Oil fired boiler refusing to start after changing a radiator

Hi.

I've spen the last 5 hours trying to fix this issue, but changed get it to go!
I've trawled through this website, but to no vail, so here goes.

It's an external Camray 15 oil fired boiler.
I've got a Santon unvented sealed water tank.
I stay in a 2 storey house, with 6 radiators downstairs (+ boiler and hot water tank) and 2 radiators upstairs.

I changed a downstairs radiator (made it larger), which ment I had to cut into the feed pipe and T in a new 15mm to the new radiator.
I drained a lot of water out till it run nearly dry (say 20 litres).

I re-filled the system as normal, bleeding all radiators starting from the nearest rads to the furthest away rads, then upstairs.

The 2 port switches for the heating and water is going fine, as is the pump.

The trouble is the that boiler doesn't want to kick in.

The 'LIMIT' switch is on all of the time. When I hit the reset button, the 'LIMIT' light dims, but does not extingwish.

I've drained the system 4 or 5 times now and even opened the drain below the boiler (which water did run).

What else can I do? Thank god we have a wood burning stove for tonight!!!!!

The "LIMIT" is the overheat trip. You have run boiler with air in it, and it has overheated. There is an overheat stat which you have to reset. It is either a visible button, or it will be under a cap like a round fuseholder. You need to make sure the boiler has no air in it.

I just ran outside right now (yes that is snow!) of the boiler in question.

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In the 2nd last pic, the fitting on the RHS is a pressure type (with an internal spring). I heard it hissing after refilling the system, but then stopped. The 'LIMIT' light still said alight.
I flicked the 'TEST' switch and you heard the pump running (inside the house), but the LIMIT light stays on and the motos doesn't even turn.

There is he reset button on the burner which might need pressing (but probably doesn"t) to get it started, but there is a button somewhere on the black box that needs pressing to extinguish the light. It might be near the control thermostat.

There is a metal part that sticks out, just above the thermostat.

I'll go give it a go and be back in 5.

Oilman...............................YOU ARE A STAR!!!!

I never knew that was a button! It was a star shaped button that only moved in flush with it's outer casing. I hit the TEST switch and it kicked into life!

Well, this issue has wasted my pre-planned Sat night, but at least I've learned something new, which is nice.

rocky_robin said:

Well, this issue has wasted my pre-planned Sat night, but at least I've learned something new, which is nice.

Click to expand...

You certainly have, and that is, central heating is krappe, a wood burner is 100% reliable.

lol
I knew that a lllooonnngggg time ago! Just a pity the hot water isn't plumbed into it too, or else I'd be more happier!

Can't beat a fire during a cold winter's day, such as today.

Thanks once again.