Modine Heater fan cycling on and off


  #1  
Old 12-11-22, 09:29 AM
T
Member
Thread Starter
Join Date: Dec 2022
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Modine Heater fan cycling on and off

Good morning - I have a couple of Modine Hydronic Heaters (Model # HC 47S01) and the fan on one of them is constantly cycling on and off despite the temperature in the room being 10-20 degrees higher than thermostat setting. The unit has a Honeywell Aquastat L6006C attached to the supply line. When I mirror the settings (both on the thermostat and the Aquastat from the working Modine the unit constantly cycles on and off. Fan stays off longer if I turn the thermostat on the Aquastat up to 200. The supply line on both units is around 165 degrees. I got tired of the noise from the fan as it is just outside my office so I disabled the Aquastat. Is that a problem? Would also appreciate any suggestions on what may be driving the issue. Thanks in advance.
 
  #2  
Old 12-11-22, 10:06 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 71,614
Received 3,321 Likes on 2,983 Posts
Welcome to the forums.

If the room temperature is over the set temperature..... that's a thermostat problem.
The aquastat just delays fan turn on until the coil is warm/hot.
 
  #3  
Old 12-11-22, 04:33 PM
T
Member
Thread Starter
Join Date: Dec 2022
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
thanks for the quick reply - it happens even when the system is turned off with the thermostat.
 
  #4  
Old 12-11-22, 09:42 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Location: United States
Posts: 2,674
Likes: 0
Received 56 Likes on 46 Posts
The aquastat usually starts and stops the fan on water temperature and the thermostat would be line voltage to stop electric from going to the fan motor or in series with the aquastat. It is possible the fan is getting flow when it should not be due to a bad flow check. Another option is there is actually no thermostat for that unit heater, and it runs when the water is hot enough.
Turn the thermostat you believe if for that heater all the way down, did it shut down. This will prove it is operating off the thermostat.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: