Mechanical Thermostat Selection

[mr slim]

Hi Guys

A friend asked me to look at his stainless steel multi deck dairy display fridge.
Its operating on R22 and I cant find a name plate on it anywhere.
Anyway he says the temperature is cold one day then warm the next so i suggested replacing the thermostat.
Its a mechanical type thermostat but i dont know which type of thermostat to get for it.
Would a danfoss n0.8 or ranco VB-7 do the job?

Any help appreciated

[install monkey]

display fridge on r22- u sure?

[install monkey]

might just need a service- finned evap or plate?

[frank]

have you tried bypassing the thermostat to see if it cools OK?

[mr slim]

Its a finned evap with 2 evap fans.
Cleaned fan blades and evap coil is clear.
It cooled down to 4 c when i was there today so I know it cools ok.
The off cycle defrost timer is working so i dont think it is that.
I must admit i was shocked to see a display fridge on R22 but thats what the stickers say on the comp and inside the compressor compartment.
With my friend saying it that the temp control is eratic my thoughts were to change the thermostat for a start but im not sure which type would be best.

[install monkey]

either fit or hide a digistat - eliwell 901 or equivelent that just cycles compressor signal as defrost is via the off delay- sensor is easier to locate on return air and u can calibrate it,and set ur diff to about 3 deg with a 3 min start delay- if u fit a 10 quid domestic stat then ur gonna struggle as they fit onto the evap plate and cut out at -8 deg and u could fit 3 before u get it sorted

[mr slim]

Thanks for your reply install monkey.
I was going to fit an ID Chill because i know there is a lot of messing around involved to calibrate it to cut in and out at the right temp but was wondering if anyone knew a certain type or brand of thermostat suitable for these cabinets.

[Tayters]

Seen the timeclocks stick intermitantly - the type with the pegs round the outside. Not saying yours is goosed mind, just putting my two pennies in.

Oh, seen a display chiller with a remote R22 condensor as well. Didn't work mind - compressor seized!

[Andy AC]

Earlier on this year I put one of those prodigy f2000 stats in as a temporary replacement on a brand new arneg with a faulty stat. It worked better than the eventual proper replacement part which turned up about a month later.