I'll see if I can answer your questions:
I have two Weil McLain Ultra 310 boilers and an Amtrol 100 gallon indirect fired water heater. The two Ultra 310s are used for both space heating water and are used to indirectly heat the domestic hot water in the Amtrol water heater.
Because of the fact that the boilers are used for both space heating and domestic hot water supply, the boiler outlet temperature sensor has to be in the water path both during space heating and domestic water heating.
This was the first problem I encountered as the heating contractor that installed the system originally had the outlet temperature sensor downstream of the heating system's main circulating pump. So, in the summer, when that pump was off, the boiler supply temperature sensor kept reading room temperature throughout the domestic water heating cycle. Thus, the Tecmar 265 controller was being told that the boilers were producing water of room temperature and kept ramping both of them up to 100% modulation to reach the target temperature. And so, they kept knocking themselves out trying to reach the target temperature (but never doing that since the @#$%ing sensor was in the wrong place.
So, we moved the boiler outlet sensor into the DHW loop, and that helped, but the boiler's own water temperature sensors detect the outlet temperature more quickly and accurately than the sensor strapped to the pipe that provides that temperature information to the Tecmar controller. So, in a couple of minutes, the boiler's temperature sensor is hitting 190 degrees F, but the strap-on sensor that the Tecmar controller is listening to is still only reading 170 deg. F, say. The result is that the Ultra still kicks itself out on soft lockout cuz of that 190 degree temperature, and when it cools down and fires up again, the Tekmar is telling it to modulate up to 100% again to reach the calculated target temperature of 180 degrees, say. And that kept happening over and over again, too.
So, the heating expert at Wolesley (formerly Westburne) came down and lowered the target temperature for domestic hot water generation from 185 deg. F down to 150 deg. F so that the boilers would achieve that target temperature and be controlled by the Tecmar. His thinking on this was that the water temperature inside the piping was higher than the strap on sensor was detecting, so even though the target temperature was lower, the actual temperature inside the heating coil in the Amtrol would still be at or above 170 deg. F. After doing that, the boilers would only knock themselves out about 5 or 6 times. But, typically, it was more common to see the DHW demand be satisfied after those 5 or 6 cycles than it was to see the boilers actually be modulated by the Tecmar.
So, now the gameplan is to install that temperature sensor in a well to get a faster and more accurate temperature measurement of the boiler water outlet temperature.
I fully expect the Ultra 310's have threaded outlets. However, somewhere between the boiler outlets and the piping that was installed in the boiler room they switched to grooved piping and RigidLok couplings. Where they did that, I don't know. And, as long as it doesn't leak, I don't care either. To me, grooved piping is as good or better than threaded piping.
I just reloaded Windows XP on my sister's computer, and I'm using it now. She doesn't have Adobe Acrobat reader, so I'll download that .PDF file and look at it once I'm back using my own computer.
So far as "sealing the probe" goes, we're planning to install a Victaulic #72 Outlet Coupling. Victaulic's "Outlet Coupling" is 2 3/4 inch wide, an that's 3/4 inch wider than a normal Victaulic coupling, or 7/8 inch wider than the 1 7/8 inch RigidLok couplings I have now. That outlet coupling holds the pipe ends 3/4 inches apart, which is enough to accomodate a well between the pipe ends.
The outlet coupling has a 1/2 inch female pipe thread, so if the sensor isn't close to the middle of the 2 1/2 inch diameter pipe, we can thread a short iron nipple and iron coupling into the port on the outlet coupling to move the location of the sensor 1/2 inch at a time.
And, cuz the Victaulic outlet coupling we're adding is 7/8 inches wider than the RigidLok standard coupling it's replacing, the 4 inch grooved nipple the RigidLok currently clamps around needs to be replaced with a 3 1/8 inch grooved nipple for the grooves and gaskets to all line up.
Does this makes sense to you? I hope so cuz we've already got the 3 1/8 inch grooved nipple and the Victaulic outlet coupling is on it's way. I also have two new EPDM rubber gaskets for the RigidLok coupling on the other end of that grooved nipple we're replacing.