Samsung american fridge freezer problems RS21 fridge defrost problem and RSH1 fridge icing problem

The following info concerns the RS21 fridge defrosting problems and the icing up of the top left vent on the RSH1 RSJ1 fridge cabinets. There is video help available further down the page for both problems.


There are several reasons why the RS21 units cause fridge defrosting problems. This guide is intended to help you unravel what is wrong and what you need to fix the fridge problem. It is only going to deal with specific components within the fridge cabinet, it will not cover refrigeration gas systems at all. However, if your freezer is also icing up as well as the common fridge problems, this must be investigated seperately, fixing the fridge components will not cure the freezer.

This applies to RS21 SRS2026 SRS2028 and SRS2029 fridge sections

A common indicator is that the temp readings on the door display do not alter, yet the unit has turned off. Several components can indicate the same error symptoms therefore it is important to check out all the relevant components at the same time. Another common failure is a whirring noise from the unit, which stops as the fridge door is opened. Yet another is the unit works for 12 hours (approx) then defrosts.

Within the RS21 fridge section, behind the water bottle and the back panel is an evaporator, this is the system part that is absorbing heat from the unit and food products. Whilst the cabinet is frost free the evaporator isn't; it gradually builds a covering of frost/ice as heat and moisture is removed from the air within the fridge section. If left to build ice, it eventually restricts the air flow, blocks the drain hole of the cabinet, penetrates the insulation of the back panel, blocks the fan drain hole which stops the fan running or creates noise as the ice surrounds the fan blade, freezes the cool water bottle, sometimes splitting it and prevents the fridge section from working correctly. 

There are reasons for this happening, one of which could be the gas system is not 100% correct. In our experience this is the least likely cause of fridge failure, but also the one where specialist knowledge, training and equipment would be needed. It is worth noting that the freezer section should also be problematic, should the gas system be the cause of failure. The freezer could be, not cold enough, cold only at the bottom and warm at the top, icing only the top part of the evaporator coils, these conditions point to a shortage of refrigerant or inefficient compressor. So best left alone other than to say if the following guide to the components proves them to ALL be ok, it should then become a consideration, as should a defective PCB control component.

The defrost components

To keep the ice build up in check the unit goes into defrost mode, you will be unaware of this happening, the programme is built into the electronic control and cycles almost silently until it goes wrong. There are 2 defrost heaters, 1 defrost sensor and a protecting thermostat (TOC) involved in defrosting the evaporator. One heater fixed into the vanes of the evaporator keeps the evaporator clear of excessive ice build up, as that ice melts the tray heater ensures the water runs out of the cabinet via the drain hole. Please note, that if this water was to re freeze and remain in the cabinet the next defrost cycle will add more water and then ice to the problem. It is very important that both heaters are fully functional. To control the heaters the defrost sensor monitors the rise in temperature during the defrost cycle, the electronics responds to the rising temperature to switch the heaters off. There is a protection device which is a "one shot" safety fuse. It is strapped to the refrigeration tube of the evaporator and will respond to any overheating by the elements during the defrost cycle, once tripped it disables the heaters until service investigation discovers it.

Failure of one or more of these can lead to the insulation of the back panel becoming saturated with water/ice and in turn causing fan problems. The back panels already have a drain hole for water to exit the cabinet and prevent build up of ice around the fan, defrosting the fan has been a problem area for these units for some time. There is a modified back panel that transfers heat from the evaporator defrost heater to the drain hole area during defrost cycling. 

Testing the components

Before any testing is carried out the unit should be

1) Switched off and the plug removed from the wall socket. Under no circumstances is "live" testing required to ascertain the electrical standing of the following components.

2) Defrost the fridge fully before you start

Typical scenario when the defrost cycle goes wrong

Removing the shelves and water bottle gives access to the screws holding the back panel in place. There is a sealing strip around the back panel, if you try to remove without defrosting you can damage this seal. Damaging the seal will affect the air flow and cause over icing on the evaporator. Hand held steam guns are ideal for quick defrosting, but care should be taken to avoid damage to plastics and components within the fridge. We have seen damage to cabinet liners where huge wallpaper steamers have been used to quickly defrost the ice away, this will cause insulation failure of the cabinet so don't use them!

Once you have the back panel removed the following readings can be obtained using a multimeter.

go to youtube video guides for testing samsung defrost components

Defrost sensor: this has been modified and if yours is a white coloured bullet sensor head you should replace it with the latest one, which is black. The white ones are known to ingress moisture with the contraction and expansion of the plastic head unit, causing defrost problems. This link is a youtube video on testing the defrost sensor The sensor reacts to heat very quickly. If you don't get these readings at these temperatures the sensor should be considered faulty.

Evaporater Defrost element: this has to be isolated from the tray heater plug, testing it connected to the tray heater will result in an incorrect reading. Once isolated it should read 485ohms, we have recorded these at 200 ohms and to earth, so its 485ohms or very close to it for the heater to pass the test. Here is a youtube vieo on testing the defrost element

Tray heater: this is self adhesive and stuck in place, isolated from the other heater it should read 2.1Kohms. if it does it's ok, check for shorts to earth as well. Watch a video on how to test the tray heater, just click the link.

TOC thermal fuse: strapped to the refrigerant tube of the evaporator this should have electrical continuity, usually less than 0.1 ohms, don't forget to measure the resistance of your leads and deduct that reading from the final reading. Check out testing the thermal fuse on youtube.

A correctly positioned thermal fuse

If any of the above components is faulty you need to replace them. If the insulation of the back panel is shot because of ingress of moisture you need to replace it. If you just defrost and replace a faulty panel you'll be doing it every 3 to 4 weeks, it all only works if all the components are good. 

The fridge back panel

Also known as the evaporater cover, is a very important part of the fridge. It has a seal around it that stops incoming air from causing ice build up on the evaporater. When removing it, care should be taken to not damage the felt seals. The back panel has a fan motor mounted on it, this is for circulating the air around the fridge compartment, if it gets restricted by ice build up the whole defrost cycle will be affected. Symptoms of this are a noisy fridge, the noise stops as the door is opened, thats because the fan is switched off whilst the fridge door is opened. The insulation of the back panel gets damaged by water ingress, once water logged the whole thing freezes up, the insulation swells and everything goes wrong. The only cure is a new back panel, enlarging drain holes will not work in the long term.

The replacement back panel has been modified with a heat transfer plate and clip, which allows heat from the evap heater to warm the drain hole of the fan motor during the defrost cycle. This mod comes with instructions on how to fit the evaporator clip into place. There are different back panels depending on which RS21 SRS2026 SRS2028 or SRS2029 you have, the  RS21J and RS21K coolzone models have a different back panel to the RS21 SRS2026, SRS2028 or SRS2029 models without coolzone.

The 1st letter after the model number denotes which back panel is required The RS21 J and K models are the coolzone ones, any other letter is the standard twin cooling panel, as an example the RS21DCNS is this back panel

The water bottle can crack or split as a result of being frozen by the faulty evaporater and the defrost problems, check it for leaks.

Finally, before you rebuild the fridge section, just check using a small cup of water that the drain hole and channel through the cabinet are clear. About 4 inches down the drain channel takes an approx 90 degree bend, we have found this bend blocked with ice, the hand held steamer soon clears it. Left blocked the ice problem soon returns.

Need more help; telephone 01709 525978 (between 1400 and 1600) and talk to an engineer and the author of this information.

All of the components can be bought seperately, but many customers have bought all 5 components as a repair kit. Here is a link to it in our shop, RS21 5 part defrost kit this is the normal kit and not the coolzone (RS21J & RS21K) one.

It fits the following models:


and the following Samsung model codes: 
SRS2028C, SRS2028DVW, SRS2028CVW, SRS2028CSS, SRS2028, SRS2028FSS LAS, SRS2028FSM

** Just a note regarding reliabilty of these parts, if fitted correctly our experience shows that the replacement parts are very reliable and over the last 2 years only a handful of heaters have failed within 18 months of replacement. **


Samsung RSH1 RSJ1 fridge icing problem

The RSH1 fridge suffers from the top left hand vent icing over, causing poor air circulation in the fridge. There is a modication kit available to sort this out. Fitting it is easy enough, the video will explain what and how to do it. It involves moving the location of the defrost sensor (new sensor and securing clip are in the kit), adding a couple of packing pieces to the back panel, repairing the damaged foam (not always possible due to the extent of the damage) and altering the defrost temperature setting. All of this is covered by the video.

It may be that a new back panel is required because of water ingress damage to the existing panel, just like the RS21's there are different fridge back panels, all are available. If you're not sure which you need, we can help. here is a link to the back panels in our shop and this link will take you to the RSH1 RSJ1 defrost modification kit

All of this is straight forward to do, don't buy a back panel if you do not need one, if you need both back panel and modification kit, the link will take you to it in our shop. Appreciate your votes on our video and our youtube channel is called ukanfixit

Here is a video regarding the defrost heater fitted to the RSH1 and RSJ1 cabinets, if you can test yours and its ok........ don't buy a new one.