compressor discharge tempertures and random cut outs

Discussion in 'General Discussions' started by moey, Dec 31, 2013.

  1. moey

    moey Member

    We have been having a problem with our unit cutting out. By cutting out it will be running and there will be a call for heat and it will stop fan and compressor sometimes just the compressor. A couple minutes later the fan will come on a couple minutes later the compressor and then it will run again. It does not happen very often maybe once or twice a day on very cold days <15F. There are no error codes. Generally happens in stage 2. The thermostat indicates a call for heat.

    Also I have also noticed our compressor discharge temps generally reach a steady state between 180 and 190 is this normal?

    Heres what we have:
    Climatemaster tranquility 22 5 ton water to air installed April 2013
    3200 ft of ground loop about 5-6ft deep
    Current EWT is about 34F
    Central Maine

    Our Dec electrical usage for the unit is about 1800kw.

    The installer has come out and looked at it once, they are not sure what is going on yet.

    Could this be related to the CFM my fan is at? I increased the Stage 2 fan speed from 1500 CFM to 1650 CFM on stage 2. 1500 CFM was the min setting recommended in the install manual. Since increasing it I have not heard the problem.

    Any ideas? Thanks in advance.
    Last edited: Dec 31, 2013
  2. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    I've seen similar posted before regarding Climatemaster control boards.. It sounds like this is what's happening. You've no error codes. As long as it comes right back after the 5 minute delay, that's how it was designed. Some would question the logic here, but it is what the engineers put into the control board.

    Extended Compressor Operation Monitoring - If
    the compressor relay has been on for 4 continuous
    hours, then the control will automatically turn off the
    compressor relay and wait the short cycle protection
    time. All appropriate safeties will be monitored during
    the off time. If all operation is normal, and if the
    compressor demand is still present, the control will turn
    the compressor back on.

    From: Page 8
    DXM2 Digital
    Heat Pump Controller
    Rev: 8 Oct., 2013J
    moey likes this.
  3. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I think WF throws a code if compressor has been operating for 18 hours straight, a more reasonable arrangement, given that 4 hours continuous operation is quite reasonable for a two stage system. It's a nuisance, not the end of the world, though.

    The discharge temp seems a tad high to me given the 34 EWT, but may be OK for a 5 ton compressor in high stage. I'm not sure what evaporator superheat that system runs at, and that figure impacts discharge temperature, among other factors.

    60 kwh / day suggests 12-16 hours operation per day. That seems excessive but may be OK, given how cold it has been (up there, anyway. 70s here, windows open, sole heat pump in use is warming pool water...) Key to know would be prior year's energy burned during period of similar cold. If system has a properly plumbed desuperheater, you should be getting lots of hot water at quite low cost.
  4. moey

    moey Member

    Interesting it has always happened early morning when the "cut out" occurred. I have never had it happen on a warmer day when the unit is cycling more often. We are due for some below 0 temps the next couple days Ill keep a ear out. I wonder if increasing the CFM caused my thermostat to cycle a little bit more. Last night it was -5F it held steady at 70F switching between stage 2 and stage 1 not sure if it ever shut off last night. Its slightly oversized right now because we have a 700 sq/ft that is not being conditioned yet.
  5. moey

    moey Member

    Took a look at the log I had of the "cut outs" only happened twice in the same day sure enough it was about 4 hours apart. Both days it was below 0 and didn't get much above 10F during the day so its likely it was running continously. Will pay attention the next couple days we are supposed to see -20F in a couple days.
  6. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Climatemaster heatpumps cut off the compressor after 4 hours for a couple minutes, that is likely why you see this on colder when the unit has a longer runtime. I don't know why, it does not make any sense to me. WF does not, they keep running forever.

    You can see a WF here running at least in 1st stage for the last 24 hours.
  7. moey

    moey Member

    Thanks I find your systems interesting to look at online. It really gave me a good idea of what to expect cost wise per month. Although sometimes I look at them and think gosh this person is only paying $100 per month and then I think well there house is 30 years newer and its been below 0F for 10 days in December where Im at.
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Here is a Climatemaster system, you can see the 4 hour compressor cut off every 4 hours on the LWT, LAT and DSH out.
  9. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    Something totally separate but about the fan for installers and techs out there. I have had (3) fan molex plug connectors with loose wires on CM TT27 units that would give us intermittent fan problems. The first one we thought was the motor so we swapped it out and it happened right away again. Did some further investigation as we probably should have before we pulled the motor and some of the wires in the plug had become loose. The two other CM units were put in service around the same time and had same issue with the plug. No big deal, just a pain to go back to customers house and make a quick fix for them. just an FYI for folks. These few units were installed summer 2011.
  10. hardchines

    hardchines Member Forum Leader

    Sounds like your system is fine, a FYI would be a simple loose connection on the primary power relay or a relay with a burned contact, can give you the same M.O with no fail log.
  11. johnny1720

    johnny1720 Member

    During the time ClimateMaster takes it cute little break, does the electric resistance kick on if there is still a call for heat during that break.
  12. dgbair

    dgbair Just a hobby Forum Leader

    The tstat does not know the unit is taking a 5 min break... so as long as you don't cross a tstat threshold which would call for aux heat, the resistance heat will not kick in.
  13. ssmith

    ssmith Member

    Glad to see the explanation for this. I first noticed this on my own system last winter. I thought there was something wrong at first, then finally decided it was just normal operation...for whatever reason. I only notice it after a night of below zero weather, when the system has been running on stage 2 all night. Of course, this is a time when you don't want the system to shut down for a few minutes. Aux doesn't come on at all during this, but if you're on the edge, and the temp drops a degree while the system is daydreaming, then it's not unusual for aux to come on shortly afterwards. No big deal, though, as aux just stays on long enough to boost the temp. back up...15 minutes at most, in my case.

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