Ariston 23 MFFI Intermittent hot water.

[Stevie_diy]

Hi

I have an Ariston 23 MFFI. I'm getting intermittent no hot water although this is becoming increasingly more often. The water is usually tepid, never just cold so there is some heat in it. For a while I have had to top up the pressure every so often but this is becoming almost daily now. Sometimes I come down in the morning and the pressure is right down and the boiler has cut out. A bucket under the heater is collecting some watter most days. I'd like to take out the pump to have a look at it and the DWH diaphram and temp sensor too. However the instructions tell me to empty the boiler first. Could someone advise me how to do this ?

Also, the instructions seem VERY straight forward for removing these parts. Is it really as easy as they seem to indicate ?

I obviously wouldn't touch any gas parts but having been an electronics maintenance type engineer for quite some time I'm reasonably confident removing and replacing parts.

Thanks for any assistance, Stevie.

 

[wossie6]

i have the same problem as you , i think it has something to do with the diverter valve , seems like its a common problem with these boilers , mine is about 6 yr old.my other post..
//www.diynot.com/forums/viewtopic.php?p=764473#764473

I have water tracing down the cable , the leak is in that area.

i have pic to show the area , its not a good pic
http://i2.photobucket.com/albums/y7/wossie/16-12-07_1603.jpg

Seems to be called flow group

http://www.ezypart.co.uk/files/SK005-instructions.pdf

there is a 3 way valve motor that fits into this held on by a. clip , which is where mine is leaking from, if i buy this will it stop the leaks, but most of all is it a easy job to do?

 

[bengasman]

Constant topping up has caused plate heat exchanger to block and probably corrosion in the system.
Clean the system and the h/e, in that order
You may want to repair the leak first though

 

[Agile]

Hi

I obviously wouldn't touch any gas parts but having been an electronics maintenance type engineer for quite some time I'm reasonably confident removing and replacing parts.
Thanks for any assistance, Stevie.

Yes, but electricity does not spurt out of the wires, wet everything and stain the carpet or even bring down ceilings in severe cases!

Tony

 

[Stevie_diy]

I've had a local engineer have a look at this and he's going to replace the pump. I can understand that because there is visible corosion at the rear of the pump. But is the pump involved in the hot water process ? I thought the Hot Water was mains pressure driven. I'm not saying there isn't more than one problem with my boiler but will a replacement pump fix a hot water issue when the central heating seems ok ?

Thanks, Stevie.

 

[Agile]

The pump is required on all boiler operations.

If it works on CH then I dont think the pump is likely to be the cause!

You say its a boiler engineer or is it really a bodger who just changes a few parts ( at your cost ! )

Dont pay for the pump or his time if it does not fix the problem! You are calling him to diagnose the problem not blindly change parts.

Tony

 

[Stevie_diy]

Thanks Tony,

The problem is I have a very intermittent fault. It may very well work when he replaces the pump then stop a day later. I've tried to get it to fail today but every time I run the hot water and the central heating it has been fine.

If it fails how can I tell if the pump is moving ? It is a Wilo Gold and has a big screw looking straight at me when I take the cover off. I thought this was part of the axle and would rotate when operating but I've never seen it move.

There is rust on the back of the pump so it doesn't surprise me if there is a leak in that area.

If the pump is being replaced should the system be drained and refilled ?

Thanks again, Stevie.