Gary in NJ
Member
I have an older boiler that is 3x oversized for my heat load and Dana suggested that I install a heat purging boiler economizer control on my aquastat to help with short cycling and gain some efficiency from the system. I purchased an Intellidyne 3250 HW+. Installing the controller took all of 10 minutes. It's as simple has connecting the unit to the hot and common for power, and then removing the wire in the aquastst that controls the burner and jumping to the controller. It took me as long to type this as it did to perform.
I do have a few questions regarding set-up.
Currently my aquastst is set for 187F. I'm quite sure I had it set to 180F, but I did have a service performed last winter and my guess is that the tech "up'd" the setting. Sure enough, the boiler shut down right at 187 (confirmed with the temperature gauge and an infer-red) and the temperature continued to climb to about 195. From an efficiency stand point I assume that I'd want the boiler to run hot (it's a WM Gold P-WGO-4 Series 3 and is safe to run to 210F). If I set the HLOLIM at 140F that would give me 55 degrees of purge to circulate before the HW+ releases the boiler to fire. I'm I thinking about this correctly?
Regarding Pre-Purge, my first check of the system was when the boiler had sat idle without firing for a few hours. The water temperature in the boiler was 140F. After the call for heat it took about 110 seconds for the circulator to engage and the boiler fired about 10 seconds after that. Was my pre-purge period 110 seconds, 10 seconds, or 120 seconds? I did a second test with the boiler still at 170 degrees. I cranked up the DHW to force a call. The circulator engaged about 60 seconds later and three minutes later I gave up waiting for the boiler to kick on as there was plenty off hot water in the system too meet the demand - the boiler never kicked on. So what exactly is pre-purge? What is the best test to determine the correct setting? Why the 50 second difference between the first and second test?
Regarding the DHW sensor, my hot water is set to deliver 140F. The directions for the DHW sensor say to install the sensor on the out flow pipe, which I did. The directions state....
"This parameter is used by the controller to set the low-limit temperature for the domestic hot water. When the domestic water temperature goes below this setting, “HEATING/LOLIM” will be displayed, and the controller will no longer attempt to achieve any savings and return control to the operating-control. To change this setting, plug the sensor into the appropriate jack to increase or decrease the value. The indicated value will be what is currently set in the controller (default = 120˚F / 49˚C). The range of adjustment is between 90˚F/32˚C and 180˚F/82˚C. Remove the sensor when the desired value is reached."
I ran my hot water at the sink for 5 minutes and confirmed that it was at 140F with the I/R. I then went to the outflow pipe and measured just 107F where the pipe leaves the tank. My guess is that the actual water tank is much lower in the enclosure, so by the time it exits the enclosure some heat has dissipated. So what would be the proper DLOLIM?
Thanks for any help.
I do have a few questions regarding set-up.
Currently my aquastst is set for 187F. I'm quite sure I had it set to 180F, but I did have a service performed last winter and my guess is that the tech "up'd" the setting. Sure enough, the boiler shut down right at 187 (confirmed with the temperature gauge and an infer-red) and the temperature continued to climb to about 195. From an efficiency stand point I assume that I'd want the boiler to run hot (it's a WM Gold P-WGO-4 Series 3 and is safe to run to 210F). If I set the HLOLIM at 140F that would give me 55 degrees of purge to circulate before the HW+ releases the boiler to fire. I'm I thinking about this correctly?
Regarding Pre-Purge, my first check of the system was when the boiler had sat idle without firing for a few hours. The water temperature in the boiler was 140F. After the call for heat it took about 110 seconds for the circulator to engage and the boiler fired about 10 seconds after that. Was my pre-purge period 110 seconds, 10 seconds, or 120 seconds? I did a second test with the boiler still at 170 degrees. I cranked up the DHW to force a call. The circulator engaged about 60 seconds later and three minutes later I gave up waiting for the boiler to kick on as there was plenty off hot water in the system too meet the demand - the boiler never kicked on. So what exactly is pre-purge? What is the best test to determine the correct setting? Why the 50 second difference between the first and second test?
Regarding the DHW sensor, my hot water is set to deliver 140F. The directions for the DHW sensor say to install the sensor on the out flow pipe, which I did. The directions state....
"This parameter is used by the controller to set the low-limit temperature for the domestic hot water. When the domestic water temperature goes below this setting, “HEATING/LOLIM” will be displayed, and the controller will no longer attempt to achieve any savings and return control to the operating-control. To change this setting, plug the sensor into the appropriate jack to increase or decrease the value. The indicated value will be what is currently set in the controller (default = 120˚F / 49˚C). The range of adjustment is between 90˚F/32˚C and 180˚F/82˚C. Remove the sensor when the desired value is reached."
I ran my hot water at the sink for 5 minutes and confirmed that it was at 140F with the I/R. I then went to the outflow pipe and measured just 107F where the pipe leaves the tank. My guess is that the actual water tank is much lower in the enclosure, so by the time it exits the enclosure some heat has dissipated. So what would be the proper DLOLIM?
Thanks for any help.
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