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.

wm97+ indirect

Hi, I am a homeowner and have a wm97+ with indirect hot water tank. I am wondering where my target temp should be. It is currently on domestic status with target temp of 190 degrees. Thanks in advance, Chad


  • Boiler wrestler
    Boiler wrestler Member Posts: 43

    190 is the factory preset target temp for domestic hot water, is there a problem?
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    It is currently on domestic status with target temp of 190 degrees.

    I believe that unit used the W-M U-control. If so, it has three reset curves. One for the priority 1 input, one for the priority 2 input, and one for the priority 3 input. Priority 1 has the most priority, and is generally used for the indirect. Factory default for that is 190F. I have very low hot water demand and I lowered it to 175F to possibly get a little more condensing, but normally leaving it at 190F is the best balance between speed of recovery and fuel usage.

    For my system, I use priority 2 for my in-slab radiant zone that uses the most heat, and priority 3 for my baseboard zone that uses the least heat. I have one reset curve for priority 2 and a somewhat hotter one for priority 3.
  • cm406
    cm406 Member Posts: 3

    It keeps locking me out when it heats the glycol for my garage floor. The target temp changes from 190 to 146 degrees then it says over temp lockout. I manually reset it and it will work for awhile, then randomly it will lock me out.
  • Boiler wrestler
    Boiler wrestler Member Posts: 43

    What is the reason for the lock out?  If it is not liking the temps you can increase the pre pump time on the space heating circulator to lower the temp as sometimes it has problems shifting from high temp to low temp.
  • Gordy
    Gordy Member Posts: 9,537

    The boiler flow rAte across the HX is not sufficient. Is this happening in a scenario where domestic hot water has just finished a call then the glycol loop calls for heat? I assume the garage loop has a heat exchanger, or is the whole system glycol based?
  • cm406
    cm406 Member Posts: 3
    got it

    Thanks for the responses. I did some reading in my manual & figured out that it was set on custom @190 when I needed slab on grade radiant which is 120 degrees. Everything is working great now.
  • Terry O
    Terry O Member Posts: 67
    edited December 2013
    You are partly correct...

    The 97+ does use a U-control.... it however is not the same as used on the Ultra series. The 97+ control only has 2 temp priorities... with zoning capabilities for 3 zone.

    I would lower the 190f temp. I usually program DHW boiler temp at 170F.
    Terry O
This discussion has been closed.