Prestige Solo 110

otremba2

Owner of a Prestige Solo 110 Boiler/Indirect DHW system.

DHW system stopped functioning properly the other day [no domestic hot water]. Checked DHW tank temperature through Solo 110 control interface and it was showing a DHW Temp of 240F [i.e. Aquastat on LAARS 48Gallon indirect tank not functioning properly].

For whatever reason [unknown to me] the DHW supply line from the storage tank has pipe mount temperature sensor with leads not connected into the Solo 110 boiler Main Control Board. Upon swapping the aquastat leads with the pipe mount temp sensor leads @ the boiler main control board, the Solo 110 control interface was returning a more realistic DHW Temp of 72F [i.e. space temp].

With the boiler receiving correct storage tank temp, boiler was still not initiating a call for DHW heating [i.e. circulator not being energized and boiler ignition/heating sequence not being initiated]. Confirmed Parameters of 140F for DHW temp and "01" for Domestic Hot water Setup. Circulator is operational [tested by hardwiring direct into 120V circuit].

Upon further review, when measuring voltage across DHW circulator circuit [i.e. blocks 4/5 @120V terminal strip], noted 50V in lieu of 120V [during what should be a call for DHW heating sequence].

Few questions:
1) Has anyone had a similar experience and willing to share insight/solution?
2) I suspect a faulty control board but are there any additional test/checks I could make? Plan on testing the voltage across the main control board DHW power blocks [i.e. blocks X1-5 & X1-3] in addition to test I performed across the 120V terminal strip.
3) In lieu of spending $600 dollars for new main control board, could someone recommend an alternate (less expensive solution)...I.e. operation of circulator/boiler ignition sequence via aquastat in lieu of through main control board...

Thanks for the help!

Zman

There are two ways to set up the DHW call on that boiler. It can either read the sensor which is usually installed in the tank's sensor well or it can work off the tanks aquastat (switch). You need to have the correct setting in the boiler to tell it which signal you are using.
There are also at least a dozen settings that if set incorrectly will cause it to not function correctly. https://www.triangletube.com/getmedia/773a8c23-9f26-4a7e-ba4a-37d210d98fca/PS-Control-Supplement-5-MCBA.pdf?ext=.pdf
The 50 volts is a head scratcher. The meter might just be picking up some ghost current.

otremba2

Appreciate the input Zman. Ended up switching the DHW operation off of the NTC instead of the Aquastat and she's humming according to plan now. Any issues or concerns running off of the NTC instead of the Aquastat?

otremba2

Oh btw, all the DHW setting were according to the manufacturer defaults. So ruled that out as an issue but that supplement you provided gave me the info need to switch over to NTC.

Zman

I prefer the sensor to the aquastat. It gives you more control like on/off differential.

kolyan

I just replaced to sensor, definitely better option due to controls.
legionella function also only works with sensor.