Eliwell 901 Controller Parameters

[Northdude]

Can anybody tell me what these parameters are for this controller as I have a dairy cabinet with a remote condensor and the evap coil keeps icing up so I need to check defrost settings but cannot translate the codes. Here are the parameters and readings.

CP-dif(2) odo(0) dbl(0)
FPR-ul(N) dl(N)
CNF-hoo(1) tab(325) rel(19)
DIS-loc(N)
PA1(1)
CA1(1)
DRO(0)
If anybody can tell me which of these relate to defrost that will be great.Thanks

[nike123]

What Elywell do you have? WM, EWPC, IC ......

It looks like IC901 which is simple thermostat without defrost control!

[Northdude]

sorry its an ic 901, i have managed 2 find a parameter data sheet on the net but none of the parameters on the controller are for defrost??? Could it be possible that these controllers do not have a defrost on them?? I am slightly baffled by this, any ideas?

[Andy_CTC_Ref]

Eliwell IC 901 controllers dont have a defrost cycle built into them, then just controll temp.

[Andy_CTC_Ref]

Forgot to say, change it for either an ID 961 or ID 971.

[nike123]

sorry its an ic 901, i have managed 2 find a parameter data sheet on the net but none of the parameters on the controller are for defrost??? Could it be possible that these controllers do not have a defrost on them?? I am slightly baffled by this, any ideas?

Try to find mechanical/electronic defrost timer inside control board!
Or it doesn't need defrosting at all. If that is the case, fans should work all the time!

[Andy_CTC_Ref]

Try to find mechanical/electronic defrost timer inside control board!

Nike123, you beat me to it! haha. was just about to sujest the same as that controller has prob been in place a few years??? and the icing up is a new problem??

[Northdude]

bit stumped why its icing up then, all evap fans working ok, solenoid closing and unit pumping down ok.hmm

[Andy_CTC_Ref]

bit stumped why its icing up then, all evap fans working ok, solenoid closing and unit pumping down ok.hmm

Unit will still pump down when it cuts out at it set point, the soleniod valve will be controlled via the controller and evap fans prob have constant live feed if its a off cycle defrost (no heaters in evap) if theres a time clock in the panel then the fans and heaters are normally controlled via time clock.

[nike123]

bit stumped why its icing up then, all evap fans working ok, solenoid closing and unit pumping down ok.hmm

If system doesnt have defrost heaters or other kind of defrosting, make audit of system temperatures and pressures!
You know, usual stuff: Superheat, subcooling, pressures, air temperatures at evaporator. Check for fresh air entering, product loading and storage conditions. Correct amount of air at evaporator etc...

[Northdude]

thanks 4 your help, i have located a defrost timer which appears 2 work but not sure if the clock is ticking so goin 2 leave it for a half hour and see if it moves, there are no heaters the timer just cuts the supply to the solenoid and the fans run contantly.

[Andy_CTC_Ref]

Most likey the timer then matey.
let us know how you get on.

Andy

[Northdude]

thanks andy, checked the timer and it appears to be working correctly, the defrost was set to 10 mins 4 times a day so i have increased the times but dont think that is the solution as the cabinet has been in for a few year and icing up hasnt been an issue.so i am a bit puzzled as everything else appears to be ok

[Andy_CTC_Ref]

You say its a dairy cabinet, as in a dairy display cabinet???

If so It may be a few things.

Ambient temp is lower in the shop due to it being winter,so defrost cycle isnt as efficient as it should be at clearing the evap?? increase the defrost lenth to 20 or 30 mins?? most walk in chillers that i work on with off cycle defrost are for 30 mins.

how is the air flow on the unit?? is it creating a suffient air curtain?? does it have a honeycomb type mesh at the top of the cabinet?? take this out a check its not clogged with years of dirt. if this is blocked then the evap will ice up as it will not have the correct air flow over the evap.

check the set point on the controller, id say no lower than +2 oC, any lower then ice will start forming. i normally set at +3oC with a 2oC diff. temp will range between 3 and 5 then.

[Andy_CTC_Ref]

Also check theres enough refrigerant in the system?

Check the unit has the RIGHT refrigerant in it!
I had a call out to a walk in chiller last year, as the current contractor could fix it. the unit kept icing up! i found that it was a 404a condensing unit with 404a refrigerant in it but working on a 134a expansion valve! changed the expansion valve to the correct one, and its been fine ever since.

[nike123]

If you want to practice posting than this is not place for that.

Be patient!

[paddyaircon]

get a id974

[Brian_UK]

get a id974

I think you are about twelve months too late with that suggestion.

[cadwaladr]

check the location of the probe,check or replace the probe ,calibrate the probe,widen that diff to 3/4 degrees maybe extend the defrost timer every 4 hours ,and defrost duration to 30 mins,calibrate it first!