Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

HONEYWELL ODR Boiler Control - Best Settings???

abro42 Member Posts: 12
hi and hell:

Great forum for help and answers. Now the following:

I am using a Buderus G115 boiler w/ only 2 zones. Recently installed ODR module from Honeywell 50022037-002 w/ EnviraCOM connected to Honeywell Aquastat L7422U. The ODR model has a -5/4 reset curve. Meaning for every 4 deg boiler water reduction, you gain 1 % boiler efficiency. Is this a good rest curve for use? Is the HONEYWELL ODR too old and needs to be updated with a more modern digital ODR??

I noticed water drips from the outside exhaust pipe just before exit thru the wall. This means condensation, not good. Boiler TEMP at the boiler output shows a low of 110-120, not good. When a request for heat occurs it will fire and stop at about 150 deg. This is inline w/ reset curve based on a 30 deg outside temp. My HL is 180 deg and boiler min is set at 130 (think it should be higher). All defaults are being used at the ODR.

Very little boiler operation as we have installed plates, 2 in radiant barrier, and R19 in the bays so its a staple up radiant floor system. I use the TEKMAR 561 TSATs and floor sensor show 75 deg. Room temp is 70 deg. Very comfortable so I think all is OK except for condensation

Again.....is my ODR curve adequate from the HONEYWELL ODR unit?? Condensation seems very likely w/ this ODR and default settings. Any recommendations for settings? Anybody using the HONEYWELL ODR??

Thx from Vermont, stay safe.


  • SuperTech
    SuperTech Member Posts: 2,205
    I have the same ODR module for my Peerless boiler and Indirect water heater.  Its a great thing to combine with the L7224U aquastat for a partial reset on a cast iron boiler.  

    That being said, it has to be set up correctly and combined with good near boiler piping to avoid condensation. You also have to make sure the boiler is adequately sized for the load on it. If you have an oversized boiler, ODR will make it a worse problem by creating shorter cycles that don't allow the flue temperature to get hot enough to avoid condensate formation.  

    I would check your settings. What are you using for design temperature? You want to make sure that your boiler return water temperature is at least 135-145 degrees by the time the burner shuts off. Stack temperature should also be at least 350 degrees depending on the fuel. Let me know your settings and I will help as much as possible.  
    Also pictures of the boiler and its piping would be helpful as well.