Rheem RESG75-40BP, Use & Care Manual

26

Use and Care of the System

See Figures 16, 17, 18 & 19 for the location 

of the specific components numbered below.

1)   Solar Collector(s) (Rheem RS Series): 

Absorbs the sun’s heat energy and 

transfers this heat to the HTF circulating 

through the collector.  (Provided)

2)   Collector Sensor (Stecca PT1000):  

Wired to the system controller.  

Works in conjunction with the tank 

sensor to automatically turn your 

circulating pump on and off at preset 

temperature differentials.  (Provided)

3)   Tank Sensor (Stecca PT1000):  Wired to the 

system controller.  Works in conjunction 

with the collector sensor to automatically 

turn your circulating pump on and off at 

preset temperature differentials.  (Provided)

4)   Differential Thermostat (Stecca 

Controller RHTR0301U):  Known as 

the controller.  Automatically turns the 

circulating pump on and off when there 

is sufficient heat to be gained from the 

solar operation.  The controller also may 

be set to limit high temperature build up 

in the solar storage tank.  (Provided)

5)   Circulating Pump (Grundfos UPS15-

58FC or equivalent):  Circulates the HTF 

through the collector loop.  (Provided)

6)   Isolation / Drain Valve (Unique 50613 or 

equivalent):  When closed in conjunction 

with No. 7 will isolate the circulation 

pump for repair or replacement.  Used 

to charge the collector loop with glycol, 

purge air from the loop and drain the 

heat exchange fluid.  (Provided)

7)   Isolation / Drain Valve (Unique 50613 or 

equivalent):  When closed in conjunction 

with No. 6 it will isolate the circulation 

pump for repair or replacement. Used 

to charge the collector loop with glycol, 

purge air from the loop and drain the 

heat exchange fluid.  (Provided)

8)   Isolation Ball Valve (Cash Acme 

20800-204 or equivalent):  Used in 

conjunction with component No. 7 to 

isolate the solar collector loop from 

the solar storage tank.  (Provided)

9)   Pressure Relief Valve (Cash Acme 09564-

0125 or equivalent):  Will release glycol 

loop HTF at 75 PSI.  If this valve opens 

and the HTF fluid is expelled contact your 

contractor immediately.  This valve also can 

be opened to drain the HTF from the charge 

glycol loop for replacement.  (Provided)

System Component Parts 

pump is running and the control indictor 

light "Solar" #1 is on after 6:00 p.m., check 

both sensors to see that they calibrate to 

10K ohm resistance at 77°F. If you find a 

defective sensor replace it immediately. 

Note that in a two tank system nighttime 

heat loss will be harder to detect, especially 

if you are operating in the solar preheat 

mode. Check the line thermometers (No. 

22) in the collector loop piping to detect 

night thermosiphoning.

•  If the weather is poor and your gas solar 

storage tank is not heating water, the pilot 

may have to be lit.  Refer to the storage 

tank manual for lighting instructions and 

diagnostic procedures.

        Never remove the Burner Access Door 

unless absolutely necessary.  This should 

only be done by a qualified service 

technician.  A new burner access door 

gasket must be installed on any burner 

access door that has been removed.

       If the pilot will not stay lit or you still 

do not have hot water after one hour, the 

thermocouple or thermostatic gas valve 

may be defective.  Contact your installation 

contractor for service.

Maintenance and Troubleshooting continued