[ls007]

I have a 1.5 years old Kenmore dryer which shuts down mid cycle with error code F70. Does anyone know what the error code mean? It seems to be an overheating issue to me. I have tried vacuuming the lint off but hasn't helped.

[denman]

I cannot find info on this specific error code but a search for it on the web using Google brings up a mess of others with the same problem. Some say it is a board/communication problem, others a temp sense problem.

You could try the following

Undo the dryer from the exhaust
Run a load
If the load dries correctly then you have a vent problem.
Clean/check the vent system. Make sure the outside louvers open fully.

If you do not want lint in the house.
Take a pair of pantyhose, put one leg into the other and attach this to the dryer exhaust.
Leave enough room behind the dryer so it can blow out like a windsock.
Run a load.

Both the above will allow you to check the air flow and temp.
Also the above is NOT recommended for a gas dryer due to possible carbon monoxide problems.

[ls007]

There have been many different suggestions about the cause and some work on my side to diagnose and fix the issue. First the causes:
Reply from Repair ************ repair guru:
Dear Madam/Sir,

Thank you for your recent inquiry, regarding your 2008 Kenmore Dryer, model: 11087872602.
F70 = Overheating sensed causing dryer stop until temperature reaches(drops) below set level - determined by manufacturer

Can be caused by different contributing factors;

1. poor airflow

2. blocked air flow screen inside tumbler

3. clogged lint screen

4. slow tumbler (low revolutions)

NOTE;

Ironically, the fourth factor has been lurking behind the popular discussions on this problem that has exhibited itself on both the whirlpool and Kenmore products with the main triage to have included inspection of the electrical connections made by the installer.

These electrical connections not followed properly with accordance to '4prong' NEMA 14-30R (30amp, 2-phase circuit outlet) with separate ground and neutral posts, as exhibited in the standard dryer installation manual, will cause your tumbler to run slow. Hence, the 4th factor which caused the 'F70' code stops the dryer from operating.

Now, you have corrected the wiring as necessary and eagerly place some stuff's in there and all seems well. But as soon as you place something large and wet (HEAVY/BUNDLE), you get the error code again, you thought you had it!

Okay, this is what you need to do;

1. make sure your air flow is adequate by really cleaning the duct (I stuck my hand through the wall duct and scraped off old hard lint that can collect humidity & even cut my finger). Also make sure your vent hose does not have any unnecessary elbows or squiggles in it ( I had an elbow/pan type and it is not good as the heat seems to reflect too much ). KEEP IT AS SHORT AS POSSIBLE - I KNOW IT'S HARD, BUT IT IS NECESSARY.

2. Refrain from using too many softener sheets as they can & will restrict the air flow screen inside the tumbler.

3. Make sure your lint screen is clean - wash it periodically as lint particles collect moisture and this in turn raised humidity.

4. Once you have verified your electrical connections as stated earlier in this posting, run a normal cycle with towels or something of the like so as to reset the sensors in the dryer.
.

THE MAIN THING TO REMEMBER IS THAT 'F70' SEEMS TO BE THERE TO PROTECT AGAINST OVERHEATING WHICH IN TURN CAN TURN TO A FIRE HAZARD!

The tech sheet kindly provided by a member on another forum shows F70 as a control board issue as noted in this thread.

So what did I do so far:
Opened the top and back panel and thoroughly cleaned the lint. I did not however ,think that the lint was excessive as to cause motor malfunction. I also unhooked the dryer from exhaust and ran three loads and they all dreed without the error. Now it is possible that removal of lint did the trick but it looks like the venting issue as suggested in one of the replies has some credence. next I will hook the dryer back to wall exhaust and run a few loads. if the error returns I will focus on venting.
The main question that I am asking myself is that if the control boards are at the heat of issue would it possible to do any loads without the error. Your comments and suggestions are very welcome.
I hope all this works ends up in a running dryer and helps other people struggling with the same problem.

[denman]

The main question that I am asking myself is that if the control boards are at the heat of issue would it possible to do any loads without the error.
If it runs good without a vent connection then the board is doing it's job. It could be that the amount of variance from the ideal is a little narrow but this seems to be part of the design so you cannot do anything about it.
This is better than the unit over heating and blowing an over temperature fuse.

I hope all this works ends up in a running dryer.
It sounds like you already have a running dryer though you may have to sort out some venting problems.

[ls007]

Denman
Thanks for your helpful replies. So it seems I have narrowed it down to venting issue with your help. Could you suggest how to go about fixing the venting issue rationally.

[denman]

A lot depends on where it vents to.

Make sure the vent diameter meets your install spec.
Give it a good cleaning and check that the outside louvers open fully.
The best way to clean it is take it apart, then you are sure that it is clear. This also allows you to see if lint is collecting at a certain point in the system.
I am not a fan of flexi plastic pipes. They tend to hold lint and can be a fire hazard.
Metal flexi pipe is somewhat better but I try to keep it to a minimum.
The best is metal vent/duct pipes but this is not always possible all the way to the dryer.
Keep the number of turns to a minimum.