Ariston Euro Combi

[glaston]

I hope someone can help.
I have a problem with the hot water only working when the heating is on.
I think I know what the problem is.
On the left hand side of the boiler is a pin that comes up when the water is turned on and contacts a small micro switch. The pin is not coming up enough to make contact. Could someone please tell me what this unit is called so i can buy spares or a new unit. I have previously replaced the diaphragm in the diverter valve on the right hand side.

Thanks

Garry

 

[frankthegasman]

this is probably the diverter valve right hand side at the rear, base, big brass valve, get a rgi to ex it as it can be tricky good luck.

 

[glaston]

I have already replaced the diaphragm in the diverter valve on the right hand side and it was tricky but not too bad. The problem I have is on the left hand side and a much smaller unit

 

[Agile]

That is the system flow switch. There are about 11 different models called Eurocombi !!!

If its not operating the cause is usually a dirty or slow running pump or if on DHW only a blocked secondary heat exchanger.

It could be the flow switch but most unlikely.

Its probably the pump but its most likely to be the long shaft type which is not available any more.

Do a finger torque test on the pump if the impeller is clear. If its weak then email me and I will tell you a trick to fix it.

Tony

 

[frankthegasman]

it could be that the tube off of the diverter is partially blocked the small tube on the left that goes to the little valve under the microswith or the diapragm in the small valve may be faulty, good luck.

 

[glaston]

Thanks for your replies.
The model of the boiler is Ariston Euro Combi Boiler SX20.

I will look at the pump.
Thanks Tony.


Thanks frankthegasman.
If it was the diapragm in the small valve would the pin still make contact for the heating because this works fine. Can a new diapragm be bought.

Garry

 

[ChrisR]

Everything can be bought, but don't , yet.

90% chance, pump

 

[Agile]

I would have said 90% pump but he has now said it works fine on CH.

In that case there is still a chance the DHW heat exchanger circuit is rather blocked.

I would reduce the pump odds to 75%.

Tony

 

[DP]

I say replace the pump

 

[Gasguru]

When I've seen this problem before (HTG ok, DHW not ok) it's been due to a partial blockage on the right hand connection to the main heat exchanger. It has a very thick washer and crud builds up on the inner edge. You need plenty of room on the right for the adjustable.