Thanks oilhead.
Replaced the vessel and things did improve, but still seem to have water flow through the heatstore/plate exchanger when CH is in demand. Once again pipes either side of the pump are only warm not hot so diverter valve can be ruled out.
Think I have sussed it though looking at...
I'm back with an update after taking another look today at the boiler.
Decided to drain the system after a flush then to look at the expansion vessel (big red thing on right). Once the system was drained I pressed on the valve on the top of the expansion vessel and rather than 1 bar of...
So when the heating is working and the CH pipe out is hot the return is hot. When the CH is lukewarm the return pipe is only warm and basically the pipe at the back of the boiler marked 'rear of appliance' with an arrow pointing to the back of the boiler gets very hot. I think the heat/water...
If the CH thermostat is set to 1 then the burner is off for a minute or so but we have it at 3 so the burner is normally staying on. When I opened the 3 way it was mucky inside but not sludgy and the ball was intact and still attached. The system is clean but maybe there is something lose in...
We have similar vintage oil burners
Heat store heating lasts about 8 minutes and moving HW stat up and down switches boiler on and off during that time. The startup procedure for the CH from room stat triggering is fan, burner then pump so guess 3 way is triggered same time as fan then micro...
I won't tell you how much googling I've done on this ☺
I've unscrewed the cap and can see the pump spinning, have put a screw driver in to confirm and this morning held a screwdriver on the pump case and other end to my ear to hear rotation.
The water heating is fine, but the random no flow of...
Thanks for the responses John.
I only got air out of the middle right side one so the combustion chamber one. I had the pressure at just above 1 bar and did try it at 2 to see if any air shifted. I've gone round the 9 radiators to check for air and nothing.
Thought i'd connect up my meter to the pump today so these were the voltages and noted behaviour.
Heating luke warm no flow = 240/241v
Hot water only = 243/244v
Heating working fine = 242/243v
Dry pump test went OK and no problems with the running of that. Random behaviour persists though with heating circulation to the radiators. I manually held the 3 way valve so the hot water circuit was closed but still the pipes either side of the pump were cold with the pipe at the back of the...
Thanks for sticking with me on this oilman.
I unscrewed the cap on the heat store so the autovent expelled air and I also undid slightly the silver cap on the pump again to let air out. Couple of things I want to look at today. I was going to get a meter on the pump cable to see voltage...
Not checked the PCB outputs but have an update. Called WB technical and explained the full problem to the guy on the other end and after a confirmation of the boiler he said it's a diverter issue. As I've already changed the head and internal ball valve/spindle I decided to replace the valve...
Its doing it when the hot water isnt in demand and when the heat store isnt being heated. Hopefully i will get something out of the phone call to WB technical line.