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Messages - broncodriver99

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Changfa Engines / Re: Changfa looking engine - ebay
« on: Today at 04:50:27 AM »
Farymann are made in Germany. I think they are popular in Marine applications and I know some of the military generators use them. Supposed to be very well made.

General Discussion / Re: Noob - Please help
« on: October 28, 2021, 02:29:37 AM »
I tried to access the shared drive but it requires permission. I sent a permission request however that works.

General Discussion / Re: Noob - Please help
« on: October 27, 2021, 01:01:21 AM »

Looks to be an HA2 based generator. Can you get a better picture of the generator head info tag? I have a manual for the engine but cannot make out what generator head you have. A good close up image and any other info would be helpful.

I would think it should charge the batteries. Could be something in the charging system has an issue or if it has sat for a long time may have lost it's residual magnetism. Does it produce AC voltage?

Lister Based Generators / Re: what is this
« on: October 21, 2021, 04:43:31 AM »
Is that another one in the last picture? If so, as 32 coupe suggested if you have a meter that reads capaicitance you can test the other one. I would imagine they are the same.

Lister Based Generators / Re: what is this
« on: October 18, 2021, 10:02:58 PM »
There may still be some readable info on it. It will either be rated in f (farads) or uf (micro farads), most likely uf. There should also be a voltage rating on it. Hopefully it is still readable.

Lister Based Generators / Re: what is this
« on: October 18, 2021, 09:59:45 PM »
It looks like a capacitor to me. Most likely for noise suppression and RF interference.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 31, 2021, 02:31:14 AM »
Also, a 60% reduction in cap tube length would most likely have you flooding liquid back, high suction, and low discharge pressures. I think you are only about 10-15% too long. You are getting enough liquid to get you to within your target SST just not enough to flood your HX and get your superheat down.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 31, 2021, 02:18:55 AM »
Your observations from today definitely lead me to believe it is refrigerant flow issue. You aren't getting enough liquid to flood your HX causing high superheat and high discharge pressure. Another side effect is high discharge temperature which will kill a compressor in short order, especially a rotary. Couple that with getting 13 degrees of subcooling with that small condenser and you definitely have a restriction, as in the cap tube is your limiting factor. Shortening it would definitely get you more flow.

I would ditch the cap tube at this point and go to a txv. You are fighting an undersized condenser and cap tube. It will be much easier to dial in your charge and the whole system in general with a txv. I think you could eventually get there by shortening the cap tube but it will likely take multiple attempts and if you go too short there is no putting it back. If you want to continue experimenting with the cap tube I would suggest getting a pair of service valves so you can pump the system down and isolate the cap tube and HX. Then you only need to evacuate that part of the system as you experiment. You will also need to change the drier at some point as each time you open the system up there will be some moisture and contamination that you will not be able to get out which the drier will collect and eventually clog. I change driers anytime I open a system for service. As a word of caution, if you do add service valves and want to pump the system down you will need to soak the condenser with cool water and monitor the discharge pressure. 410a builds head pressure very quickly and can be very difficult to completely pump down without exceeding the discharge pressure limits of the compressor and condenser coil.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 31, 2021, 01:51:39 AM »
Bronco, One more TXV specifications question if you can bear it, please.
Is the temperature range specification stating a maximum of  50F  for the TXV referring to the saturated suction (low) side temp, not the actual line temperature?  That seems an odd convention to me for a mechanical bulb sensing the physical line temperature, but every technical field has it's own conventions.

Yes, the specification is for saturated suction temp. And I believe that is not necessarilly a hard limit, they just can't guarantee as tight of control on the superheat outside of that range so it may work acceptably up to 55 degrees SST.

A TXV only trys to maintain the superheat setting, that's why the sensing bulb is attached to the suction line. The spring pressure inside the valve working against the pressure in the power head is designed to know what the suction pressure is and the sensing bulb senses what the suction temperature is and the valve will modulate open or closed to maintain the superheat setting that is adjusted with the stem under the brass cap. The operating/target load temperature range is set by compressor capacity and the inherrent pressure for either low/medium/high temp application. If the valve is set for 10 degrees superheat it doesn't care if it is maintaining 10 degrees superheat at -10 degrees or +45 degrees.

That is a pretty generic wide range valve. Valves can be built for specific temperature ranges depending on the application. Those wide range valves come in handy for field service or if say a manufacturer onky wants to have an inventory of a few txvs vs. one specific for each application.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 30, 2021, 05:02:13 AM »

I think you are looking at 2 different things

Correct. Saturated suction temp is derived from a pt chart for a given refrigerant at a given pressure. Suction line temperature is physically measured. The difference between the two is superheat.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 30, 2021, 04:58:43 AM »
I measured the temperature of the suction line about 10 inches from the evaporator/BPHE, in the 60's F.  You're saying it should be 50F or below?   I better retest that, well insulated.

You do want that line well insulated but No, you wouldn't want your suction line temp down to 50 or below at a 45 degree saturated suction temperature. Water being a much better heat transfer medium than air will tend to keep your suction line temp to within a few degrees of your fluid entering temperature.

I think your ideal pressures and temperatures once the system has been running for a little while would be a 45 degree saturated suction temperature(132 psi), and your suction line temp measured a few inches from the heat exchanger at about 55 degrees(10 degrees superheat). I would expect fluid entering temp to the HX at around 65 degrees and leaving temp at around 55. That would put your slab somewhere in the 65-70 degree range.

When you first start the system and the slab temperature is say, 72 degrees, you will see that your suction pressure, suction line temperature, discharge pressure, liquid line temperature, and fluid temperatures will be elevated above the "ideal" running conditions noted above as the chiller will be taking the maximum load it can. As the chiller displaces the heat from the slab and the slab temp starts to drop to say 69-70 you will see the operating conditions start to get closer to ideal. When the system has been running for a couple of hours and the slab is down to around 67-68 degrees you should see the "ideal" conditions noted above.

A TXV would make dialing in ideal conditions easier and would do a better job of keeping the system close to ideal during the slab pull down but isn't completely necessary. I don't think you are far off and my only real concern with your current conditions being the discharge pressure. If you can find a way to keep the discharge temperature down with shading that will reap significant gains in both efficiency and heat removal. My real concern is where is it going to be on a 100 degree day?

There is a lot more to system setup than just hitting target pressures and temperatures as all along the way you need to be thinking about component longevity, most importantly the compressor. A difference of a few psi, a few degrees, and a few 10th of an amp can make a big difference in longevity.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 30, 2021, 02:32:52 AM »
You are quite welcome.

As Gary said, your evap temp isn't your fluid temp. It is your saturated suction temp. I am guessing when you get everything dialed in you will be in the 40-45 degree range. I don't think your saturated suction temp will get above 50 degrees and if it does you are going to have bigger issues.

The two 1 ton valves are the same valve except one has a bleed circuit and the other does not. I would recommend the one with a bleed circuit for your application. It allows the pressures to completely equalize on the off cycle which a rotary compressor will appreciate.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 30, 2021, 12:44:41 AM »
The slinger ring is pretty much standard on window bangers these days, it helps deal with condensate and as you found they get some free evaporative cooling out of it which allows the manufacturer to use a smaller(and cheaper) condenser coil. As you suggested you need to be careful with your water source as mineral will build up pretty quickly and stop up the coil but it will also deteriorate the aluminum fins.

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 30, 2021, 12:39:01 AM »

Yes, that is the formula for sensible heat.


Here are links to some valves that I found that should work. TXVs for AC have an equalizer line that needs to be connected to the suction. It can either be a flare joint or it is a cap tube that will have to have a hole drilled for it, inserted, and brazed in. Or, you can get a piece of 1/4" copper flare it on one end and use a flare nut and crimp the other end around the cap tube and braze it. Valves have a range so a 1.5 ton valve should work it will just be at the minimum limits of it's flow. You can just use reducing couplings or bushings to match your connection sizes if need be.

- 1 Ton Valves:

- 1.5 Ton Valves:

Everything else / Re: DIY water chiller - reading suggestions?
« on: August 29, 2021, 12:35:57 AM »
It definitely looks like the cap tube is limiting you. But, my math shows you in the neighborhood of 11,100 BTU of heat removal which isn't bad at all. I definitely don't like that head pressure but with the small condenser in the window unit it isn't terribly surprising. That chiller is taking a lot of load right now. Maybe run it for a couple of hours and see where it settles out. I would bet your temps come down some more and as the slab cools a little your head pressure will as well. I would probably shoot for about 10 degrees of subcooling and a 10 degree td on the liquid side but that would be when the slab is down to operating conditions. You can control the load on the chiller by adjusting your water flow. Maybr try it just to see what it does with your head pressure.

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