I apologize, haven't read full thread. Sorry if these are old ideas. Have you made sure everything is sized correctly for the box/ wall thickness? Is there a stat/ solenoid? What about a door switch? Suction line heat exchanger? Power head an SZ? As long as you have superheat, the comp should be ok
Last edited by Rwilson404; 07-11-2013 at 12:32 AM.
Reason: Wasn't done
Well; after my first glance I started off with the late night hip-shoot "diagnosis" that the TXV was defective / not feeding. So I checked the compressor HP (1/2 HP) and then chose a 1/4 ton valve because that is about what flows enough BTU's at a -10º F. suction. When replacing it I found that the "bad" TXV was both the exact same valve AND was clearly very new. <g>
I called the box maker; Norlake and got the original specs: 1/2 HP K body Copeland compressor - they did not know which one they had used.
The almost-new compressor was then found to be rated from -40º to 0º F. That was the second WTF moment.
The ZP valve would only feed to a 50 lb. suction. This took very little refrigerant in the warm evaporator coil. The resulting refrigeration effect was very small. So the box stayed too warm to ever let the suction pressure reduce enough to allow the TXV to feed more refrigerant. A catch-22 loop.
1. I have never in my life seen a Norlake box which would do what it was rated to do.
2. A half horse compressor is what should be on a single door reach-in freezer - not on a six by six walk-in.
3. A 3/4 HP -10º condensing unit was less expensive than the correct 1/2 HP K body - and plus; the old condenser was filthy with gummed on fryer grease that I had no interest in touching.
So I installed the 3/4 HP Copeland tin can condensing unit the customer needed.
This worked better but subsequently it was discovered that on an earlier visit by one of the others in my peer group the system had been improved by eliminating the fan delay, the defrost termination, and all the wiring associated with them. And they also set up the box for four 45 minute, time-terminated defrosts per day. I found to my painful surprise that this both increases the evaporator to a skin-blistering heat level And also serves to heat the box substantially when the fans come on as soon as the defrost times out.
I don't have a whole life to continually devote to this project so at this point I have the larger condensing unit holding the box temperature at about 9º F. using four 15 minute minute time-only defrosts per day.
As soon as I get some free early morning time I am going to rewire the system to re-include fan delay and evap coil temperature termination of defrost.
That will not be today however. <g>
BTW: This is a Norlake box. Norlake is a company which apparently dismisses such frivolities as sufficient wall thickness, solenoid valves, a door switch, and a suction line heat exchanger.
Originally Posted by Rwilson404
The conventional view serves to protect us from the painful job of thinking.
Is it possible to improve with a simple TimeDELAY on the defrost start timer/ set-up, and adjust so that for another 3 or 4 minutes, the defroster does not kick in (D on mk); and if not yet installing last posted changes to do....? (you know, if still getting defrosted-enough to drop more temp)
Originally Posted by Poodle Head Mikey
M: ya Probably have seen the gas-mask required -- or hold breath and run-from vapor:
of solvent that really works nicely on old gummy-bear cdsr fin clogged w/ kitchen greazzzzz (!)
(I saw you did not wanna...)
the What's above:
Were are the temps at 5 am? before the door opens? Just 9 ?
-OF 9 subways - just have not any Norlake control issues yet nor problematics...
but they run cheaper on getting them to switch their uty electrics and gas billings at CCM's options energy team choice improvements...(!) and I get the portion as an adv fee as a commission every time they turn on the power/heat! (enrolled 87 / 18 commercially !
Did find fitting on the compressor needed tightening, and recharged new rfg.
Pan under evap that was not draining was just tapped-bent differently than OEM to then drain...
Still curious as to what your end is, let us know, pls.
I'll use less abrv-French next time.
But they are cheap. If I remember the coolers used to be ok in the 70's. But that was then and this is now.
Originally Posted by Poodle Head Mikey