Problem with HWW036 - Puttering out ???

HE is "Heat of Exchange". It's in the specification charts such that HE = source flow rate (GPM) * delta temp * 485. In this case with ground EWT @ 40 and Load EWT @ 100, the HE should be 24,400 btu.

The oil was between the top of the valve and the diaphragm. The diaphragm is sealed with a capillary tube to a bulb that attaches (clamped) on the suction line by the compressor. There is another capillary tube that is brazed into the suction line several inches before where the bulb is attached.

So if a TXV is clogged with oil, can this be resolved without replacing it?

 

While I don't know about oil, here is another fellow who reports 2 TXV failures http://www.geoexchange.org/forum/threads/do-i-just-have-a-lemon-tranquility-medium-temp-w2w.5934/


For what it is worth, in heating mode on this unit, the refrigerant flow is from filter to TXV with about 6" of pipe between. So all system debris except the pipe should get trapped. Perhaps there is something very fine and funky that gums up the value? I tested the TXV by moving the bulb between hot and cold ... it does not do anything which indicates failure.

As for a leak in the either coil, they are at 40 psi and 15 psi. Even with low suction pressures which occurred after TXV failure, these pressures are lower than the water pressures. Only during vacuum before recharge could water get into the system.

 

Mark,

Sorry about your wife's TBI. I am a brain injury sufferer myself ... and it can be hell on my wife as well as self. It takes doing tasks several times to ensure it is correct. So is frustrating and easy to get exhausted. It doesn't help to have problems like the unit with TXV issues, lol.

You mention "violently trips the unloader in the scroll compressor". Is this the clanking sound I hear sometimes?

As your one unit is unpredictable, try lowering the tank temperature setting to 80 F. Yes, it won't heat the home much at that temp but 'encourages' the problem in my case. What temp do you usually heat with? Is this a radiant floor application?

Have you made temp reading on the cold side of the TXV value? On startup, mine would get down near zero degrees. Of course your gauges would essentially give you the temps via a vapor chart.

 

David:

Thanks for the well wishes for Stephanie.

This unit was troublesome before I added the Tekmar 406 house control and a 120 gal. buffering tank. I have been playing with geos since the mid 70s.

The control logic is for 1 or 2 heat pumps to feed heat to the tank. I use a boiler to add heat to the tank when the loss is more than 10 tons.

The loops are deep in a large pond and even this winter I get a very steady 39 to 41* EWT even when the pond ices over. The pond is shown to the left.

The delivery system is a combination of high mass floors, (basement and garage) low mass staple up, (first floor) and a high velocity air system for the second floor. The house is 6,400 square feet will an additional 4,500 for the garage and walk out basement.

One unit acting up is not an issue for the heating system as the boiler will cover the entire load. I do need to get it working before cooling is needed.

My plan is to set up all of my test equipment, get out a good book and wait for it to make the noise that wakes my customer and more importantly his wife. I will run all the tests before condemning the TXV.

Mark

 

Have radiant floor, HePEX between joists. Been gradually putting in heat plates - messy job with insulation and zillions of screw tips protruding. But this is necessary in order to deliver heat at low temps - not much purpose putting in geo then running it at 130 degrees. It is amazing how much the heat plates help.

The only problem has been the actual heat pump. So far I've been charged $1800 in repairs on a new unit that cost me $4000 and isn't fixed right yet. Perhaps one more round to TXV change. Ground EWT is 40 and Load EWT is 100. Specs show COP 4.0 in this setup. I'm getting 2+ with the added bonus of the system occasionally locking out a minute into startup. Ironically, even with this problem and with electricity going from 13 cents/kw last fall to 23 cents/kw last month, its been far cheaper than heating with oil, the previous setup.

A factory rep is supposed to come and evaluate the situation - which I welcome. First it needs to be resolved. Second, I'm tired of getting the run around because of being a minor installer. Everyone blames flow, even though both engineering and measurement show flow where it needs to be. Besides if flow is high, you won't get lockouts ... you'll risk shortening the life of the coax due to erosion. And you don't get low delta T with low flow without something else being wrong. Am beginning to feel 'postal'.

 

David:

Lick two stamps and call me in the morning.

I do not think that coax erosion is an issue, but enough flow is.

Mark

 

The attachment to the suction line is on the side of a line that is vertical.

In this case, the oil was inbetween the diaphragm and the TXV, the 'external' diaphragm that pushes a pin. The 'internal' diaphragm is a sealed component with a bulb that straps on the outside of the suction line.