I will be doing some tests on this system but have concerns about accuracy. AT times I get temp readings from my cheap thermocouple readers that has to be way off so I don't trust them at all. I just ordered some cheap thermometers to use instead, at least I expect these to be repeatable. It will be a few days before they arrive and then I will solder copper thermometer holsters to the lines coming out of the evaporator and compressor.
When I start this up it can take up to ten minutes for the temp out of evaporator to drop to 50F and the condenser is also slow to heat up. Once it gets past this start up period it seems to run OK. During this start up the pressures are both quite low. It is very inefficient during this time. Will a TXV help with this issue.
I have seen disscussion on this forum about possible differences between BBQ gas and R290. I think the P-T chart for my BBQ gas is about 8 psi offset from R290. This might be my measurement error. So I am going to try to develop my own P-T chart. Has anyone tried this. I will be working on this in the next few days and will come back with results.
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