Frozen PEX or air locked...or something more sinister?
#1
02-24-15, 08:01 AM
Frozen PEX or air locked...or something more sinister?
Hello I have a 6 zone heating system using a Lochinvar Knight KBN151 setup.
Each zone has a Grundfos pump on it.
About 5 days ago Zone 1 stopped heating. I checked the thermostat for the zone, it was "on" and set to 70. The room was showing 64. I went to the basement and the Argo LED for that zone and thermostat was lit green. So I figured the wiring was ok. I then swapped the relay for that zone with one from a working zone and I have ruled out the relay.
I feel the feed and the return pex pipes for this zone and they are cold. The Grundfos pump when on feels hot and seems to be working (it sounds a bit noisy though) I made sure the PSI in the system is at 15 and then proceed to go to the radiator bleeders on this zone, there are 6 radiators in this zone, I was able to get water out of each bleeder.
Any ideas or thoughts are appreciated.
Thanks!
Each zone has a Grundfos pump on it.
About 5 days ago Zone 1 stopped heating. I checked the thermostat for the zone, it was "on" and set to 70. The room was showing 64. I went to the basement and the Argo LED for that zone and thermostat was lit green. So I figured the wiring was ok. I then swapped the relay for that zone with one from a working zone and I have ruled out the relay.
I feel the feed and the return pex pipes for this zone and they are cold. The Grundfos pump when on feels hot and seems to be working (it sounds a bit noisy though) I made sure the PSI in the system is at 15 and then proceed to go to the radiator bleeders on this zone, there are 6 radiators in this zone, I was able to get water out of each bleeder.
Any ideas or thoughts are appreciated.
Thanks!
#2
02-24-15, 03:19 PM
Hi Doc,
Just because water came out of the bleeders is not really an indication that there is not a frozen spot at some point in between a couple of the rads.
Water pressure can come up from either side of the loop and out the bleeder.
How much of the interconnecting pex can you actually see?
proceed to go to the radiator bleeders on this zone, there are 6 radiators in this zone, I was able to get water out of each bleeder.
Water pressure can come up from either side of the loop and out the bleeder.
How much of the interconnecting pex can you actually see?
#3
02-24-15, 04:30 PM
For the sake of argument, let's assume the pipe is frozen. Possibly, a section of pipe or one of the connections has broken because of the freezing. When it does thaw, best to be home to make sure there isn't a big leak. If you can't be home, and even if you can, best to shut the manual valve between the automatic fill valve and the city water supply.
