wm97+ indirect

cm406

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

190

190 is the factory preset target temp for domestic hot water, is there a problem?

Jean-David Beyer

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

lockout

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

lockout

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

Possibly

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

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

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.