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Weil McLain ultra fault indirect Domestic hot water
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
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