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cast iron baseboard advice

Perry_3
Perry_3 Member Posts: 498
OK, Then the other way that I see it working well is to 2 pipe it, with each section of CI baseboard recieving its own supply and return pipe.

This would also be a great application for TRV's on the radiators.

I note that TRV's should not generally be used on a monoflo T system because the muck up the required system flow (per ITT's instructions on monflo systems).

Just be sure you have large enough supply and return mains.

I note that not a lot of people seem to understand monoflo systems. I was advised that I needed to split my system by some, others told me that I needed to put TRV's on my radiators (a no no with a monoflo system unless you have a bypass). Yet, there was nothing wrong with it and it works great. My current circ pump (Taco 007)is pushing more gpm than the old one as evidenced by the low temperature drops in the system now (ranges from 5 to 10 degree drop versus the previous 20 degree drop). All that means is that my CI baseboard is all a nice even temperature arround the house.

It is a very simple system that works very well if done correctly.

Perry

Comments

  • ralman
    ralman Member Posts: 231
    cast iron baseboard advice

    I removed my 50+ year old black iron monoflo T piping system that was connected to Burnham baseray cast iron baseboard. This is what I noticed; in most cases the baseboard touches the wall on both ends and the majority of the risers have very little clearance between the wood where they go through the floor. Some risers actually touch the wood. At least one hole is not close enough to the baseboard to allow the angle valve union to draw tight(I haven't finished inspecting all the risers). The installation manual specifies a 1.25" x 1.50" oblong hole for .75" risers going through the floor. I did not have any expansion noises with the monoflo T piping. Do you think I will have trouble with expansion if I don't enlarge the holes going through the floor? If I do enlarge the holes I don't see any where the baseboard itself will expand to since it is against the wall on both ends. Do the end caps absorb the expansion? Baseboard expansion rate is 1/8th inch per 10 feet of run. My longest baseboard is 26 feet long. Any thoughts would be appreciated.
  • ScottMP
    ScottMP Member Posts: 5,884
    I would rather

    enlarge the holes and not worry about basebaord expansion. I never had (25 years in business ) problems with the baseboard expanding. The risers on the other hand .... You've nver had a problem ??

    More of a concern is that you removed the Mono-flow system. Be carfull how you pipe this. Cast iron baseboard wants a monoflow or scoop system. DO NOT pipe this like a copper fin job.

    Scott

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  • ralman
    ralman Member Posts: 231
    Thanks Scott.

    I didn't hear any noises at all from the heating system, so my perception is expansion rate with the monoflo piping was not a problem. My thoughts were that any piping method would work with cast iron baseboard, but I am thinking that the different methods might produce more expansion. I don't want to fiddle with removing all the risers and baseboard connections to enlarge the holes unless it is absolutely necessary.
  • Perry_3
    Perry_3 Member Posts: 498
    What were you trying to gain

    by removing the monoflo T system.

    This is generally a great system; and I don't see any real advantages to removing it.

    Note that I installed a Vitodens 200 last year in my house on my mid 1950's era monfow T system and it works just great (I used the RS sensor to replace the old thermostate).

    Perry
  • ScottMP
    ScottMP Member Posts: 5,884
    Ross

    Its not the expansion noise that drives the piping method, its the mass of the cast iron. If you pipe it in a loop, going from BB to the next you'll have uneven heat. The first ten feet will suck so much heat out of the loop the next ten feet get markedly lower temperature water. This continues thru the loop untill the last sections won't heat at all. A mono-flow or scoop system will give heat to the BB and continue on to the next section, suppply all sections with ( close to ) the same temperature water.

    Cast iron basebaord is great heat but needs to be piped properly. Don't fool with the piping design or have a pro check it out.

    Scott

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  • ralman
    ralman Member Posts: 231
    Perry

    I had posted a diagram of my system months ago and it was discussed in detail and several problems were noted from the discussion at this forum, removal was based on those previous discussions.
  • ralman
    ralman Member Posts: 231
    Single loop design

    I actually planned to repipe to three series zones. As an example, one zone would have 63 total feet of CIBB. The calculated head loss of the zone and circulator selection yields a 4.6 GPM flow rate and a 15 degree temperature drop. I have tracked/calculated the heat output of the CIBB as the temperature drops around the loop. My heat output of CIBB exceeds the calculated heat load for every room except the last room on the circuit, a bathroom. I calculate 425 BTUH short in that room and had planned on replacing it with a high output fin tube which will put me 300 BTUH over the design load for that room. Uneven heating across the loop for sure due to lengths/outputs of the CIBB exceed/fall short of the design calculations. You both have me worried about my calculations. On paper, A 3/4 zone with 63 feet of CIBB, 4.6 gpm flow, 15 degree temperature drop is acceptable. Your feedback is appreciated.
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