure all installation requirements and 
instructions in this manual have been followed.

LOCATION

1. 

Ensure the HPWH is located where there is a adequate supply 
of source water for optimal performance.

2.  Ensure required clearances are maintained and there is 

access for servicing. See Clearances on page 9.

WATER PIPING

3.  Ensure the outlet (supply) and inlet (return) water piping 

connected to the HPWH are not less than the connection 
size on the unit. See Table 1 on page 7.

4.  Ensure swing-type check valves (not spring-loaded types) 

are installed on outlet lines of all heat pumps plumbed in 
parallel to prevent hot water short-circuiting.

5.  When the HPWH is connected to a storage tank ensure the 

storage tank is equipped with a properly rated and sized 
Temperature and Pressure (T&P) relief valve. Refer to the 
storage tank manufacturer’s instructions for T&P valve sizing 
and installation requirements. 

Note: 

 This is a critical installation requirement that must not 

be overlooked. Call the toll free technical support phone 
number at the back of this manual for further assistance.

MULTIPLE TANK PRE HEAT CONFIGURATION

When water temperatures above 150°F (66°C) are required the 
HPWH and storage tank are piped in series (upstream) with a 
backup water heater. See Water Temperature on page 8. The 
backup water heater will raise the temperature of the 
preheated water to the fi nal system temperature required. 
Figure 8 shows a typical preheat piping confi guration.

STANDARD TANK THERMOSTAT

Standard tank thermostats (Aquastat) already installed in the 
storage tank may be used instead of the factory supplied 
Digital Tank Thermostat if desired. Ensure the standard tank 
thermostat is installed the lower third of the tank. Wire the 
existing tank thermostat to the HPWH terminal strip.

TEMPERATURE SENSOR INSTALLATION

The HPWH unit is shipped from the factory with a Digital Tank 
Thermostat that includes a Temperature Sensor:

1. Secure 

the 

Temperature 

Sensor inside a Sensor or Thermal 

Well .

2.  Install the sensor well in the storage tank’s designated 

FIGURE 7

FIGURE 8

FIGURE 9

INSTALLATION CHECKLIST