Ariston Eurocombi - faulty divertor valve..???

[phoenix]

Ariston Eurocombi SX20 MFFICE (6 yrs old)

Problem: DHW is not running very warm (been like this for a week)

However, the C/H (although no demand) is ON.

Possible cause: faulty divertor valve - sticking open on both DHW & C/H

Would appreciate someone with greater experience adding their view

Thanks in anticipation

Mike

 

[weargas]

However, the C/H (although no demand) is ON.

All of the time or only when you're running hot water?

 

[ChrisR]

Can you find the dv and see if its pin is llifting smartly (rhs of boiler) on HW drawoff?

 

[phoenix]

1. Weargas - C/H comes on when ever the DHW is run, hence explaining the lack of heat in the DHW.

2. ChrisR - Appreciate the point about the DV pin - I will look and check.

3. Could another possibility be that the heat exchanger is full of debris..?? could this have this effect..?

 

[ChrisR]

In answer to
1: yes we realise that; what Weargas means is does the ch come on by itself when it isn't switched on and the hw isn't being drawn?

2. There are loads of diffrent Eurocombis but most have the dv on the right, with a wide bit at the top about4 inches across, with microswitches in a plastic box , on top. The box swivels round so you should be able to see the pin - a T shaped top end , which operates the switches.

3. No. But the diverter body being full of debris can be one reason why it doesn't divert. Why do you ask?

 

[phoenix]

1. C/H only comes on when DHW is drawn

3. a comment from another colleague

Hoping to get in and have a look in next day or so - will update you on result.

Thanks.

 

[phoenix]

Fault fixed.

DV valve was heavily limescaled up and very sluggish in movement.

Also, when I stripped down the DV I found 4-5 smallish pebbles in the valve.

Gave a good cleaning out.

All now works well.

Client said that the DHW had never been so good.

Thanks to ChrisR & Weargas for suggestions.

Mike

 

[phoenix]

Same old Ariston Eurocombi 24SX i'm afraid.

DV getting stuck again with DHW getting cooler. Will clean out and recommend replacement.

However, strange prob with air pressure switch. Boiler currently NOT firing up until I short out the Common and NC (or C + NO) on pressure switch. Then appears to work okay.

Tried connecting C + NC + NO together but no firing up.

Any ideas/solutions? I've tested the switch with ohmeter and all seems ok.

 

[ChrisR]

Sounds like a dirty system causing the dv to clag up. A filter on the return would protect the dv but need cleaning itself!

If you're simulating the aps and it works but the aps itself doesn't make it work, your simulation isn't very good!

Check that mains is going from the pcb to the aps AND BACK before the fan starts, and that its still coming from the pcb when the fan starts and runs and the aps should switch over. If the PCB finds something wrong (like say a shorted electrode lead) then it'll remove the signal OUT from the pcb to the aps.

 

[phoenix]

Thanks ChrisR.

Chkd today and discovered small hole in tube from aps to flue. Ariston said that it should have a small brass fitting to let out any condensation! Removed piece of tube with hole - all now fires up okay. Comments!!

Took DV to pieces and discover badly damaged diaphragm with hole in it. Now ordering new one via Ezypart.

 

[ChrisR]

should have a small brass fitting to let out any condensation

The last one I worked on had aps problems, but no little brass fitting!

I wouldn't dream of buying from ezypart - far too dear![/quote]

 

[phoenix]

All fixed. Replcd diaphragm. Also had to service lower valve as this had deposits on the valve seats.

Thanks

PS complete service kit cost £21 from R F Symons at Ruislip

 

[Rchard]

Hi phoenix!

Longshot but are you still around - and near Eastcote? Have a prob with the boiler - wondering if you can take a look at.

Cheers!

Richard
07855 762 055

All fixed. Replcd diaphragm. Also had to service lower valve as this had deposits on the valve seats.

Thanks

PS complete service kit cost £21 from R F Symons at Ruislip

 

[Agile]

When a client telephones us and says he has a "small problem" it usually turns out that he has a big problem but only wants to pay a small price !!!

It actually makes little difference because we charge the same fixed price to diagnose all faults!

Tony

 

[Paul Barker]

While you're here would you just put me these new bath taps on? Just a little job. Yes my wc is right beside the tap end of the bath, does it really smell of p11ss down there? I'm sure it doesn't. Don't break my pedestal banging your head on it trying to get your other arm in under the bath.