PATH freewatt HDJ, Installation, Operation & Maintenance Manual, Page: 51 / 68

51
Table 16-2
Alarms Codes for Combined Heat and Power LED on
freewatt Control Module
Combined Heat Power
LED Status
Condition
Rapid Flash
(~5 per second)
MCHP operation suspended
on detection of high coolant
temperature
Steady ON Normal MCHP Operation
16.5 MCHP Suspended Mode
MCHP operation will be suspended if there is detection of
high coolant temperature, indicated by rapidly fl ashing
Combined Heat and Power LED. MCHP Suspend Mode
prevents MCHP unit from cycling in overheat situation
in which it cannot run. Condition may be due to boiler
temperature set higher than recommended, improperly
commissioned system, or high aquastat setting on indirect
hot water tank. Perform following tasks if suspend
condition is encountered.
Check boiler parameters • . Hydronic freewatt system
has maximum recommended design water temperature
of 160° F. Suspend mode will occur and effect overall
MCHP runtime and power generation, if boiler water
temperature is higher than 160° F.
Check aquastat on indirect water tank is set no
•
higher than 125° F. MCHP may not run while boiler
is satisfying indirect hot water tank, if aquastat must be
set higher for hot water recovery.
Ensure fl ow is presen
• t in coolant loop and hydronic
loop (check for working pumps).
Ensure system is properly commissioned
• per
Hydronic Commissioning Procedure.
16 - TROUBLESHOOTING
16.6 Control Board LED Interpretation
Observe green LEDs on control board by removing •
cover of freewatt Control Module.
Control Board LEDs are valid only in Combined Heat
•
and Power Mode (CHP Mode switch “ON”). They are not
used when system is in Bypass Mode (CHP Mode switch
“OFF”).
Do not use Control Board LEDs as indicator of system
•
status when in Bypass Mode.
Table 16-3
Controller Board LED’s indicate:
LED ON LED OFF
Z1 Zone 1 circulator ON Zone 1 circulator OFF
Z2 Zone 2 circulator ON Zone 2 circulator OFF
Z3 Zone 3 circulator ON Zone 3 circulator OFF
Z4 Zone 4 circulator ON Zone 4 circulator OFF
Z5 Zone 5 circulator ON Zone 5 circulator OFF
Z6 Zone 6 circulator ON Zone 6 circulator OFF
MCHP ENB MCHP enabled MCHP disabled
X1X2
Relay XX end switch
relay closed
Relay XX end switch
relay open
MyEND
freewatt Control
Module closed either
DHW or CH input to
boiler, requesting
boiler operation
freewatt Control
Module not requesting
boiler operation
PUMP1
24 VDC coolant pump
in HI Module energized
24 VDC coolant pump
not energized
PUMP2
120 VAC Hydronic
circulator connected to
HI Module energized
through external relay
switch
120 VAC Hydronic
circulator not
energized
PUMP3 Not used Not used
NOTE: One or more zone circulators may be activated
without specifi c call for heat by room thermostats or DHW
aquastat consequence of control logic anticipating heat de-
mand and attempting to maximize MCHP run time.