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Weil Maclain Ultra optimization

Brian_19 Member Posts: 115
If you have a laptop computer get the interface kit it is very cool. I hook up the laptop on all installations to set the parameters just point and click.

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  • rn
    rn Member Posts: 13
    Weil Maclain Ultra optimization

    I recently installed an Ultra 155 and now I want to optimize it. I have installed the outdoor temperature sensor, but has been too cold for it to be a factor so far. My assumption is that I want the boiler to run 100% of the time on my coldest day. Is this correct?

    Since this is a modulating boiler, is it true that I don't want to have more than a 3 or 4 degree difference between my daytime and night time thermostat settings?

    I have began playing with the outlet water target temp. With the out of the box setting of 190 on a day in the low 30's and night in the 20's the boiler ran for 9 hours. Since we rarely see single digits in philadelphia I think it should have run for 14 or more hours for better efficiency. I have lowered the output temperature target to 180 degrees and I'll see how long it runs.

    Should I consider disabling the supply temperature boost? 10 minutes seems like a short window.

    i never knew you could geek out over a furnace. now if that PC interface kit wasn't so expensive.....
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Speaking for Mod Con Boilers in General..

    And to your points:

    1. You want any boiler to run as long at a steady state as possible. With Modulating Condensing boilers this is possible with the operation tailored to the load or in advance of the load when OA temperature is factored in. Not steady-state per se, but better than "on-off" control by far. Also when on low fire, all of that surface area is fit to absorb more heat from the flue gasses.

    2. Setback temperatures is a subjective issue and open to debate, but the reality is applicable to your house only.

    You can "drop the bottom out" of your thermostat at night and see how low the temperature drops on its own at a given outdoor temperature. Some houses hold heat well (tight, well-insulated) and no matter what you do, the temperature only drops so far. (What's not to like about that?)

    Other houses drop rapidly and recover more slowly. Each house has it's own profile. A data logger setup is useful for recording and analyzing the conditions.

    Short of it is, German practice generally has 8 degree F as the optimum setback (granted with German housing standards which are very high). If you have radiant floor with high mass you may want to set it back less. Low mass you may go with more. Point being though that the heat loss is dependent on OA/Indoor temperature relationships. The lower you go the more you save until you find it takes four hours to warm the place up. Check the cost of fuel for warm-up over the cost of no operation as the indoor temperature drops. With abundant radiation you can pick up faster and in a more efficient mode by the way.

    3. The target temperature is the one that heats your house on the coldest day. If you have a surplus of radiation (by conventional 180 degree F. water sizing standards), it could be much less. The more radiation you have, the lower that temperature needs to be. You are correct in that experimentation is key. Try it and see what works. In my house, 140 works fine on the coldest day, 110 on milder days. I have a mix of Runtal panels/convectors and cast iron by the way. Your results will vary.

    4. Ten minutes for a temperature boost seems fast. Again, check the fuel use. I suppose if you have enough radiation to support that and it can do so with water in the condensing zone, go for it. That fast a recovery? May indicate you can tolerate a deeper setback.

    5. On becoming attached to this technology: Meetings are held Wednesday evenings in church basements everywhere. First names only; coffee is always on. :)
  • Floyd
    Floyd Member Posts: 429


    Why on earth did you hookup the Ultra with the DHW hooked into the Taco realy instead of directly into the boiler? You now connot run the separate water temps., all that pipe will heat up in the summer, and you could have set up separate modulation for the hot water. In fact the Ultra has a different modulation for the DHW that will allow it to modulate up quicker.
    Don't mean to sound harsh, but it would seem that you shot yourself in the foot here. That installation could have been way more eff.

  • Floyd
    Floyd Member Posts: 429

    There are a number of things that you can do to trick out that boiler!!!
    Frist, turn the boost right off.
    Then back down the water temp. till it don't keep the house warm, then bump it up just a bit.
    Then take the low temp. of the reset down to 0 or at least the single digits somewhere. It is factory set at 32, which is way too high.
    Then start backing down the fan speed for the space heating side of the boiler till you start to not keep the house warm again, then bump that back again a bit. This will not affect the DHW side and you will still make hot water okay if it is hooked up correctly.
    Now you will not want to set back much, because you will not have the pickup factor to raise the temp. back far. I go 2 degrees at night. But you will get very eff. operation and be in condensing mode, most, if not all of the time, and the boiler will be running way more than it's off.
    Best thing is that the wife, and/or kid's can play with the t-stat all they want and never get the temp. in the house much above set point!!!
    All the settings can be done through the front of the boiler allthough the PC interface makes it much easier.

    Have fun play'n!!

  • Harold
    Harold Member Posts: 249
    RE photos


    Next time they beam you up to the mother ship try to get some photos of the command bridge.
  • Bob Sweet
    Bob Sweet Member Posts: 540
    No kidding!

    Beam me up Scotty! Nice job Floyd. WM's gotta like that.
  • Brian_19
    Brian_19 Member Posts: 115
    Look again

    Don't bash a job by one picture. The water heater is not hooked up to the taco relay. Take a look at a different picture. The water heater pump is wired to the boiler.
    Next time ask first before making false negative comments.

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  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Holy Shinola!

    You think W/M is going to love that? How about Taco? :)
  • Glenn H
    Glenn H Member Posts: 14

    Gotta ask, Whats all them transformers for??

    You have zone valves all over the place?
  • Doug Bird
    Doug Bird Member Posts: 22

    Taco's diggin' it too! Heckuva job Floyd.
  • Doug Bird
    Doug Bird Member Posts: 22

    Taco's diggin' it too! Heckuva job, Floyd. Well done.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    My assumption is that I want the boiler to run 100% of the time on my coldest day. Is this correct?

    Partly correct. For optimum efficiency you want the boiler to run 100% of the time whenever the total heat loss of the house is higher than minimum boiler output. Such is the actual purpose of modulation.

    You can get pretty close to this ideal with a system using traditional wall thermostat(s). How close you get depends on two things:

    1) The balance (both of emitters and t-stat settings) between zones.

    2) How much speed you're willing to give up when thermostat setting(s) are raised.

    With a system with wall thermostat(s), if the boiler is running 100% of the time it means that the supply temperature is at a minimum--only able to maintain conditions--NOT able to increase space temperature.

    As Floyd mentioned you can get the boiler curve set such that raising a thermostat really doesn't do anything--or at least does it very slowly... This also means that any daily setback must be minimized or eliminated unless the controller "understands" that you have called for a rise in space temp.


    With thermostatic radiator valves (TRVs) or floor heat valves (FHVs) which are proportionally operated two-way flow devices, the situation is similar, BUT:

    While you will ALWAYS and AUTOMATICALLY get 100% boiler operation whenever the house heat loss is above minimum boiler output, the supply temperature is not necessarily minimized. Why? Because the TRVs/FHVs will "do their thing" and just reduce flow to maintain setting. While you can retain the ability for very rapid response to a request to raise space temperature by maintaining a significantly higher than necessary supply temperature, the price is reduced efficiency when you are maintaining space temp.
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