error code explanation Tekmar 354 mixing control

rgraham

The system has been working fine for years. The furnace is working normally.
I have no heat in the house. Thermostats are turned up. Supply side pipe temp is up where it should be. Return side pipe temp is very low. No changes to the system recently.
I ran a test sequence. The heat demand and WWSD are both solid red after test.

What should I check next?

neilc

circulator(s) and or zone valves,
and that's a question also,
which do you have?
you're not distributing the boiler heat to the building, why?

neilc

and also,
what's controlling the circ and or valves?
maybe post one "big picture" picture of boiler circ(s) and valves(?)

STEVEusaPA

Do you still have the manual? You should start checking/measuring the sensors, and the output voltages, following the install manual.
I assume the circulators aren't running.
What error messages were you getting on the display as you scrolled thru them during the test procedure?
I'm leaning towards a sensor issue.

rgraham

this is the System Board

rgraham

this is the model 354 during the test sequence. It is hard to see, but the Heat Demand LED is lit red along with the Test LED

rgraham

this is the mixing valve

rgraham

this is the model 354 immediately
after the test

rgraham

do these help?

STEVEusaPA

That's an older, discontinued model. I just looked it up, didn't realize it didn't have a display.
Do you have the manual? If not you could probably use the manual for the 360 as a guideline for checking/troubleshooting, or give Tekmar a call tomorrow and see if they can send you a manual.

neilc

can you determine that the circulators are working?
pink one first, then the green zone circ?

why the mixing valve?
is this a radiant system?
did someone turn it down all the way as it looks now?

rgraham

i think i can find a manual for the 354 online somewhere. yes, it is a radiant system. i believe i took the picture during the test sequence. that's why it is looks turned down??

rgraham

i think the circulator motors are working. they sound like they run during the test sequence.

rgraham

i just checked the two motors during the test sequence. I can definitely feel the pink motor turn off/on when I flip the motor switch, however, i can't feel the blue motor turn off/on. i don't know how conclusive this is.

rgraham

question: is there a way to manually control the mixing valve? If so then i can probably circulate water thru the return line that way??

rgraham

i found a data brochure on the 354 online. still looking for a manual. would there be a repair/troubleshooting section in it?

neilc

so with the system set normal,
and the thermostat calling for heat,
do you hear the circs run?
Can't be if the heat isn't moving from the boiler.
you need to figure what's not calling the circs on.
do you have 24 v on each transformer?

neilc

rgraham said:

i just checked the two motors during the test sequence. I can definitely feel the pink motor turn off/on when I flip the motor switch, however, i can't feel the blue motor turn off/on. i don't know how conclusive this is.

ok, so if the pink circ is running you have hot pipes in and out of the boiler, correct?
and you're not feeling hot on the return from the radiant zone, correct?

the blue circ is what you need to run to pump heat thru the radiant zone.

the mix valve should be controled by OA temp reset,
I don't see a digital readout for outdoor air, do you?

STEVEusaPA

I couldn't find the manual online, only the replacement the 360. I would follow the set up for checking voltages and ohms across the proper terminals. Especially if your getting a red light for WWSD. I'd ohm out that sensor and it's related terminals on the control first as it may just be telling the control it's too warm to turn anything on. I wouldn't worry about any components until you are sure the Tekmar is working properly.

neilc

neilc said:

the mix valve should be controled by OA temp reset,
I don't see a digital readout for outdoor air, do you?

OA or Room sensor , , ,

rgraham

"so with the system set normal,
and the thermostat calling for heat,
do you hear the circs run?" when I turn off the switch for the pink circ motor I no longer hear a hum. the pink motor is on the house side of the mixer valve. Not the same for the blue circ motor. I don't hear any hum or noise when I switch the motor on/off at its switch.

rgraham

is it possible for the water to be circulating in the system if thermometer on the return line on the house side of the mixer valve and the thermometer on the furnace side of the mixer valve reads 60 degrees?

rgraham

"Can't be if the heat isn't moving from the boiler.
you need to figure what's not calling the circs on." To be sure I understand: I measure 160 degrees on the thermometer on the furnace side of the mixer. I get the same temp on the thermometer on the house side of the mixer.

neilc

right,
and as Steve says above,
you gotta put on your electrician / troubleshooter hat and dig in to why,
which and what sensor reading is incorrect,
or prove them right and check the outputs also,

you need to ask yourself if you're over your head here, or not.
https://heatinghelp.com/find-a-contractor/

rgraham

I don't see a digital readout for outdoor air, do you? no there is no readout

rgraham

you're not feeling hot on the return from the radiant zone, correct? correct, i am not feeling any hot on the return from the house

rgraham

you need to ask yourself if you're over your head here, or not.
https://heatinghelp.com/find-a-contractor/ Thanks for the concern. At this point, I'd like to get a little heat going in the system if I can. I plan to try and find a contractor tomorrow when the rates are back to normal.

STEVEusaPA

You ohm out the sensor and compare your reading to a chart. That will tell you if your sensor is reading correctly.
https://www.aetsolar.com/literature/Manuals/TempVsResistChart.pdf
Like I said earlier, just follow the 360 manual, and check terminals for proper voltage, and ohm out the sensors (compare to chart) to see if they are reading properly.

neilc

could you post one more big picture of the whole system,
(the control and pump board, and the boiler together)

rgraham

okay - thanks. i will find a multimeter and see if I can take some measurements

rgraham

am i measuring anything in addition to the two temp sensors (oa & return to furnace)? I don't see anything in the datasheet.

neilc

this is a little difficult cause we can't see a digital readout of sensors, and someone needs to meter them and know the values make sense.

try tweaking the "max supply" setting up all the way, count to 5, and set it back down to where it was,
does anything change?
try the same with the "heating curve",
be sure to set these back to where they are now.

on the blue circ that you don't hear a difference when you switch it,
try tapping on it, gently, motor and circ housing, gently, as you switch the switch, gently, don't ding anything.

rgraham

taking another picture(s) of the whole system

rgraham

Whole system top left view

rgraham

Whole system bottom left

rgraham

Whole system top right

rgraham

Whole system bottom right

rgraham

Furnace supply & return lines are up above out of view

rgraham

Neil - just to be sure, when you ask me to meter the sensors, I have what looks like a thermistor that is attached to the furnace return pipe and I assume there is a similar sensor for the OAir. Are there other sensors also that I should be measuring?

rgraham

tapped on the blue circ motor. No difference. no detection of the motor trying to spin.

neilc

I don't have your manual,
so it's hard for me to say.
@STEVEusaPA might better answer here,
definately the thermistor you see on your piping,
and any other input sensors in the manual,
Do you have the manual?