Handymaner
Member
Tweaking Delta T's
OK, I’m back. Work has been crazy; I’ve been forced to be away from home literally since the end of December. The boiler has been working GREAT, the reset curve seems to be really close as it just barely keeps up-which is the goal I guess? The usage has continued to be around 50-70% of last year, so I’m really happy with that.
The only trouble I’ve had is one of the baseboard radiators started leaking. I came home from work at about 2AM. I’ve been very in tune with what the boiler is doing since the install and after parking in the garage I instantly realized something was up, as the boiler sounded like it was at 100%-which it never is except for DHW and a 2AM that seemed odd. I went over and looked at the screen, and sure enough it was at 100%, the set point was calling for 130*, but the system temp was only at 80* and I realized I could hear make up water flowing! In the hazed thinking of panic (worried about a flood in the house) I noticed that only the upstairs loop was on. You can imagine the sleeping wife’s surprise as I ran the perimeter of the house turning on all the lights checking the baseboards looking for the flowing water! The upstairs was dry-so to the basement I went, thinking it may be from a portion of piping within the walls. No sign of leakage there either. Only then did it hit me that all the loops are pressurized through the return even if the zone valve is closed. So my dash continued through the sunroom and finally I found the leak in a semi-heated storage area off the sunroom. Thankfully I had the foresight to plumb in ball valves on both the return and supply side of the loops, so I could isolate the loop easily (without completely shutting down the boiler) for later repair. My wife said that she had heard water running prior to going to bed, so I know it had been leaking for 2 or 3 hours. I was later able to just bypass the bad baseboard.
I still need to tweak the delta t. I discovered that squeezing down the radiation loops actually lowered the delta t spread as read on the diagnostic screen. I guess that the pump on the primary loop must be recirculating more heated fluid when the radiation loops are slowed. I did squeeze down the valve in the primary loop as per Dana’s suggestion, and that method is able to raise the delta t considerably. With me being away I did not want to risk it being unmonitored, so I opened it back up.
Now that I will be home for a time I want to start tweaking again. I did have a chance to do some experiments but I haven’t found a reliable way to measure the temp of the pipes to find the delta t’s of my radiation loops. My IR gun is all over the map. I tried the tape suggestion, but it didn’t seem to help. I then grabbed my little desktop digital thermometer, the kind with the 5’wire with a probe on the end that you stick out the window to get indoor/outdoor temps. I tried to place the probe inside the pipe insulation but still can’t seem to get consistent results. My next attempt will be with the wife’s candy thermometer stuck inside the foam insulation. Any suggestions for an easy reliable way to measure the pipe temps?
OK, I’m back. Work has been crazy; I’ve been forced to be away from home literally since the end of December. The boiler has been working GREAT, the reset curve seems to be really close as it just barely keeps up-which is the goal I guess? The usage has continued to be around 50-70% of last year, so I’m really happy with that.
The only trouble I’ve had is one of the baseboard radiators started leaking. I came home from work at about 2AM. I’ve been very in tune with what the boiler is doing since the install and after parking in the garage I instantly realized something was up, as the boiler sounded like it was at 100%-which it never is except for DHW and a 2AM that seemed odd. I went over and looked at the screen, and sure enough it was at 100%, the set point was calling for 130*, but the system temp was only at 80* and I realized I could hear make up water flowing! In the hazed thinking of panic (worried about a flood in the house) I noticed that only the upstairs loop was on. You can imagine the sleeping wife’s surprise as I ran the perimeter of the house turning on all the lights checking the baseboards looking for the flowing water! The upstairs was dry-so to the basement I went, thinking it may be from a portion of piping within the walls. No sign of leakage there either. Only then did it hit me that all the loops are pressurized through the return even if the zone valve is closed. So my dash continued through the sunroom and finally I found the leak in a semi-heated storage area off the sunroom. Thankfully I had the foresight to plumb in ball valves on both the return and supply side of the loops, so I could isolate the loop easily (without completely shutting down the boiler) for later repair. My wife said that she had heard water running prior to going to bed, so I know it had been leaking for 2 or 3 hours. I was later able to just bypass the bad baseboard.
I still need to tweak the delta t. I discovered that squeezing down the radiation loops actually lowered the delta t spread as read on the diagnostic screen. I guess that the pump on the primary loop must be recirculating more heated fluid when the radiation loops are slowed. I did squeeze down the valve in the primary loop as per Dana’s suggestion, and that method is able to raise the delta t considerably. With me being away I did not want to risk it being unmonitored, so I opened it back up.
Now that I will be home for a time I want to start tweaking again. I did have a chance to do some experiments but I haven’t found a reliable way to measure the temp of the pipes to find the delta t’s of my radiation loops. My IR gun is all over the map. I tried the tape suggestion, but it didn’t seem to help. I then grabbed my little desktop digital thermometer, the kind with the 5’wire with a probe on the end that you stick out the window to get indoor/outdoor temps. I tried to place the probe inside the pipe insulation but still can’t seem to get consistent results. My next attempt will be with the wife’s candy thermometer stuck inside the foam insulation. Any suggestions for an easy reliable way to measure the pipe temps?