Grandee Combi Oil fired boiler

[Belfastcalling]

We have a wall mounted Grandee Combi boiler (oil). Recently is wasnt firing properly and we werent getting HW or CH.

There is oil in the tank OK. I noticed the pressure was below .5 bar and so I removed the cover and found the stop cock. Turning this increased the pressure OK and the heating did come on again .

During the process of trying to find the stop cock i found another valve on the underside. When I turned it water came out (and pressure went down). This wouldnt stop dripping even after tightening so I thought there was a dodgy valve. I left a bucket under it and when I woke up it had stopped dripping. Happy days I though!

During the day, the heating and hot water didnt work so we turned the heating off. Pressure was just under 1 bar. Randomly later on in the day I tried the heating again and both the HW and CH came on and heated up nicely. Again happy days I thought.

This morning I came down and the same thing ... no HW or CH and I cant figure out why its working intermittently now.

Any ideas or troubleshooting tips greatly appreciated.

 

[oilhead]

Do you have to press the reset button on the burner?

 

[holty]

is this a combi or heat only. if i remember grandee did a wall mounted combi. the only valve i can think you turned to release pressure is the drain off on the left hand underside. or the prv. if it is the prv then it doesnt sound attached to an outside termination point. again cant remember a LWP sensor. on these models. are you pressing something to get the thing started. e.g as mentioned reset button on the burner.

 

[Belfastcalling]

Had to press a button on the underside which I think fires the pilot light. This got it going again and the heat is pumping now!!

We tried it this morning too but it didn't work. Strange!

Also the valve that I turned, which released the water is on the underside of the boiler.

 

[Boilerman2]

THe valve you accidently operated was the pressure relief valve (red knob) as it is fitted to the bottom of the boiler (brilliant design-NOT!) it now has carp stuck in it this valve will have to be replaced in order for the system pressure to remain at 1-00 bar.

p.s. the Grandee is without doubt the worst oil fired combi I have ever had the dis-pleasure of working on

 

[Belfastcalling]

What exactly is carp? I thought there may have been some grit stuck in the washer or seal so I turned the presusre up to 2 bar and then used the release vavle on the underside to bring it back down to 1 and flush whatever may have stuck in there.

The dripping has stopped now and the pressure does seem to be sitting steady. It does however move between .7 and 1 when the heatings off and on.

Can anyone explain why the burner isnt firing unless we push the manual fire button on the underside?

Thanks for the response so far, its helping allot.

 

[oilhead]

When was it last serviced? possible oil supply problem, failing oil pump, photocell obscured, combustion head dirty, nozzle faulty etc. etc. etc.