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older Tekmar control system

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Paul S_3
Paul S_3 Member Posts: 1,261
edited October 2016 in THE MAIN WALL


I recently received a call about a large residential hot water system that was experiencing control problems. A little background on this system. Home square footage is about 12,000 sq ft. There is about 20 low temp infloor heating zones and 2 high temp cast iron baseboard zones. and a 119 gallon indirect. Boilers are 2 cast iron direct vent water boilers. Control system now is Tekmar 252 boiler control/DHW, 371 house control (injection mixing for low temp infloor), 2 Tekmar 368 zone controls and 1 tekmar 367 zone control..... all thermostats are Tekmar rtu 055.... all controls are OBSOLETE.... General contractor called me once plumber and electrician couldn't get heat running..... home is being renovated etc etc etc.... I found about half the 055 stats at fault reading 0 ohms.... house control and 1 zone control is reading "internal fault error". Basically I have to replace the whole boiler control system. I really would like advice on what you radiant guys would do.... is there a benefit to Tekmar stats for infloor heating? would the system operate better with them? I'm not looking to repipe the boiler room or replace boilers..... boilers were changed just recently.... I was thinking of using regular circulator relays ( Like Taco (SR'S) or Caleffi ) with standard thermostats and just one Tekmar 374 control to stage the 2 boilers, DHW priority, and injection mixing for the low temp zones.... which direction would you guys go? ....Thanks Paul S
ASM Mechanical Company
Located in Staten Island NY
Servicing all 5 boroughs of NYC.
347-692-4777
ASMMECHANICALCORP@GMAIL.COM
ASMHVACNYC.COM
https://heatinghelp.com/find-a-contractor/detail/asm-mechanical-company

Comments

  • Zman
    Zman Member Posts: 7,607
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    The new tekmar stuff is really slick. It takes into account, out door reset, indoor feedback and can compensate for some pretty inbalanced systems.

    It also comes at a high price and has what can be a pretty confusing interface. Some customers hate the complexity and just want a t- stat. Others love feeling as though they are on the " cutting edge"

    I think it comes down to the type of system and the preferences of the customer.

    For the simple setup, I really like the wirsbo wt-1 t stat. It has some built in ability to control overshoots without the cost and complexity.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Paul S_3
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    For the customer who likes the simplicity of a thermostat I like the Honeywell visionPro 5000 series and I tighten up the differential to 1 degree for high mass radiant. Has worked very well for me. You have to make a judgment call if there needs to be multiple Temps in the radiant of if simply one outdoor reset control will handle the entire building's radiant with simple wall stats on a very tight differential.

    How is it zoned now? Manifold actuators, or zone valves flowing to zone manifolds? I have been replacing quite a bit of Tekmar controls as of late, seems 20 years if about the life expectancy. I do like Tekmar's flexibility and built in data logging for lead-lag boiler control etc.

    The sky is the limit, but many/most times the sky doesn't need to be reached with this stuff, I find simpler works better. Tight thermostats I find work the best in most of my installs, I shoot for "nearly constant circulation" with air room stats.

    Taylor
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Paul S_3
    Paul S_3 Member Posts: 1,261
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    No actuators.... zoned with circulators...Low temp zones are mixed down by variable speed injection...im going to give a price for pro5000's, Caleffi zone controls....and (1) 374 Tekmar....i would like to keep it simple....system hasn't worked correct for years customer tells me....
    ASM Mechanical Company
    Located in Staten Island NY
    Servicing all 5 boroughs of NYC.
    347-692-4777
    ASMMECHANICALCORP@GMAIL.COM
    ASMHVACNYC.COM
    https://heatinghelp.com/find-a-contractor/detail/asm-mechanical-company
  • Turbo Dave
    Turbo Dave Member Posts: 79
    edited October 2016
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    I have found indoor feedback from Tekmar thermostats paramount in achieving tight temperature control with radiant, especially in shoulder seasons and rooms with high solar gain. The performance improvement from the Tekmar communicating thermostats is substantial. The 532 is very basic. The 552 a high-end touch screen.
    Paul S_3Zman
  • Tinman
    Tinman Member Posts: 2,808
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    12,000 sf rehab has to have some serious coin involved?

    2 cascaded mod cons with low watt zone valves, buffer tank, and Delta P circ?
    Steve Minnich
    EzzyT
  • Paul S_3
    Paul S_3 Member Posts: 1,261
    edited October 2016
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    I wish.....customer is doing a major renovation....general contractor had there plumber replace the boilers....they installed 2 190 k direct vent williamson boilers....i was called in after when multiple zones weren't heating....im just there to replace control system
    ASM Mechanical Company
    Located in Staten Island NY
    Servicing all 5 boroughs of NYC.
    347-692-4777
    ASMMECHANICALCORP@GMAIL.COM
    ASMHVACNYC.COM
    https://heatinghelp.com/find-a-contractor/detail/asm-mechanical-company
    Tinman
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
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    Good to hear tekmar is attempting to simplify. Utterly ridiculous in the past, down the the thermostats. I avoid them unless absolutely necessary.
  • Turbo Dave
    Turbo Dave Member Posts: 79
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    The 400 series controls have everything you need in one control, up to 4 zones, with zone expansion easily done. The thermostats are now 2 wire also. My primary choice in controls, as we always have outdoor reset mixed supply temp in new installs. Much easier than the 1st generation to install, program and operate.
    Solid_Fuel_ManSWEI
  • bthirsk
    bthirsk Member Posts: 1
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    I just installed a Tekmar 374 to replace 2 older Tekmar controllers, a 353 and a 370. It works perfect for managing 2 different circuits with 4 zones, one a mass 1 and the other a mass 3. I would recommend to anyone.
    Turbo DavePaul S_3