New diverter valve. Boiler over heating

[trevorbayliss]

Can anyone say if the Descalers are ok to use or do I need a specific acid? Spirit of salts is online but I can get the descaler today

 

[kidgreen61]

We use brick acid, easilly available & does the job.
It's normally the primary side of the plate that blocks from the muck in the system.

 

[fixitflav]

I treated it before the diverter was changed on the day with spirit of salts. I guess I didn’t allow enough time to dissolve the line scale.

That's dropped in a bit late in the thread!
Is that what most people nowadays call hydrochloric acid? Are you putting it in the whole system, or somehow treating the plate heat exchanger alone? I'd be nervous about putting HCl into carbon steel rads. More common to use a proprietary descaler.

 

[DP]

Ok. Can you tell me what needs to be done on a service. I have it done every few years. Last done in jan this year. All engineers do is clean out the main burner. I’ve watched before and my burner is quite clean inside. Then it’s a new seal and that seems all they do.

I have a mag pro 2 filter as well so my system is pretty clean.

Pressurise expansion vessel, clear out condensate syphon, flue gas analysis. Tad surprise the burner is removed every year during service

 

[trevorbayliss]

Update: I have got it working. I took out the water HE and used the brick acid to clean it out. Did 2 x 20mins standing then a flush out.

When I started it up again the boiler came on, but only for a minute (heating only). There were a few loud noises, groaning as if something was blocked. Then it fired off and stopped for a minute. It then started again and repeated. I think on the 3rd fire up it stayed on fine and was just working, so I left it for 10 mins.

I then tested the water and it was ok.

The heating has been running for 1 1/2h now. Ive just had a shower and all ok.

So I think it has been fixed, but I am still a little nervous.

Boiler will be 17yo in April. I may get a new boiler next summer. Will see how it gets on.

 

[trevorbayliss]

Pressurise expansion vessel, clear out condensate syphon, flue gas analysis. Tad surprise the burner is removed every year during service

I see, yes all these things get done on the service. But the burner doesn't come off every year as I don't have it done every year. I think its been off 4 times in the 16 years and it is always pretty clean inside.

 

[Johntheo5]

Strange though why a blocked PHEX should have affected CH operation.

 

[trevorbayliss]

This all happened on Friday night after DV replaced. Heating was working but when I went to bed the boiler was off showing an F20 code I think (over heating). Wife had run the bath and it was Luke warm. So looks like end of evening the HW caused the boiler to stop.

Then it gave out F75 code. Sat morning it wouldn't come on in any way.