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Thread: Do I need Primary / secondary piping?

  1. #31
    In the trades Dana's Avatar
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    Sounds like the overshoot is more of a thermostat issue- if you can narrow up the hysteresis delta on it you'd get shorter burns but lower temperature swings. Since you're burns are measured in HOURS, I'm not too worried about short cycling the thing. If all else fails a PID-algorithm Tekmar thermostat would deliver extremely tight room temperature control.

    A check valve on the condensate pump is one thing, but the drain trap something else. There needs to be liquid in the trap for it to function properly, and when the boiler is idling or off all summer the trap will dry out unless it has a regular source of water from somewhere else.

  2. #32
    DIY Junior Member Crooz1n's Avatar
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    Yes the inspector even said we'd have to watch it during the summer and keep some liquid in it. He said if we started to notice a smell then its probably dried out. Seems like the other way was better. At least it was sealed. Now the top of the trap is open.

    Do you or The badger have a recommended Thermostat model that will hold the room temp closer than what I'm currently seeing?
    Last edited by Crooz1n; 11-21-2013 at 12:17 PM.

  3. #33
    Master Hot Water Mpls,MN BadgerBoilerMN's Avatar
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    A thermostat may cure the overshoot but design water temperature is usually the culprit depending on radiation, insulation et al. As for the trap. We do find dry basement floor drains occasionally but most basements are damp and traps don't get much dry if filled once a year. A little glycol will slow the evap rate as well.

  4. #34
    In the trades Dana's Avatar
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    The PID T-stat recommendation was predicated on the " ...all else fails..." condition, eh? :-) We're not there yet.

    With burn times in the 2+ hour range it may be pretty close to the right water temp, but maybe not. The hysteresis in the thermostat may be way too high, or the anticipation is WAY off, creating a phase problem severe enough to induce a very low frequency under/overshoot oscillation if it's designed/tuned for low-mass radiation & oversized boilers. Let's see how it makes out with taking the anticipator function and differential to the limits on the existing thermostat. If there is a programmable differential on the thermostat, take that to the minimum too. Some are set to a fixed at 1F or 1C (or some other value), others can be adjusted to a pretty tight 0.5F or even less.

    In the meantime keep knocking down the programmed output temp at +16F by 10F at a time until it doesn't keep up. You take it in 10F steps adjusted daily you should find the bottom pretty fast. Then start bump it up by 10F to where it kept up in the prior and start decrementing by 2F daily. If the over/undershoots go away, great! If not, keep pecking around at the thermostat adjustment minutiae.

  5. #35
    DIY Junior Member Crooz1n's Avatar
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    Thank you gentlemen.
    I will continue to work SLOWLY with the heating curve. As I am leaving to go hunting for a few days and we are expecting a cold snap, I don't think it advisable to lower the temperature while leaving the wife at home.
    Since she is cold natured anyway I will wait until I return next week so as not to face the wrath of a cold spouse.

  6. #36
    In the trades Dana's Avatar
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    You can't convince her to go hunting with you? ;-)

    Good luck- I'm sure this boiler will eventually work out great, once you've dialed it all in.

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