Ideal classic RS40 not staying on burn.

[fixitflav]

If you have voltage at the MFV the stat is not the problem.

I doubt it's a control-stat problem. As it's not used for HW, with an output of only about 12kW, if there's plenty of rad area it won't reach control-stat setting, just fire until it goes off on the room-stat. That's what my system does, it only stops on control-stat on HW (it's W-plan) when it cycles 3-4 times before the cylinder stat is satisfied. Previous house was the same.

 

[fixitflav]

fixitflav. Trouble is, I'm not even sure the problem is the control stat. Could be the gas valve or anything really, but definitely in the boiler. I could end up changing everything, including the drop down front panel which dropped off years ago! The burner is also showing its age with lots of rust, as it is mounted on a single skin outside wall in the garage, so moisture gets in all the time. Bottom of the boilercase looks like it's covered in gravy granules.
As I said to ianmcd, I am happy with my decision to change it after 29 years, but I wouldn't mind placing a bet that the new one will fail well before that!

Posted my last one before seeing this! Interested in the problem, but you're right, it doesn't seem a bad idea to upgrade the boiler

 

[fixitflav]

Bottom of the boilercase looks like it's covered in gravy granules.

Could be mouse poo!

 

[foxinthehouse]

Could be mouse poo!

No, definitely rust. (Unless the mice have been eating the boiler!)

 

[Terrywookfit]

Check the solenoid coil resistance when it refuses to fire.

 

[ianmcd]

and neither are you fookwit, he asked for advice and he got it no thanks to you Fookwit

My sincere apologies, I thought I had deleted that, I realised after typing it that I had read your response wrong

 

[kidgreen61]

The Classic is a bomb proof boiler, as said by others, parts are easily obtainable.
I would take 3+ hrs to change a mid pos valve if I had to do it blindfolded, with one hand.

 

[foxinthehouse]

I would take 3+ hrs to change a mid pos valve if I had to do it blindfolded, with one hand.

Just to give the guy his due, it only took a few minutes to change the 3 port valve, which he first diagnosed as the problem. It wasn't, which I knew anyway. The rest of the time was spent looking for a fault in the circulation, even though the pump was brand new (fitted by yours truly) and showed a circulation of 1.1 cubic mtrs. Oh, and head scratching of course. Real problem was that even after all that time, the fault was not diagnosed. I was a bit peeved because, as already mentioned, I don't use the gas for hot water and, if I needed it, I could have replaced the valve myself for a fraction of the cost.

 

[gas112]

Just to give the guy his due, it only took a few minutes to change the 3 port valve, which he first diagnosed as the problem. It wasn't, which I knew anyway. The rest of the time was spent looking for a fault in the circulation, even though the pump was brand new (fitted by yours truly) and showed a circulation of 1.1 cubic mtrs. Oh, and head scratching of course. Real problem was that even after all that time, the fault was not diagnosed. I was a bit peeved because, as already mentioned, I don't use the gas for hot water and, if I needed it, I could have replaced the valve myself for a fraction of the cost.

you fitted pump , you did fit it pumping correct way .
so do you use solar for hot water ?

 

[foxinthehouse]

you fitted pump , you did fit it pumping correct way .
so do you use solar for hot water ?

Flow on pump is correct. No solar, With just two of us in the house all the time I find the very well insulated immersion heater on 24hrs is by far the cheapest way to have hot water whenever we need it. We shower, so have never run out of hot water, even though the immersion only heats the top third of the tank. Watching the smart meter monitor device, the immersion is only on a few minutes at a time after drawing hot water.

 

[fixitflav]

immersion heater on 24hrs is by far the cheapest way to have hot water whenever we need it.

I'll second that. Several discussions on here about timer control of HW, whether by gas or immersion. Usually more trouble than it's worth.

Check the solenoid coil resistance when it refuses to fire.

My guess is that's the most likely explanation. Some years ago my boiler failed to fire. The gas valve has 2 solenoids and one had failed, open-circuit. Replacement fixed it.

 

[foxinthehouse]

I'll second that. Several discussions on here about timer control of HW, whether by gas or immersion. Usually more trouble than it's worth.

There is another good reason. The Ideal Classic has a pilot light. At current gas prices it has been costing me 80p a day according to the IHD. (The boiler has been off since 1st April, but I left the pilot light on just to see).
On average, I have been turning the boiler off from May to October. 180 days at 80p. That is a saving of £144. I don't think the immersion costs that over the summer months, so you could say I get free free hot water in the summer.

 

[gas112]

There is another good reason. The Ideal Classic has a pilot light. At current gas prices it has been costing me 80p a day according to the IHD. (The boiler has been off since 1st April, but I left the pilot light on just to see).
On average, I have been turning the boiler off from May to October. 180 days at 80p. That is a saving of £144. I don't think the immersion costs that over the summer months, so you could say I get free free hot water in the summer.

you sure your not including your standing charge in that 80p a day.
So you think heating your water with electricity 3 times the price of gas is cheaper ?

 

[fixitflav]

There is another good reason. The Ideal Classic has a pilot light. At current gas prices it has been costing me 80p a day according to the IHD. (The boiler has been off since 1st April, but I left the pilot light on just to see).
On average, I have been turning the boiler off from May to October. 180 days at 80p. That is a saving of £144. I don't think the immersion costs that over the summer months, so you could say I get free free hot water in the summer.

Yes, I had a boiler with pilot light years ago, and it did use a fair bit of gas. In the manual for the RS40 it says the pliot flame should be 1 inch long!! No wonder it gets through some gas.

 

[foxinthehouse]

you sure your not including your standing charge in that 80p a day.
So you think heating your water with electricity 3 times the price of gas is cheaper ?

The IHD is reading zero for today, so I don't think standing charge is included. Even if it is, it would be 53p a day and a saving of £95 over six months. My argument stands.

Yes, heating MY water is significantly cheaper on electricity than gas. My bills prove it. Using gas takes far far longer and the heat exchange system is inefficient compared to direct heat, so the comparison of unit prices is irrelevant. It is the cost of a tank of hot water that is important.