Help with print relais /PCB board

[billi]

Hi

The Macerating System in our Bath is not working automatic any more  (only  switch on and of  by hand at the socket )

So i think it is the relay   ,

Do i have to find the exactly matching relay ( i understand the pins on the back should be the same ) , but in relation to Volt and Amps

Or could i use the one on the bottom of the picture (its 48 volt  not 24 Volt ) ?

Thanks Billi

[wyleu]

Nope you should use 24V part, it would be pretty marginal that the 48V part would pull in.

That resistor looks fairly fried as well...

A relay is pretty simple it's volts across ohms on the input side and current and contacts on the output side. So a like for like should work electrically. Physically it pays to replace an on board component with similar. It avoids straggling leads and other areas of weakness cos you have to solder wires to boards and any movement will work the solder joint.

One other thing there might be a diode strapped across the coil. It would appear on the diagram if there was, but it's always good to remember the possibility.

Interesting to see the different handling characteristics for AC and DC. 

[Baz]

.....and the transistor that is probably the relay driver. Also check the little plastic pipe to the switch isn't just bunged up with soap scum. ( a common washing machine problem)

[breezy]

Not only that, but the contacts of the suspect relay are rated at 15A DC, and the replacement is only rated at 5A DC.....

[breezy]

Hmmm.

Don't seem to be able to edit my previous..

Looks like I misread the markings. According to the datasheet, the NC contacts are rated at 10A for AC, and the NC contacts for 6A. No DC ratings are given. In ny event I may have misunderstood the original question - is the macerator motor low-voltage DC? I assumed it was as it's in a bathroom...

http://www.farnell.com/datasheets/13797.pdf

[Baz]

And the 48v coil won't turn on in a 24v system.

[billi]

Ok thanks 

I tried to get a whole replacement board  , from the manufacturer , but off course the idjets  , want me to sent the whole unit back to repair  and wont sell me the PCB board  only

They advices me to use a hair-dryer for 10 minutes  to heat up the board  and this did the job a few times , but now game over

Here again the details written on the  relay  so is the one Breezy attached the right one 


or here  i think  i am right


Thanks

[davebodger]

Billi,
     how about this one from Farnell - pin-out, size and coil resistance is virtually identical.

I think it's a very common relay - I used one to replace a faulty relay in my wireless room thermostat.


http://www.farnell.com/datasheets/56340.pdf


Good Luck.

Dave.

[wyleu]

Are you sure it's the relay?

Can you remove it ( unsolder it)  and do you have a multimeter and a 24 V dc Source of some kind?

[stuartiannaylor]

 Wyleu pointed out a very good observation and that resistor does look very "fired" the big jobber at the top. It looks to heavy duty to just be the coil current limit.

So even though you replace the relay you might still have problems. I lot of relays have similar form factors. But if that worries you just get any relay that is a 24Vdc coil which can match that current or higher. Purchase a relay base for it and instead of soldering direct to the board solder some fly leads instead.

If you decide to do that give us a shout and someone or myself will give you the pin outs.

Personally like Wyleu I have an eye on that resistor and I am wondering, mmmm wonder if it is just the relay.

[wyleu]

You do, of course realise, that a double credit in a post requires at least a smite and the associated three applauds.

this is a time of recession and this sort of stuff counts you know...

[billi]

Dave thanks

I will have a look

wyleu sure not sure   , but on another pump PCB i repaired it was the relay  so hope i have it right again  

But you are right  i  could  take it out (unsolder from the back of the PCB i assume ) and test it somehow ( cant i test when it still in ?)

We manually flush it anyhow (socket switch  on and of ) , so it makes no difference  if the relay is in or out

Perhaps i can attach some sort of a low voltage switch/relay here  , that starts AC circuit of the pump , when someone is flushing   ( cause its only the toilet going in nothing else  

 


  Billi

Ok just read your posts , thanks again  ... can i shorten the resistor just for one time  to see if the relay is ok ?

[Alan]

I would suggest that soap / water residue is the problem.
All the components look OK. But there is plenty of
discolouration on the plastic and aluminium of the capacitors.
Transistor and relay casing.
Lets have a look at the other side of the printed circuit board.
Give it a clean with a minute amount of water on a tooth brush.
Then a dry with a hair dryer, hold it a few inches away.
A good tap with a screw driver handle. ( Not a big Hammer )
on the relay and the pressure sensor. A drip of WD40 down the
pressure sensor pipe, then a few blows down the pipe is worth a go.

Regards

Alan

[wyleu]

Power off the board,

If you stick 24V DC across the coil the correct way you should hear the relay click if it's mechanical

A multimeter will tell you if the contacts on the switched side have operated.

But make sure everything's off before you prod.

As to the resistor It would be a good idea to find out what resistance and wattage it is.

[davebodger]

We manually flush it anyhow (socket switch  on and of ) , so it makes no difference  if the relay is in or out

Billi, that sounds to me like the relay is stuck in the "on" position.
Unless it is a "feature" of the macerator that it runs the pump when the power is first applied.
Did it always work like this?

When you turn it on do you hear the relay click on ?

Dave.