- This topic has 18 replies, 3 voices, and was last updated 8 years, 5 months ago by
.
-
Posts
-
Hello, my tough old 7844P fills, rinses fine. It then fills for the wash cycle, starts running but does not heat the water or advance through the cycle, it will just sit there running.
I have checked the large ribbon cable that is continually flexed at the bottom of the door and has been the source of all breakdowns prior to this but all the wires are fine.
I will get the washer into my garage so I can get under it to check if power is actually getting to the water heater.
I am a DIY fixer and always willing to learn.
My questions are.
1. will the machine only advance through the wash cycle if the water actually heats up?
2. could someone give me sequence of things to check.thanks in advance, Tom.
Re: Hotpoint 7844P cold and stuck mid wash
tiger750 wrote:My questions are.
1. will the machine only advance through the wash cycle if the water actually heats up?Yes.
tiger750 wrote:2. could someone give me sequence of things to check.
1) Double, treble check, the heater wire not broken in wiring harness near the hinge. That is THE most likely.
2) Check the stat connected to the heater, all contacts should be closed?
3) Burnt out heater switch contact in the timer?
4) The heater faulty?
Re: Hotpoint 7844P cold and stuck mid wash
Hi again, thanks for advice.
Double checked the wiring, waggled the wires with a multimeter one each one seperately, they were all fine.
A few questions before I proceed…
1. With this being an old machine am I right thinking it does not have an in line water heater, I cant see one. So is the water heating done by the element inside the dishwasher at the bottom inside the washing area? I originally thought this was just a heater to dry things off at the end. Or is there a water heater hidden in the sump/pump area? I can’t see any extra wiring disappearing into thoses areas so I presume not.
2. I have checked the resistance of this element inside the washing area it seems to be around 20 ohms, is that about right, if my maths is correct that equates to a draw of 12amps and around 2.8kw so that seem about right?
3. Again I am presuming the thremostats are the obects underneath the the heating element and also act as attachment points, there are two, again I presume one is 50deg and the other 65deg, they are both closed at room temp, so again ok?
4. There are two other objects screwed into two brass pins welded to the bottom of the ‘tub’ what are these?
Re: Hotpoint 7844P cold and stuck mid wash
Update….I may have made a significant discovery.
There is a thick grey wire that connects one of the termostats to the timer. Can’t really work ont if it is a suuply or return. The plastic shroud around the spade connector was melted and the spade connector blackened. Maybe the last time I fixed a wiring fault I somehow him not make a good connection there and the added resistance caused it to overheat? I have cleaned the connection up and made a good connection but still the fault persists.
The spade connector coming out of the timer is a bit more wobbly than the other connection, the heat seems to have lossened it slightly so maybe it is damaged in the switch, it seems impossible to get into the switch assembly?
I have put my ohmeter on what Look like the feeds to the timer to see if they connect to this damaged pin as the timer is turned by hand, no connection is made.
Thinking I may have a damaged pin/switch, wish I had a wiring diagram so I could check the timer out, really don’t want to scrap this great machine becuase of I switch!!
Re: Hotpoint 7844P cold and stuck mid wash
Sadly the control timer has been obsolete for several years now. 🙁
Re: Hotpoint 7844P cold and stuck mid wash
Ah I see my suspect #3 is the problem. Yes indeed the timers have been obsolete for years but I recall some timer and module repair companies might just be able to help with a replacement? Not certain though, I’m going back a bit since I last checked. Oh and eBay of course.
Re: Hotpoint 7844P cold and stuck mid wash
Had to dig out my old ‘hard copy’ of the manual from 1995. 😯
The original part number is 1800120, might help in finding one, although I know that EMW don’t do dishwasher timers. It doesn’t look as though QER do either. 🙁
A quick Google doesn’t throw anything up.
Re: Hotpoint 7844P cold and stuck mid wash
I’m pretty sure the timer is the problem.
You won’t belive this but i think i have found one online!
£19.99, it’s an AKO 514 693 from casaparts.
Could anyone out there give me a few checks to do ie. which pins on the timer should connect to the suspect pin ( thick grey wire that connects to one side of the heater ) before I order.
Could someone also confirm that this element in the washing area also heats the water as well as dry the dishes.
Re: Hotpoint 7844P cold and stuck mid wash
There is only one heater in the machine.
Three are seven different, non interchangeable timers listed for the 7800 model range and the AKO numbers on the side are not given in the manual. Unless it is in a box with 1800120 on it, or your timer has the same AKO number on it then the chances are it will not work.
If the terminal is a bad as you suggest then knowing the internal connections of the timer will be of little use, however the heater is switched via 4 & 4b
Apart from the timer motor or the timer drive cams failing the heater contacts burning out was the only other reason we ever changed these timers, and that wasn’t often.
Re: Hotpoint 7844P cold and stuck mid wash
My timer has AKO 514693 stamped on it and the one at casaparts is listed with the exact same part number, hopefully it will be the same? I’ll double check the connection you suggested and get back.
Re: Hotpoint 7844P cold and stuck mid wash
If it has that AKO number on it then you have just got very lucky indeed. 8)
Re: Hotpoint 7844P cold and stuck mid wash
That Casaparts timer defo worth a punt. It’s secondhand true enough but the pins look sound, not burnt. Assuming it is still in stock go for it!
Re: Hotpoint 7844P cold and stuck mid wash
OK chaps. Timer has arrived and is fitted.
Machine fills, does pre-wash and moves to heated wash, water now gets hot!!!!! So that is progress, unfortunately the thick grey wire whose terminal got overheated on the previous timer started to get warm and then got hot to a point I was uncomfortable with so I stopped the machine.
So I have now got to work out why this wire is getting hot. It goes from the timer to one side of one of the thermostats, the other side of the thermostat goes to the heater element.
I have measured the resistance of the wire—0.5ohm this seems ok?
Resistance of the Heating element id 20ohms, is this about right, it equates to a current of 12amps so I’m thinking that is fine?
Is it normal for a wire so heat up with 12amps passing through it? The cable is thicker than most of the others so it is designed to carry more current.
quite baffling!
Re: Hotpoint 7844P cold and stuck mid wash
Heat is usually a sign of loose or poor contacts, I believe this is a used timer and where the heat is is normally where the problem is as well. 🙁
What is the condition of the AMP tag like, might be worth replacing that.
- You must be logged in to reply to this topic.