Potterton Statesman - new controller

[TooLazy]

Firstly, sorry if the terminology is wrong I'm a PC engineer not heating engineer.

Just had a new Honeywell ST9400Ccontroller fitted to my Potterton Statesman (not Flowsure) based CH / HW system to replace an old clockwork one. As it was an insurance job it wasn't my usual service engineer. This guy said he'd never seen a system like mine before (separate pumps for CH and HW each with stats in the circuit). I now find that both the pumps come on whenever either HW stat or CH room stat comes on, so heating pump runs when the boiler comes on for HW and vice versa. I should say with old clockwork timer each pump switched on as required with boiler starting and stopping when needed. Only found out yesterday evening so can't contact them till Monday and want to understand the issues, so just some questions.

1. I am pretty sure the boiler mains light was on full time previously and now just comes on when the stats are on. Should the boiler be connected to the mains full-time as the manual suggests? Would this explain why the boiler seemed to start up in the middle of the night for a short while then shut down.

2. Should each circuit just include the timer channel, stat and pump to complete and start each pump when needed or should it have a mains control to the boiler as it is now set up?

Appreciate any help from the knowledgeable people on this site.

 

[Agile]

Of course it was correct as originally wired up.

Unfortunately you have had someone who is not competent to do the job properly!

When its done under an insurance claim you may have quite a job getting it done properly.

Please make a fuss to the insurance company as they need to be made aware that their cheapo contractors are not doing an acceptable job.

Tony

 

[TooLazy]

Thanks Tony,

If I connect the boiler directly to the mains it comes on straight away. I am guessing once the boiler thermostat kicks in it will switch off until one of the pumps starts. Does this sound right?

 

[Agile]

No !

The boiler would normally not be allowed to fire up unless a pump was running. I also expect that it has a pump over run.

There would usually be a permanent live to the boiler and a call for heat connection.

There are many possibilities about how to connect the system so I do not know how yours has been connected. However the original operation was correct.

Tony

 

[ChrisR]

Would this explain why the boiler seemed to start up in the middle of the night for a short while then shut down.

Was that with the old or the new connections?

Are there ANY relays or motorised valves? If not, off the top of my head I don't think it could ever have been optimal - the boiler would have been sitting there cycling all the time waiting for a pump to come on.

Google Pump Plan...

 

[TooLazy]

Yes this was with the old setup. The boiler itself has a thermostat on it too which is why I think it was switching on and off without the pumps being on.