I'm stumped and my wife's patience and understanding is stretching thin.  With some substantial support from these forum's I self-designed and installed my system (less the sheetmetal/ductwork) about 4 years ago ! :)  So far I've been able to work through any minor issues each time getting a better understanding on these systems, and I like to remind my wife my "crazy plumbing nightmare" has been saving us money for about a year now since the 3 year estimated breakeven point (when accumulated operating savings equaled upfront premium over propane forced air)and the system should last for a lot more years saving more every year as energy costs rise!  But now I'm losing some credibility, as I can't explain 2 mysteries.  Maybe someone can clear things up for me.

1st Mystery -  I have a Climatemaster TTV036 dual stage, pump & dump system, with a white rogers touch screen programmable thermostat (1F95-377) for control. Last night while the unit was running I went into the “installers configuration menu”, and changed the programming setting from 7 day to 0 (for non-programmable type operation), and then I changed the cycle rate selection from fast to slow (to increase run time and decrease number of starts). A couple hours later my wife notices that it is a little chilly the t-stat is set at 68, but it is only 66 in the house. The fan is running full tilt (high flow) consistent with 2nd stage, but I can hear the compressor is off.

I have the unit piped with a single Taco EBV (capacitor charged) zone valve turning the source water on and off. This valve allows enough flow for either 1st or 2nd stage. The second stage signal is wired directly to the hp board (instead of through a zone valve like the 1st stage). When I went downstairs to check it out I noticed that the zone valve signal LED was dark (as if there is no signal from the t-stat). When I opened up the service panel on the unit (while it is still running), the LED’s on the control board for the fan and 2nd stage (Y2) are lit but the one for first stage (Y1) is off. I don’t ever remember seeing this before. It seems like Y1 always stayed on when there was a call for Y2. I pulled the disconnect and checked the valve wiring to make sure nothing came loose, then turned power back on. After the normal delay the unit ramped up like normal, the valve opened and the compressor took off, with Y1 lit, and then Y2. Everything seems to run fine since then.

Any thoughts as to what took place ??
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2nd Mystery -  (My wife isn't aware of this one, yet )    I recently connected the desuperheater option using the dual tank “Bergy” diagram. After about 10 minutes in first stage the discharge stub out from the DSH felt noticeably warm to the touch, probably 15-20 deg F warmer than the intake stub out. Then 5 minutes later the stub-outs were about the same temperature (again via the venerable “hand test”), but the motor of the circulator pump was getting HOT. The impeller casing or volute was about the same temperature as the piping (way cooler than the motor end). Thinking there was something terribly wrong with the pump, I disconnected the pump wires. About one minute later the DSH discharge stubout began to warm dramatically again. Over the next few minutes the pump motor slowly cooled while the discharge stub-out got warmer and warmer. I wondered if this was normal operation.

Over the last few years I never noticed the DSH discharge stub-out being warm at all, but maybe that was because there was no water in the DSH circuit until now. Would air in that loop act as an insulator? That might explain the warm DSH discharge stubout, when the pump power was disconnected, but that still leaves me to wonder about the circulator pump motor.

Is it normal for the motor to get hot to the touch?

Also, although I expected a lower delta T and higher flow rate across the DSH due to very short piping runs (less than 6’), ¾” OD piping, and only one 90deg elbow. I am surprised that I didn’t at least feel some difference in the entering and leaving DSH water.

Again, does this sound like normal /correct operation?

air in the dsh circuit could keep water from circulating and damage pump.

Joe - I tried filling it from the bottom up, out the bottom of the tank, through the DSH and then up to the isolation valve right by the T at the tank cold inlet.  I have a check valve with a bleeder on it at the highest point of the circuit and opened it until a solid stream of water was coming out.  Does that sound correct? 

 

Mt experience is that circ pumps do run hotter than one might expect even when they are not vapor locked.

By "stub-out" do you mean water or refrigerant line?

In normal operation a DSH heat exchanger may reduce refrigerant tenperature by 30-60 degrees while increasing water temperature by just 3-8 degrees. The body of the pump will run appreciably hotter than the temperature of the pumped water.

Thanks for the replies...

By stub-out I mean the DSH water connections (in and out) sticking out the side of the unit (TTV036 climatemaster).

Last night I did some more observations, but I'm still confused.  The unit ran for 45 minutes in 1st stage.   After about 10 minutes of run time on the compressor, I did confirm that there is power to the circ pump but I can't tell if the circ pump is spinning.  The discharge stub-out gets warmer and warmer until its almost hot and then it stayed that temperature until the unit shut off (t-stat was satisfied).   The intake stub-out stayed cold the same temperature throughout this time.  This time however the pump motor stayed quite cool the whole time (even though the line it is piped in was very hot).   The difference in temperature between the intake and discharge stub-outs of the DSH seemed way to much.  Maybe now the motor is fried and not spinning and the heat is migrating down the discharge pipe?

The Taco website says to put a screwdriver blade on the motor end and then put your ear by the handle, then put turn power on/off to the pump to see if the noise changes to see if its even turning.  I'll have to think if there's any other test I can do without taking the pump appart. 

I will post back with results.  Any other ideas?