Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

TRV design

Options
Wayco Wayne_2
Wayco Wayne_2 Member Posts: 2,479
We are renovating a house with 15 existing radiators. We are running pex tubing to each radiator from 2 manifolds and installing TRV's on each radiator. We want to use variable speed circulators so they can ramp their speed up and down according to the amount of open TRV's. Questions: How do we initiate the heating cycle? What happens if all the TRV's shut down and the circs are still running?

Comments

  • EzzyT
    EzzyT Member Posts: 1,296
    Options
    Outdoor reset would initiate the heat cycle and you would use TRV valves with a bypass or have a dedicated port on the manifold that would be your bypass.
    E-Travis Mechanical LLC
    Etravismechanical@gmail.com
    201-887-8856
  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479
    Options
    I like the bypass idea. I'd have to add a loop to the manifold though.
  • hot_rod
    hot_rod Member Posts: 22,246
    Options
    If you use a delta P pump, no need to bypass the pump will adjust to the no flow condition.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GrallertPaul S_3Ironmandelta T
  • clammy
    clammy Member Posts: 3,113
    Options
    what i have done at my own system and just about all trv panel rad system i have installed is to use the by pass valves at each rad .That way any trv that is closed it just by passes at the rad there are alot of bonuses to this type of lay out a few are the fact that you can balance ur rad flow from your manifold on the flow neccassary to get your btu rating out of your rad ,being u have flow through all of your loops there s less of a issue when they run through unconditioned spaces and allows your to use that volume of water flow through your system as a small buffer some thing that would not happen when using the standard non divertor valves .As for controls i like using a temperture averaging thermostats with remote sensors mounted in high load areas and fire the boiler according to the average temp.( usually a white rodger) i know that alot will say to run off outdoor temp but from my experence it seems that in alot of cases your boiler pump will continue to run and from what i have seen i have noticed more of a temp drop across the boilers heat exchanger then from the system and the boilers temp sensor fire the boiler even when your indoor temp is satisfyed i would guess that if u really lower your outdoor reset temp valves and fine tune it the issue may not occur but i have found that a temp averaging stat with say a boiler buddy properly sized works very very well .what i usually do is use a ranco etd control to bring my system pump to run consant at a pre set temp ,the temperture average t stat just cycles the boiler and water temp is determeined by ur outdoor reset .Hope this helps but i would say is when installing buderus or dianorn panel rads use the by pass divertor valves they are avaiable from oventroupe .I had seen these by pass valves in use years ago while in germany .The other plus is that they divert i believe about 40 or 60 % flow so velecity noises are not a issue which i have seen mostly heard when non divertor valves are used with out a system a pressure differental valve or a pressure variable pump.In my own system i have no buffer tank not enough room but used system by pass valve but recently changed out my 15 -58 for a wilo and got rid of my system by pass works like a charm .Running max temp about 135 at design which i set for 15 . on a small note i had found that using system sensors wheater on a pipe or in the buffer tank well caused unwanted cycling of the boiler and no real bonus as for building temps and comfort i just let the boiler on board temp sensors call the shots but these where systems using panel rads not standed c i rads and of couse a higher gas usuage but thats just my experence Hope this helps you out peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
    Rich_49
  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479
    Options
    Thanks Clammy!
  • hot_rod
    hot_rod Member Posts: 22,246
    Options
    My friend Nathan White up in Alaska used a low current Phenix induction relay on the circ pump. When a TRV opens, it wakes up the delta P circulator. The relay will sense down to .1 amp so it calls on the boiler.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jumper
    jumper Member Posts: 2,282
    Options
    I'd just install a bypass that has adequate flow & resistance to satisfy pump when all TRVs are closed. When a TRV or TRVs open resistance goes down and flow increases. If you've selected a correct circulator & you read its curve properly.
  • hot_rod
    hot_rod Member Posts: 22,246
    Options
    jumper said:

    I'd just install a bypass that has adequate flow & resistance to satisfy pump when all TRVs are closed. When a TRV or TRVs open resistance goes down and flow increases. If you've selected a correct circulator & you read its curve properly.

    How do you fire the boiler?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jumper
    jumper Member Posts: 2,282
    Options
    hot rod said:

    jumper said:

    I'd just install a bypass that has adequate flow & resistance to satisfy pump when all TRVs are closed. When a TRV or TRVs open resistance goes down and flow increases. If you've selected a correct circulator & you read its curve properly.

    How do you fire the boiler?

    I don't bypass the boiler. I bypass the TRV s