Hayward OmniPL, cooldown mode for heater and bypass valve actuation

ajw22 said:

Check that you don't have the IN and OUT reversed on the heater.

Click to expand...

That I am sure about. The non-collapsed is the IN, there is a small black arrow molded into the inlet pointing towards the header. What I *think* happened is the heater was turned off manually using the OmniPL control panel and the valve closed leaving the hot water with nowhere to go. But until I replace the pipe, I cannot test - won't fire it up in the state the plumbing is in. Hope to replace it tonight.

I was just hoping someone here that has extensive experience with Hayward's Omnilogic system (OmniPL in my case) knows how cooldown mode works specifically.

-Tom

I will look at the inlet pipe again - but I did not see any deformation yesterday when I found the collapsed outlet pipe.

-Tom

Pretty sure that is a shadow artifact.

What I need to know is how Hayward cooldown mode works - does the low voltage relay get opened (turning off heater) then the cooldown time elapses before the actuator on the valve is demanded closed. Or does the relay get opened and the actuator close the valve at the same time.

-Tom

The configuration screen, when gas type was selected, prompted for which low voltage relay and asked if a valve was installed for the heater, I selected the appropriate valve port where the actuator was plugged in. I do know that the controller is indeed turning the valve on/off with call for heat. I have watched it when I manually flip the display to heat on and heat off. So the manual does not seem to match the config screens.

I tested that to get the correct cam settings while I was waiting on the plumbers to get the gas line installed. I did NOT test the cooldown function. I will be...

If cooldown does NOT control the valve appropriately - not sure what to do then. Other than adjusting the actuator cams to always have some amount of water going thru the heater. Which is not really my preference.

Here is the XML file data (config data that can be saved to disk) for the heater, showing valve operations and cooldown enabled (bolded/highlighted in RED:

-<Heater>
<System-Id>20</System-Id>
<Shared-Type>BOW_NO_EQUIPMENT_SHARED</Shared-Type>
<Enabled>no</Enabled>
<Current-Set-Point>86</Current-Set-Point>
<CoolingCurrentSetPoint>70</CoolingCurrentSetPoint>
<Max-Water-Temp>104</Max-Water-Temp>
<Min-Settable-Water-Temp>65</Min-Settable-Water-Temp>
<Max-Settable-Water-Temp>104</Max-Settable-Water-Temp>
<Cooldown-Enabled>yes</Cooldown-Enabled>
<Extend-Enabled>yes</Extend-Enabled>
<Boost-Time-Interval>300</Boost-Time-Interval>
<Heater-Become-Valid-Timeout>900</Heater-Become-Valid-Timeout>
-<Operation>
PEO_INIT
-<Action>
<Action-Function>ACT_FNC_HEATER_STARTUP</Action-Function>
<Action-Data1>0</Action-Data1>
<Action-Data2>0</Action-Data2>
<Action-Data3>0</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_TEAR_DOWN
-<Action>
<Action-Function>ACT_FNC_HEATER_TEARDOWN</Action-Function>
<Action-Data1>0</Action-Data1>
<Action-Data2>0</Action-Data2>
<Action-Data3>0</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_HEATER_EQUIPMENT
-<Heater-Equipment>
<System-Id>21</System-Id>
<Name>Gas</Name>
<Type>PET_HEATER</Type>
<Heater-Type>HTR_GAS</Heater-Type>
<Enabled>yes</Enabled>
<Priority>HTR_PRIORITY_1</Priority>
<Run-For-Priority>HTR_MAINTAINS_PRIORITY_FOR_AS_LONG_AS_VALID</Run-For-Priority>
<Allow-Low-Speed-Operation>yes</Allow-Low-Speed-Operation>
<Min-Speed-For-Operation>50</Min-Speed-For-Operation>
<Requires-Priming>no</Requires-Priming>
<Min-Priming-Interval>180</Min-Priming-Interval>
<Temp-Difference-Initial>8</Temp-Difference-Initial>
<Temp-Difference-Running>2</Temp-Difference-Running>
<Sensor-System-Id>-1</Sensor-System-Id>
<Shared-Equipment-System-ID>-1</Shared-Equipment-System-ID>
-<Operation>
PEO_OPEN_VALVE
-<Action>
<Action-Function>ACT_FNC_HW_ACTIVATE_VALVE</Action-Function>
<Action-Data1>12</Action-Data1>
<Action-Data2>1</Action-Data2>
<Action-Data3>1</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_CLOSE_VALVE
-<Action>
<Action-Function>ACT_FNC_HW_ACTIVATE_VALVE</Action-Function>
<Action-Data1>12</Action-Data1>
<Action-Data2>1</Action-Data2>
<Action-Data3>0</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_GET_TIME_VALVE_LAST_TURNED
-<Action>
<Action-Function>ACT_FNC_HW_SEC_SINCE_VALVES_LAST_TURNED</Action-Function>
<Action-Data1>0</Action-Data1>
<Action-Data2>0</Action-Data2>
<Action-Data3>0</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_GET_VALUE
-<Action>
<Action-Function>ACT_FNC_GET_VA_RELAY</Action-Function>
<Action-Data1>12</Action-Data1>
<Action-Data2>1</Action-Data2>
<Action-Data3>0</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_TURN_ON
-<Action>
<Action-Function>ACT_FNC_TURN_ON_LV_RELAY</Action-Function>
<Action-Data1>2</Action-Data1>
<Action-Data2>1</Action-Data2>
<Action-Data3>1</Action-Data3>
</Action>
</Operation>
-<Operation>
PEO_TURN_OFF
-<Action>
<Action-Function>ACT_FNC_TURN_ON_LV_RELAY</Action-Function>
<Action-Data1>2</Action-Data1>
<Action-Data2>1</Action-Data2>
<Action-Data3>0</Action-Data3>
</Action>
</Operation>
</Heater-Equipment>
</Operation>
</Heater>

-Tom

I replaced the collapsed SCH40 pipe, and tested the heater out today. The OmniPL does turn the heater off and closes the valve at the same time - preventing cooldown flow. That would indeed cause the water in the heat exchanger to super-heat, from the residual heat in the heater and cause the overheated exit pipe.

I have opened a case with Hayward via their online form - to see if this is functioning "as designed", or not. If "as designed", I asked if they would consider a future enhancement to the code to not close the valve until the cooldown time has expired.

For now - I will adjust the cams in the Hayward actuator to allow some flow thru the heater at all times, so when it is turned off, there will be water still flowing to allow the heat exchanger to cool appropriately. Kinda defeats the purpose of a heater bypass valve...

-Tom