New diverter valve, now boiler won't fully fire up!

[DarkPedals]

Hi,

My boiler is a Sime Super 90 Plus combi. The diverter valve needed replacing, so I bought a new one and did this. The new valve (seems to) work a treat. BUT, in changing it I think I've inadvertantly done something bad....

When I try to run hot water, or use the central heating, the boiler fires up, but only at a very low level - the flame never hits anything like full and as a result no water is ever heated (either for DHW or CH).

Here is one strange thing though, and I don't know whether it's important - you can rotate the pump round - it isn't easy to do but it isn't secure by any stretch of the imagination - could this have become looser and caused the problem?

Also, when changing the valve over, there was quite a bit of excess water all over the place - I don't THINK this went on any of the electronics but maybe I'm wrong?

Any guesses?

Thanks,

Bob

 

[ChrisR]

SOUnds like you knocked a wire to the gas valve. Or got one wet, in which case a good night's sleep may make it better.

 

[DarkPedals]

Thanks Chris,

OK - I've had a good night's sleep now (well, 5 hours anyway) and it's still not working....

SO, I've taken off the cover to the electronics....

When the CH or DHW is 'on', there is a small device on Power PCB which flashes every 1 second or so - this looks like a Piezo lighter / ignition?

If I'm looking for a loose wire on the gas valve, forgive my naivety, but which one is the gas valve? I presume it's the device which the gas goes into and out of (dur!)?

I've had a look and can't see anything loose - I'm sceptical about doing much with this though owing to the fact I'm now dealing with gas rather than water....

It is time to get the pros in?

 

[DarkPedals]

One more thing....

What is the device, on the gas valve which looks a little like a solenoid but is labelled 'proportioning unit (24)'?

This is loose as well?

Bob

 

[DarkPedals]

OK, I'm getting there now....

The ignition is firing constantly - every second or so. The pilot gas solenoid is working fine - when it isn't plugged in, you don't get any flame - when it is, you hear it click once and the pilot ignites.

The main gas solenoid doesn't appear to be doing anything - when you plug it in (with DCH switched on!), it doesn't click, it doesn't do anything. I'd guess that this means it isn't telling the gas valve to open up the main gas, hence the boiler isn't fully firing up. Should I hear this solenoid click?

So, I think I've got it down to one of three things....

1. The 'proportioning unit' - whatever this is!
2. the ignition PCB
3. the main gas solenoid.

Do people agree? Is there anything else I should look at? Is it more likely to be a particular one of the above?

Thanks!

Bob

 

[Agile]

What we might all agree on is that you probably need a CORGI boiler engineer.

Sounds as if the pilot flame is not being detected.

Tony

 

[DarkPedals]

Thanks Tony,

However, I think a bit of a rest did the boiler good. I presume I'd got some water in the 'main gas' solenoid when changing the diverter valve. After a few more hours it started firing up properly and it's now working as new again.

By the way, I think my diverter valve for £25 was a bargain when I was expecting to have to pay £150 plus (possibly) and engineer!

Bob