RDB cycling

[Bunker]

Had an interesting one:

Last week I went to a boiler that was 'running' but the rads hadn't been getting hot. The neighbours' plumber had been round and fitted a new circulating pump in the airing cupboard - £200.
Next day, rads still not getting hot, call the boiler engineer, me.

Camray5, RDB cycling (burner running but not firing or locking out). So plumber thought the boiler was going but didnt notice there wasnt any heat anywhere (rolling eyes).

Photocell? Of course its the photocell - new one fitted and all sorted.

Called back today, same again. Mmmmm. Photocell all ok (double checked old one [left in boiler cab] and yes, faulty), new one is fine. Must be the control box, unusual, but what else? New control box on and .... same.

50v to white wire ok.

I rang WB who straight away said 'coil'...and it was. I hadnt had that before, you very rarely get a faulty RDB coil but worth remembering the above as a symptom.

I also decided to leave the new control box on, I felt is was a bit weird that within 7 days, a photocell and coil had gone on an RDB and wondered if the 535 had a gremlin within.

Anyone else had this?

 

[SimonG]

I would have gone photocell then control box as well.

 

[jensda]

a lot of people wont be aware that the constant running on an rdb can also be caused by a faulty coil as it is so rare to see a faulty rdb coil maybe changed 2 in 6 years

I had 1 like this about 3 years ago and spoke to graham in riello who advised to check in this order
photo cell coil control box 50v to white wire

 

[Bunker]

a lot of people wont be aware that the constant running on an rdb can also be caused by a faulty coil as it is so rare to see a faulty rdb coil maybe changed 2 in 6 years

I had 1 like this about 3 years ago and spoke to graham in riello who advised to check in this order
photo cell coil control box 50v to white wire

Thats pretty much word for word what I wrote

 

[jensda]

Thats pretty much word for word what I wrote

was agreeing 100% with you bunker and your problem solving route was exactly as
riello would have advised in case you thought otherwise

my post was a comment not advice

 

[bennythedip]

Great tip Bunker, came across this exact problem today and had it sorted within minutes as I read it last week. Just wondering does the same apply for the riello G3 or is it just the RDB?
Thanks again, every day's a learning day!