WeilMcLain WM97+ - Temp Rise Too Quickly Lockout

[Indigo]

Hello - had a WM97+ installed this past fall along with its paired AquaLogic DHW indirect heater. Issue I am having is that when transitioning from making dhw to then heating the house (single zone) it is locking out with return water registering as hotter than supply water. This issue seems to mostly occur when it's not all that cold out and the water in the house rads is not all that hot. It will then lockout for a couple minutes and reset itself.

I have increased pre and post pump times on both the house zone and the dhw zone, but that does not seem to have made a difference.

Here's an example from one of the error logs, they are flagged as occurring in "Domestic Mode":

Temperatures:
Boiler Out 1: 118F
Boiler Out 2: 117F
Boiler In: 126F
Flue1: 126F
Flue2: 125F
Outdoor: 44F
CWH Tank Top: 150F
CWH Tank Bottom: 138F

Outputs:
Gas Valve: On
Boiler Circulator: Off
Circulator 1: On
Circ 2: Off
Circ 3: Off
Blower Signal: 25%
Alarm: Off

Inputs:
In1: On
In2: On
In3: Off
Manual Limit: Closed
Auto Limit: Closed
Low Water Cutoff: Closed
Blower Tach: 5340RPM
Flame Signal: 0

From what I've read this seems to be linked to a lack of water circulation - as far as I can tell the plumbing is ok, and matches what's in the manual, though it meanders a bit because the space is tight. Is this a matter of increasing zone 1 circulator speed? It's a 3 speed grundfos, which is in its middle position.

Will bring this to my contractor's attention, but am looking for any other thoughts on this / if anyone's seen this before.

Thanks!

 

[BadgerBoilerMN]

You should not trust on-line diagnostics of condensing boilers. Your contractor can access factory support and make certain the installation was within specs from start-up.

In particular you will want your installer to fill out the last two pages of the installation manual. Without this information factory support will be limited. Proper piping is the first step.

http://www.weil-mclain.com/en/assets/pdf/550142120_1113_WEB.pdf

 

[Sponsor]

 

[Indigo]

I totally get what you're saying -- and I'm absolutely not touching anything without the contractor's blessing. The pre and post pump times seemed unlikely to do any damage, and I reset them back to the way they were originally after concluding it was doing nothing.

What I'm looking for is any insight about what the problem could potentially be -- seems to be piping issues or lack of circulator flow are the likely culprits?

 

[Msgale]

I totally get what you're saying -- and I'm absolutely not touching anything without the contractor's blessing. The pre and post pump times seemed unlikely to do any damage, and I reset them back to the way they were originally after concluding it was doing nothing.

What I'm looking for is any insight about what the problem could potentially be -- seems to be piping issues or lack of circulator flow are the likely culprits?

the boiler intake(return) and output(supply) water temps after a run of indirect water heating WILL be hot, ( it will be the temp of the dom hot water.) much hotter than the space heating water temp, esp, as you say, on mild days. So when your boiler starts to draw in space heating water, it will naturally be colder than the water left over in the output pipe. Nothing wrong with this scenario.
why your boiler doesn't like it, that's another story(that i don't understand)