Thermoking SBIII only runs on diesel engine and not electric with code 10

[coldbox173]

Im working on a Thermoking SBIII Whisper Edition SR50 w/standby electric motor power.

Problem #1:
Starts and runs with diesel engine power with no codes. Does not start with standby electric motor, fails with code 10 (high discharge pressure).

Problem#2:
When I run it with diesel power, has a loooong temp drop time. (I also used an insulated false wall so its only cooling 4' of area.) Pressures are HP 300-350, LP 10-15. Ambient temp is 95F. I suspect the TXV causing a restriction?

My plans are to replace the TXV and power head. But why wouldn't it start on electric power? If the TXV was stuck, could that cause a code 10? If so, why would it run on diesel power?

Any ideas?
Thanks!

[manxaircrest]

Don't know if this helps however ....I had similar issue with similar unit .... code 10 etc turned out to be one of the pressure switches on the top of the compressor there are two, look the same with two harnesses going to them that are interchangeable, swap them and see if it runs in stby then .... if so swap them back when you want road sys and get new switch ..... as said don't know if this will be applicable or help but must be worth a go ?

[Kuhltek]

Hi there is a hp switch for diesel and electric as explained earlier.swap over hp switches and see if it will run on electric or does code 10 appear on diesel.... I am also thinking that for the slow cooling that the throttling valve pressure should be checked.i have had a few of these and generally the Txv being restricted too much to cool a small space I think would generate code 26 or 32 were as a throttle valve will generally not produce codes but will be very slow cooling with no codes

[coldbox173]

Don't know if this helps however ....I had similar issue with similar unit .... code 10 etc turned out to be one of the pressure switches on the top of the compressor there are two, look the same with two harnesses going to them that are interchangeable, swap them and see if it runs in stby then .... if so swap them back when you want road sys and get new switch ..... as said don't know if this will be applicable or help but must be worth a go ?

Yep, that was my thought also. So I tried swapping the 2 plugs on the 2 pressure switches and still the same result. There are actually 3 switches on this discharge manifold. The 3rd switch's plug is backwards so I wasnt able to do swap test with that one. I did check all 3 switches with a meter and they all showed continuity while unplugged. (If that is a correct test method) :rolleyes:

Another note....
Upon switching the unit to run on electric, I hear the microprocessor buzzing as it is about to start, then I hear a solenoid rattling like its leaking or maybe not opening or closing properly. Then it fails on code 10. This solenoid is located just over the battery and controls a small 1/4" line that also has a sensor (or switch of some type) on the same line.

Thank you for the reply and help!

[coldbox173]

Hi there is a hp switch for diesel and electric as explained earlier.swap over hp switches and see if it will run on electric or does code 10 appear on diesel.... I am also thinking that for the slow cooling that the throttling valve pressure should be checked.i have had a few of these and generally the Txv being restricted too much to cool a small space I think would generate code 26 or 32 were as a throttle valve will generally not produce codes but will be very slow cooling with no codes


Interesting, the throttle valve was replaced about 10 years ago. Perhaps it has a problem again. I checked suction pressure at the service valve above the throttle valve and showed about 20 PSI. Pressure at the port on side of throttle valve showed very low around 10-15. Head pressure was up around 300-350.

This unit has 13 lbs of virgin R507 in it and not R404. I wouldn't think this would be an issue though.

Thank you for your help and reply.

[coldbox173]

ok, I am thinking the solenoid valve on the 1/4" line just above the battery (hot gas solenoid?) is leaking. This 1/4" line comes from the condensate pan (hot gas pan heater) and goes through this solenoid valve and then into the receiver through a service valve.

I tried closing the service valve at the receiver and the rattling noise from the solenoid valve goes away (upon electric motor start up). However, still fails on start and sets a code 10.

Starts on diesel power just fine with no codes!

[cadwaladr]

switch to electric and check you have 12 volts at the plug going to one of the switches,maybe its a power problem,it is going the correct rotation,have you cleaned the condensor while its running on engine soapy water will be as good as anything.

[coldbox173]

switch to electric and check you have 12 volts at the plug going to one of the switches,maybe its a power problem,it is going the correct rotation,have you cleaned the condensor while its running on engine soapy water will be as good as anything.

Got it running on electric now. I started thinking it must be a power issue also. So I confirmed 12v power at the switches. Then I checked the contactor overload. Overload showed "not tripped" but it was tripped. After testing the overload (normally closed) control contacts, tested open. Tapped on it and it freed up and electric motor started. Will install new overload tomorrow.

Now, how long should temp pull down take?
Here are the conditions:
Empty trailer.
I have an insulated false wall up 5' from the evaporator front of trailer (small cooling space).
Ambient temp is 95F.
Target temp is 0F.

Here are my results:
Temp pull down to 18F took 2 hours.... 2 hours for 5' of trailer space?
I shut it down at 18F.

My pressures at 18F:
Low pressure @ service valve above throttle valve = 28 PSI
Low pressure @ port on side of throttle valve = 19 PSI (throttle valve working ok I believe?)
High pressure @ discharge manifold service valve = 265 PSI
Ball at bottom of sight glass and just barely moving. (I never made it to my target temp to see if ball comes up).
Unit has 13lbs R507. (Unit calls for R404 but I have alot of R507 on site and as i understand, its ok to use as it is very similar.)

My thoughts:
Slow pull down caused by damaged or non working power head on TXV?
I see the distributor lines frosting up and when near 20F, all the coil end turns very frosty.
Maybe it just takes a while to come down?? :eek:

[IRMechanik]

Throttling valve pressure should be 20-25 psi below the valve, check it in defrost. The spec for an electric unit may be lower, I can't find a book for a 50 unit. I'm assuming this is not a PE so it has a mechanical throttling valve at the compressor not an etv in the evaporator.
Low suction pressure above the valve could be a plugged screen at the txv inlet.

The 1/4 line you're talking about I think is the bypass check valve, comes off the upper service valve on the receiver. If the valve is leaking past internally it will frost in cool. In heat it will be open to 'dump' receiver. I don't think this has anything to do with your problem, if it were leaking past your suction pressure would be high not low. You can try frontseating the service valve to isolate the valve but it shouldn't make a difference in cool.

[cadwaladr]

5 foot seems a little close to me but you never know i am often wrong!,have you tried disconnecting the high speed solenoid so it just runs on low speed on engine to see how it performs with a slower fan speed? was this machine vacced out before using the gas r507 you may need to tweek the txv but you need to know exactly what your doing,did you clean the condensor?

[coldbox173]

Throttling valve pressure should be 20-25 psi below the valve, check it in defrost. The spec for an electric unit may be lower, I can't find a book for a 50 unit. I'm assuming this is not a PE so it has a mechanical throttling valve at the compressor not an etv in the evaporator.
Low suction pressure above the valve could be a plugged screen at the txv inlet.

The 1/4 line you're talking about I think is the bypass check valve, comes off the upper service valve on the receiver. If the valve is leaking past internally it will frost in cool. In heat it will be open to 'dump' receiver. I don't think this has anything to do with your problem, if it were leaking past your suction pressure would be high not low. You can try frontseating the service valve to isolate the valve but it shouldn't make a difference in cool.

My first thought was a stuck TXV. So I installed a new TXV. I left both screens out (TK tech told me to leave them out). However, I may have heat damaged the powerhead while brazing it in. :confused: I have a new powerhead I was going to install tomorrow.

This unit has a mechanical throttling valve. And I will try frontseating the upper service valve on the receiver tomorrow.

[coldbox173]

5 foot seems a little close to me but you never know i am often wrong!,have you tried disconnecting the high speed solenoid so it just runs on low speed on engine to see how it performs with a slower fan speed? was this machine vacced out before using the gas r507 you may need to tweek the txv but you need to know exactly what your doing,did you clean the condensor?

Ok, I removed the false wall and left it running on electric power when I left for the day. So Ill check it tomorrow and report back.

My process was this:
Recovered all R404.
Changed TXV. (Left out both screens)
Pressure tested with 100psi dry nitrogen.
Vac down to 400 microns and held for 30 minutes. Showed stable.
Charged 13lbs R507.
Cleaned condenser. (was dirty)
Test ran unit.(discovered electric motor power didnt work, so I used diesel untill I fixed the electric motor issue)
I havent tweeked the TXV yet because I never made it down to my target temp of 0F. but I DID open it up couple turns. :cool:

[gravy258]

did you put in R507 TXV ?
you have high head and low suction, the multi temp units are pretty constant on suction pressures i find so on R404a you would have 33psi suction, or 55psi with other zones switched on.
The throttling valves are set on 28psi. You need to have 28psi for capacity.
The ball on the reciever tank should be up all the time with all zones on
Did you set the superheat ? as a base screw the TXV all the way in then out two and a half turns.
The hot gas valves on these units tend to give the problems you describe.

[Kuhltek]

I think it would help to correct throttle valve pressure BEFORE you alter txv

[coldbox173]

did you put in R507 TXV ?
you have high head and low suction, the multi temp units are pretty constant on suction pressures i find so on R404a you would have 33psi suction, or 55psi with other zones switched on.
The throttling valves are set on 28psi. You need to have 28psi for capacity.
The ball on the reciever tank should be up all the time with all zones on
Did you set the superheat ? as a base screw the TXV all the way in then out two and a half turns.
The hot gas valves on these units tend to give the problems you describe.

Ok. I will attempt to set the throttle valve at 28si today. It is currently around 19-20psi. And as I understand, I should check and set superheat AFTER the throttle valve is set. Ill report back my findings.
Thank you!

[coldbox173]

I think it would help to correct throttle valve pressure BEFORE you alter txv

Ok, I will be looking into this today.
I will connect my gauge to the small port on the side of the throttle valve and adjust for 28psi.
Thanks for the heads up!

[Kuhltek]

I think the problems still there your symptoms earlier were saying ball did not float I would normally expect to see it "up" if the tx was restricted but its not always the case and not a "rule of thumb ".take some readings and note down your TD at certain intervals and where the coil temp is in relation to your TD and I think it's possible we could find our answer

[coldbox173]

I think the problems still there your symptoms earlier were saying ball did not float I would normally expect to see it "up" if the tx was restricted but its not always the case and not a "rule of thumb ".take some readings and note down your TD at certain intervals and where the coil temp is in relation to your TD and I think it's possible we could find our answer

On arrival this morning:
Never made my target temp of 0F after letting it run all night with empty trailer. (only running zone 1 for whole trailer)

My multitemp display info:
Current temp 21.8F
AMB T 75.8F
HEAD PRESS 203psi
Ret AIR T 21.7F
DIS.A 15F
TPDF -6.6F
Coil 12.8F
Ball at bottom slightly moving.
Head temp using temp gun 203F

My gauge numbers:
Port on side of throttle valve 15psi
Suction above throttle valve 15.4psi
Discharge manifold 206psi
____
Then I ran a defrost cycle.
Here are my gauge numbers after defrost termination:
Port on side of throttle valve 19psi
Suction above throttle valve 33.5psi
Discharge manifold 235psi
Ball at bottom not moving.
Head temp using temp gun 188F and rising.

My thoughts:
Could I be simply low on refrigerant? I confirmed it has 13lbs of R507. The expansion valve powerhead is good for R404,R502,R507. This trailer has a single remote zone 2 evaporator that does NOT work. The multitemp display doesn't recognize it for some reason (another problem!). :rolleyes:

[Kuhltek]

Get the trailer temp down as low as it has been and cover the condensor to get around 320 dis press and see what the ball does.slowly add some to get ball up to the top then remove cover and let it run it does seem like more gas is reqd so there is only one way to find,also you can't really rely on txv operating correctly if liquid line is not full of liquid so the valve can meter correctly...if the micro is not recognising zone 2 its probably been configured that way for some reason

[clivemtk]

would like to knoww how you arrived at 13lbs of r507 if you read it on serial plate for r404a these two refrigerants differ in all my years working on tk have never seen or heard of r507 being recommended to use

[coldbox173]

would like to knoww how you arrived at 13lbs of r507 if you read it on serial plate for r404a these two refrigerants differ in all my years working on tk have never seen or heard of r507 being recommended to use

This trailer was a basket case before I touched it. The customer had given up on it after several techs attempted to repair it. I asked the customer if I could look at it. I have no experience in these trailers. I usually work on larger commercial drive in freezers and coolers using multiple semi hermetics. These systems run on R507 and I have alot of it around. I may have to start over and use R404 if I have to. I understood that the two refrigerants were very close and shouldnt have an issue so I ran with it. I could be very wrong though!! So upon working on this unit, I weighed in 13lbs of R507 after recovery of unknowns and vac down to 400 microns untill stable. I am still open to grab some R404 as plan B! :)

[coldbox173]

Get the trailer temp down as low as it has been and cover the condensor to get around 320 dis press and see what the ball does.slowly add some to get ball up to the top then remove cover and let it run it does seem like more gas is reqd so there is only one way to find,also you can't really rely on txv operating correctly if liquid line is not full of liquid so the valve can meter correctly...if the micro is not recognising zone 2 its probably been configured that way for some reason

Ok did as you suggested. Covered condensor and maintained around 320psi. Ball was at bottom. Added refrigerant until ball came up to top. Stopped adding. Removed condensor cover and ball came back down to bottom. Ball came up a little and floated in middle then back down and stayed at bottom with slight movement. Confirmed expansion valve 2.5 turns open as a starting point. Coil was very frosty. So I ran a defrost cycle for a fresh new test. After defrost and let pressures stabilize and let run for 1 hour, here are my new numbers:

My multitemp display info:
Current temp 17.8F
AMB T 88.5F
HEAD PRESS 281 psi
Ret AIR T 17.8F
DIS.A 8.3F
TPDF -9.4F
Coil 8.6F
Ball at bottom slightly moving.
Head temp using temp gun 226F

My gauge numbers:
Port on side of throttle valve 19psi
Suction above throttle valve 30.7psi
Discharge manifold 289psi
____




The numbers 1 HOUR LATER:


My multitemp display info:
Current temp 15.7F
AMB T 88.3F
HEAD PRESS 279psi
Ret AIR T 15.6F
DIS.A 6.2F
TPDF -9.3F
Coil 4.1F
Ball at bottom slightly moving.
Head temp using temp gun 210F

My gauge numbers:
Port on side of throttle valve 18psi
Suction above throttle valve 28psi
Discharge manifold 285psi
____
Then I ran a defrost cycle.
Here are my gauge numbers after defrost termination:
Port on side of throttle valve 18psi
Suction above throttle valve 50psi
Discharge manifold 284psi
Ball dancing about 25% from bottom.
Head temp using temp gun 184F and rising.

[coldbox173]

Quick update, unit seems to be running ok. It currently has product in and running between -5F and 15F. However the ball is at the bottom and slightly moving. Hmmmm, may need a little more refrigerant possibly?