20.3 Troubleshooting Domestic Hot Water
TROUBLESHOOTING A “NO DHW” CALL:
A “DHW PROD ERR” message will appear on the LCD screen of the R2107 control with regard to domestic hot water
production.
DHW ERR - when the tank temperature drops to the low limit (9°F below the set point), the R2107 goes into DHW
priority mode.
During DHW priority, the R2107 raises the boiler water temperature to it’s high limit, interrupts power to the space
heating circuit {terminals 61(N) & 63 (H)} and energizes the DHW pump circuit {terminals 24 (N) & 25 (H)}. The pump
circuit symbol
is displayed on the LCD screen.
In DHW priority, if the R2107 does not sense a rise in DHW temperature in 30 minutes, it will display a DHW PROD
ERR message.
At this point, the control will go back to space heating mode and lock out the DHW to avoid freezing the building. This
message is general in nature and the R2107 control is essentially telling you, “I tried to make domestic hot water but
nothing happened”.
IN MOST CASES THE PROBLEM IS NOT WITH THE R2107 CONTROL. To rule out the R2107, turn power off to the
R2107 to reset.
The R2107 will again try to make DHW. Check terminals 24 & 25 for 120V. If power is present and boiler fires the R2107
is o.k.
Check the following:
1 - bad circulator
2 - stuck flow check
3 - piping is air bound
4 - closed valve
Logamatic 2107 controls - We reserve the right to make any changes due to technical modifications.
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20
Troubleshooting
