Water-to-water heat pump rebuild? - Page 4

Mikesolar · 01-08-13, 06:51 PM

In Oz, I know this is true but not here. MAPP is still available, I buy a lot of it. There may be the same product you mention available here but I haven't seen it, but who knows, I've been wrong before.......

Update.....I'll bow to updated info. The stuff I used to buy is not what I thought it was. Maybe I should read the label.... haha

AC_Hacker · 01-08-13, 06:53 PM

Quote:

Originally Posted by Bill Sanford

R22 line temp entering the evaporator 43.7 degrees
R22 line temp leaving the evaporator 44 degrees
Source water temp entering the evaporator 49.9 degrees
Source water temp leaving the evaporator 45.5 degrees

So what are the temperatures before the TXV and just after the TXV?

There should be a very large temperature difference there. Just after the TXV the line should be drastically colder than going in.

-AC

Bill Sanford · 01-08-13, 07:59 PM

Quote:

Originally Posted by AC_Hacker

So what are the temperatures before the TXV and just after the TXV?

There should be a very large temperature difference there. Just after the TXV the line should be drastically colder than going in.

-AC

Yup, it is. The temp entering the TXV feels warm and is probably around 100 degrees F. Leaving the TXV is 43.7 degrees... the same as entering the evaporator since the line between the two is quite short.

MikeSolar: The dryer / filter is in the liquid line between the output of the condenser and the input to the TXV. The inlet and outlet of the filter are the same temp, so I don't think this is the issue.

Bill

Bill Sanford · 01-08-13, 08:04 PM

Quote:

Originally Posted by Mikesolar

Bill,
3] I still don't think you should start changing components until you look at the the filter first and then adjust the pumping in and out.

What do you mean when you say "adjust the pumping in and out." There are no adjustments anywhere in the system Even the TXV is the fixed type.

??

Mikesolar · 01-08-13, 08:07 PM

F/D could still be an issue. Is the temp coming out of the condenser the same as that going into the TXV? Maybe you answered this before.......

Mikesolar · 01-08-13, 08:09 PM

Quote:

Originally Posted by Bill Sanford

What do you mean when you say "adjust the pumping in and out." There are no adjustments anywhere in the system Even the TXV is the fixed type.

??

Adjusting the water flow through the condenser and/or through the evap. Fine tuning can be done this way. If either of the HX are too big or too small for the current conditions, they may be adjusted by valving or increased pumping, to some extent.

Bill Sanford · 01-08-13, 08:18 PM

Guys,

I also noticed that if I put ice on the TXV bulb, the temp dropped in the evaporator. When I did this, I also noticed significantly more output heat from the condenser into the load, although I didn't actually verify this with temp measurements because it was tough to keep ice on the bulb and measure anything at the same time! :-) It was pretty obvious to me just based on feeling the in and out lines that the load outlet water temp was heating up a lot more with ice on the TXV bulb. The TXV outlet line was also noticeable much colder.

It seems like the existing TXV is opening up too much and just dumping the existing R22 into the evaporator. The only reason the compressor isn't getting flooded is that the charge is so low that the evaporator is boiling all the R22 it's getting.

This is why I think changing out the existing fixed TXV with an adjustable TXV along with a full recharge will fix my issue.

Again, I could be wrong, but I've been reading a LOT and thinking about this issue for quite a while... No other answer seems to make sense.

Bill

Bill Sanford · 01-08-13, 08:20 PM

Quote:

Originally Posted by Mikesolar

F/D could still be an issue. Is the temp coming out of the condenser the same as that going into the TXV? Maybe you answered this before.......

Yes it is.

AC_Hacker · 01-08-13, 08:54 PM

Quote:

Originally Posted by Bill Sanford

Yup, it is. The temp entering the TXV feels warm and is probably around 100 degrees F. Leaving the TXV is 43.7 degrees...

I would expect that the temp coming out of the TXV would be in the neighborhood of 30 degrees or much lower... maybe even down about 20 degrees.

Yeah, I think the TXV is the culprit here.

You said your unit is 50K right? as in 50,000 BTU? That would be about right for 48,000 (4 Ton).

I saw a post where Steve Hull said, "A 24,000 BTU unit should be really pumping out the heat."

Where did he get 24,000 BTU? Am I missing something?

Have you mentioned what the specs are on your current compressor?

Have you mentioned what the specs are on your current TXV?

Also, there are specific mounting instructions for the TXV bulb, which line, how far from the compressor, on a horizontal run, firmly attached to the top of the line (or side), etc.

Your comment on how putting ice on the TXV bulb increased the output... That seems like a pretty serious clue here.

-AC

Bill Sanford · 01-08-13, 09:30 PM

Yes, it's a 4 ton unit.

I'm also not sure where Steve got the 24,000 BTUs from either.

I attached the datasheet for the new compressor in a previous post.

I don't have any information on the TXV and there isn't a model number or much info on it that I can see. I can just see "VX Charge" on it.

The bulb was attached at the output of the evaporator between it and the suction input of compressor.

01-08-13, 06:51 PM	#31
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	In Oz, I know this is true but not here. MAPP is still available, I buy a lot of it. There may be the same product you mention available here but I haven't seen it, but who knows, I've been wrong before....... Update.....I'll bow to updated info. The stuff I used to buy is not what I thought it was. Maybe I should read the label.... haha Last edited by Mikesolar; 01-08-13 at 06:54 PM..

01-08-13, 08:07 PM	#35
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	F/D could still be an issue. Is the temp coming out of the condenser the same as that going into the TXV? Maybe you answered this before.......

01-08-13, 08:18 PM	#37
Bill Sanford Helper EcoRenovator Join Date: Jan 2013 Location: Northern Minnesota Posts: 32 Thanks: 1 Thanked 0 Times in 0 Posts	Guys, I also noticed that if I put ice on the TXV bulb, the temp dropped in the evaporator. When I did this, I also noticed significantly more output heat from the condenser into the load, although I didn't actually verify this with temp measurements because it was tough to keep ice on the bulb and measure anything at the same time! :-) It was pretty obvious to me just based on feeling the in and out lines that the load outlet water temp was heating up a lot more with ice on the TXV bulb. The TXV outlet line was also noticeable much colder. It seems like the existing TXV is opening up too much and just dumping the existing R22 into the evaporator. The only reason the compressor isn't getting flooded is that the charge is so low that the evaporator is boiling all the R22 it's getting. This is why I think changing out the existing fixed TXV with an adjustable TXV along with a full recharge will fix my issue. Again, I could be wrong, but I've been reading a LOT and thinking about this issue for quite a while... No other answer seems to make sense. Bill

01-08-13, 09:30 PM	#40
Bill Sanford Helper EcoRenovator Join Date: Jan 2013 Location: Northern Minnesota Posts: 32 Thanks: 1 Thanked 0 Times in 0 Posts	Yes, it's a 4 ton unit. I'm also not sure where Steve got the 24,000 BTUs from either. I attached the datasheet for the new compressor in a previous post. I don't have any information on the TXV and there isn't a model number or much info on it that I can see. I can just see "VX Charge" on it. The bulb was attached at the output of the evaporator between it and the suction input of compressor.