Thermostats on INDESIT ISL70C Dryer

[StepByStep]

Thanks for all the helpful info and advice on these forums.

My Indesit ISL70C drier was working fine except for one thing… overheating the clothes -shrinking cotton shirts etc ‘:cry:’.

I checked the 3 thermostats inside the heater cover. There’s continuity across the two stats either side of the middle one… there’s no continuity across the middle stat.

I’ve four questions…

1. Is this the correct way to test these thermostats?

2. Can I get a generic thermostat somewhere? (Preferably one that can be reset if it trips).

3. I accidentally damaged the thin asbestos-like wafer heatshield over the heater elements. It’s intact but probably won’t sit tight with an airflow past it. (I don’t know of any high-temp tape that would hold it in place). Where can I get a replacement?

4. Black powder spilled from the small cover over the drum shaft-end. Is this some type of lubricant? There’s very little left….

I’d really appreciate some help. Thanks… ‘:)’

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

The black powder is actually the drum shaft and rear bearing wearing away. If it hasn’t already the drum shaft will soon snap and cause the drum to drop, possibly snapping the belt.

One of the three ‘stats’ is actually an NTC.

You should under no circumstances attempt to fit a generic or resettable stat. Your house insurance will not pay out if you burn your house down as a result. :rolls:

If the heater shields are damaged then you would be well advised to fit a new heater assembly which comes complete with stats etc.

Three different heaters, full serial number needed to identify.

Sounds like you also need a drum shaft & seal kit as well.

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

Thanks Iadom.

Serial Number is probably 30619 (white paper label on back)

STATS
Does continuity test show if failed?
To make decision about replacing the whole heater assembly I just need to know the cost for parts…. (stats + NTC + heatshield) Vs assembly… . The heaters themselves are ok.
Point taken about generic stat.

SHAFT
How difficult is removing the bearing? Can drum’s weight be supported or does it have to be dropped down to work on the shaft & bearing?
With the bearing off will examine the shaft for wear. Do you sell bearing/seal kit?

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

Serial number is a nine digit number, should be inside the door. The number you have given is the commercial code.

You can test the two stats for basic continuity in the ohms range but you really need to do a resistance test in kohms to check the NTC.

The heatshield is not available as a separate part.

Four different heater assemblies, not three 😳 . Three of them are around £37 ex vat, the other one is over £54 ex vat.

Stat kits ( two different ones ) are around £23 ex vat.

Bearing and seal kit is available in the shop , HERE

Just about possible to change the drum shaft without removing the drum but to do the job correctly the drum needs to come out to allow you to fit the new seals.

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

Just a quick post…

Thanks Iadom,

Serial no. is 506241111

Will check resistance KOhms across NTC tonight 🙂

NTC markings are ELTH, Type 279, T175,
Printed on side is 13-05 / and either 0400 or else 0070 (upside down)

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

Stat kit is C00308298, heater assy is C00258828. It is not the expensive heater so complete kit inc stats & ntc is only £14 or £15 more than stat kit alone.

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

iadom wrote:
You can test the two stats for basic continuity in the ohms range but you really need to do a resistance test in kohms to check the NTC.

Thanks Iadom,

I want to confirm, has the NTC failed?
The NTC is ELTH T175, Type 279. Side marking are 13-05, 0070
The resistance across it is 700 K-Ohms when tested. What should it be?

It seems the 2 stats are fine because there’s no resistance across them.
ELTH T175K, 16(3)/250, Type 261/P. Side Markings are 19-05, 1488
ELTH T175K, 16(3)/250, Type 261 PB, Side Marking are 17-05, 2235

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

StepByStep wrote:
The NTC is ELTH T175, Type 279. Side marking are 13-05, 0070
The resistance across it is 700 K-Ohms when tested. What should it be?

If it was quite cool then thats about right. Just pulled one out of the car to test.

Put it against a radiator for a couple of minutes and it went down to around 230 k-ohms. Popped it in the freezer for 15 seconds and it went up to over 1000 k-ohms.

Do that simple test yourself to verify that the thermistor is functioning correctly, they don’t often fail TBH.

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

iadom wrote:

Put it against a radiator for a couple of minutes and it went down to around 230 k-ohms. Popped it in the freezer for 15 seconds and it went up to over 1000 k-ohms.

Do that simple test yourself to verify that the thermistor is functioning correctly, they don’t often fail TBH.

Iadom,

NTC must be fine! :rolls: it’s jumped through all the hoops. 😆
On radiator it gave about 240 k-ohms, freezer for 20 seconds and it gave just over 1000 k-ohms

Thanks again for help

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

By the way, removed all fluff from machine,

there was no large buildup anyway.

I keep it clean regularly, both filter and condenser. So why it shrinks my shirts ❓

My dress sense is not THAT bad 8) and it has a good home…

Since NTC tests ok, has a stat failed? Does a stat usually fail-open (no current can pass), and assumed to be ok if there’s continuity?

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

Has it only just started doing this, have you dried the same shirts, on the same setting before?

Is the copper braided brush in good contact with the top of the drum and is the band around the drum in place with all of the thin black plastic strips in place.
Is the small earth strip behind the square cap at the back making good contact with the end of the drum shaft?

A high heat setting for too long is the only thing I can think of TBH.

Try doing the shirts on a timed dry.

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

Just remembering now, Iadom, actually, 💡 machine was too hot since I bought it secondhand a year ago. I’d got so used to it 😯 that I’d actually forgotten. Worked fine in some regards, ie I could dry my clothes nicely, but programs were all much too hot.

So I’ve used the same program, the lowest temp one (for Special/Sport fabrics) since then (for my cottons!). Recently that too seemed too hot. Now that I remember this again, those programs were for cotton (programs 1,2,3) and synthetics (programs 4,5,6). There’s no way they should be so hot.

No error light or anything by the way, they seem ok.

Just examined the copper brush now. Looks fine Iadom. No thin black plastic strips visible, but band around drum sits on top of a wider clear plastic strip (very thin material) that also looks fine.

Earth strip was making VERY POOR CONTACT with the drum shaft with all the black powder and oily gunk coating it ❗

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

The rear earthing strip has to be in good contact with the drum shaft.

[StepByStep]

Re: Thermostats on INDESIT ISL70C Dryer

………………………………………..

BEARING: Looking at the machine I realize some tips on the sequence for dismantling/reassembling would be most helpful.

Iadom, on the link you posted above there’s what looks like some seals or something included with the shaft kit. What are these?

I contacted Indesit who say that the bearing for my machine may be either teardrop or rectangular shape. Have to dismantle and see what’s fitted.

………………………………………..

TEMP: Ok… Progress! With the top removed from the dryer another NTC was visible at the front of the machine. Removed it to test it and saw the space below was packed with fluff. Bingo! Certainly it was giving a wrong reading because of this.

It’s fitted into the top of door surround. There’s a very small grille there, which I’d never even noticed before! It was full of fluff. Needless to say it’ll be clean from now on. The NTC itself tested fine, I think, similar to the other one. The readings I got (if anyone can confirm them) are:

Type 279, T175, Side Markings: 19-05, 0069 (or possibly 0065)
At room temp, 500K-ohm
On radiator, 260 k-ohm
1,400 k-ohm after being in freezer for 15 seconds.

Hopefully that’ll remedy the temp problem.

……………………………………………

Have cleaned earth strap,etc. Just need new shaft/bearing to try it out 🙂

……………………………………………

Thanks, StepByStep

[iadom]

Re: Thermostats on INDESIT ISL70C Dryer

The shaft and seal kit includes both types of rear bearing together with new front and rear seals. The fact that you have fluff all over the place suggests it would be wise to change these at the same time. A fiddly job removing all the old adhesive from the original seals but worth it in the long run.

In the kit will also be a thick washer, you should add this to the one that will already be on the drum shaft between the drum and the back of the machine.

We can’t really go into ‘blow by blow’ details of strip down, sides off, front console and panel released, drum out will make changing the drum shaft and the seals easier, you just have to follow your nose really. Getting it back together is the fun bit. 😉

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