no heating after changing radiator valves

[eddiemacthedog]

Hi all, changed radiator valves today for a towel rail in the en-suite, now its a combi system bosch highflow 400 with 8mm microbore :evil

not to familiar with combis, so cannot find a drain cock at all, so i flattened system through the blow off valve to get the job done.

I changed the valves topped up the system again, bled all the system radiators etc again, put some life back in the boiler and pump isnt starting and hot waters goosed as well i reckon.

im guessing an airlock but where to start?

please please help as i have young kids in the house and it looks like we will have no CH or HW until this is sussed out.

thanks in advance.

if you need more info ask as i will be glued to this thread.

 

[eddiemacthedog]

forgot to say, boiler powers up etc but pump wont start.

 

[keego]

If it was an airlock then the boiler would fire up & get to temp very quickly then shut down, as yours is a storage combi it should fire up & heat the store up first before you would get any CH.
Draining via the blow off is not a very good idea as it could start weeping & losing pressure through that, have you still got pressure on the guage?

 

[keego]

If i remember right the pump wont run until the heat store is up to temp, does the boiler fire up at all?

 

[keego]

Try the overheat stat it might have popped if you turned off the power while it was running, I think there's 2 of them under the lip of the grey control panel at each end, it's a little red button which will click if it had tripped.

 

[eddiemacthedog]

will try those trip switches and report back. drained to zero pressure, changed valves, repressured with filling loop to 1 bar, pressures holding but no go.

 

[eddiemacthedog]

trid the switches not sure if they had tripped or not, booted her up, boilers doing something, cant hear pump though, i feel the radiators warming up slightly.

seem to be warmer at the top of the radiators than the bottom, any significance?

 

[keego]

Boiler runs without pump until heat store is up to temp, from cold this could take up to 20 min, after that you will get pump & CH running.

 

[eddiemacthedog]

rads all toasty now seems to be back to normal. So if i have to drain things down again, should i use the drain of the bottom of the boiler termed primary water? as there is no drain cock that i can see.

cheers

 

[keego]

NEVER EVER! use that drain off as every time I've used it the washer falls apart.
If you need to drain off again & you have no drain off, take a rad off & drain off from the rad valve, also turn the boiler off at the programmer & let it cool for a bit or the overheat stat will pop again.

 

[eddiemacthedog]

thanks for that, was always going to drain down and put in some cleaner as dont know when it was last done, have a rad close to the back door, ill use that.

Thanks for all your help by the way, really appreciate it.

 

[Dan Robinson]

Boiler runs without pump until heat store is up to temp

That's jolly clever of it .

 

[keego]

That's jolly clever of it .

And by that you mean what?

 

[Dan Robinson]

Of course the pump is running.

 

[leakydave]

When you drain down next time, fit a lock shield with built in drain off on it... preferably downstairs and near front or back door.