overheat/pressure problem?

[jordy_boy]

Hi guys please help
I have a vokera unica 28 HE which I decided I wanted to add a Honeywell CMT927 wireless thermostat to which I did about a week ago and all worked fine.
However I decided I wanted to move the reciever box which required changing the wire. I dont think this is anything to do with the prob but am telling you just in case.

After doing this I put power back on but when I switched on Hot water tap boiler made strange gurgling noise nd locked out on code 20 (Limit thermostat fault/ fumes thermostat fault).
It wouldnt reset for ages but eventually did. But now when I switch on either hot water or central heating it makes noise again and the pressure gauge goes flying up towards 3bar so I quickly switch off. It then gradually drops down again to 1bar.

Any ideas? Why would the pressure go up so quick? Is it an air lock or something?

Please help thanks guys.

 

[picasso]

I would suspect the pump first, can you hear if the pump is running when you turn on the c/heating.

 

[jordy_boy]

I think it is im having trouble checking to be honest the pressure goes up so fast i cant decide before I have to switch it off. If it was the pump would that also cause the prob on the hot water?

Thanks

 

[picasso]

yes if the pump isint running on central heating or hot water you will have the same thing.

 

[jordy_boy]

Ok I will try and figure out if the pump is running. so if it is could it of been something ive done in installing the thermostat? Could I have knocked off the powr to the pump or blown a fuse to it.
Or is it just coincidence its gone wrong after.
Or could it be air in the pump, cant that sometimes happen? Cos the boiler is only 3 months old surely the pump cant be broken already>

Thanks again for the help.

 

[jordy_boy]

Ok think I might have it. Pretty sure pump wasnt running when I looked closer and when I looked right on outside of pump I noticed it had a switch with 3 positions which i presume are speeds?
Anyway the switch was right in the middle of 2 and 3 so im thinking as I had a right job getting the cover off it must have knocked the switch to neither speed so wasnt working at all.

Seems to work now fine although my next question is what speed should it be on?
Bit of a silly place to have the switch me thinks if you can do that to it.
But anyway thanks for your help my friend for figuring out it was the pump and being spot on.
And as you are obviously a master plumber any ideas on what speed I should go for or can I work it out somehow?

Thanks again

 

[picasso]

as its a combi it should be set on 3.

 

[jordy_boy]

Superb 3 it is then prob 100% sorted.
Thank you again picasso your advice is very much appreciated.