Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Weil Mclain Ultra indirect domestic hot water fault

HortHort Member Posts: 5
edited June 25 in THE MAIN WALL
Recently I have noticed that during most calls for domestic indirect hot water heating that the return temperature is a few degrees hotter than the supply temperature and I get a lockout that automatically resets itself in time.
I have a post pump time set for 20 sec. but there does not seem to be a pre-pump time to set that may keep this from happening. This is DHW priority 1.
This is a recently new situation but has occurred during the heating season and now during warm weather shut down for house heat. Weil Mclain Ultra 105 series 3
Any thoughts?


  • HortHort Member Posts: 5
    edited June 25
    Max supply 160.
    mod on diff 2
    mod off diff 10
    Max rate 94%
    Min rate 20%
    Lockout usually occurs during first call for hot water in early morning
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!