Ideal Icos HE15 heat only boiler and central heating problem

[steveuk1971]

I have an Ideal Icos HE15 heat only boiler. A hot water cylinder in the airing cupboard and this has 2 x 2 port valves (one for water and one for heating circuits) and a small tank in the loft. As it got colder today, I put the central heating on for the first time since April 2023. The room thermostat called for heat, the motorised heating 2 port valve whirred away and the boiler fired up but only for about 30 seconds then the boiler LED just flashes constantly and the letter c shows. The boiler remains in this state and does not fire up again. There were a few glugging noises prior to the constant flashing LED.

If I turn the hot water to the on position all works normally, (boiler fires normally, constant white LED light and letter c on the boiler display) so it is just a problem with the heating circuit only.

Video of the problem here...

Any ideas, people? Much appreciated.

Steve

 

[terryplumb]

Run boiler for hot water ,and manually latch open the zone valve for central heating. radiators should heat up .
Let us know the result.

 

[steveuk1971]

Run boiler for hot water ,and manually latch open the zone valve for central heating. radiators should heat up .
Let us know the result.

Hi. Thanks for your reply. Tried that now. Turned on hot water programmer. Boiler stayed on. Radiators remained cold with the 2 port valve head on the heating pipework was held and latched open manually. The pipe above the heating valve was hot. But cold under the valve. Does it sound like the heating valve itself is stuck closed ( despite valve actuator forced to on position) and no flow of water despite pump on? Would that cause the boiler to not work and flash constantly if only heating on?

 

[CBW]

Aye, could be. Is the actuator detachable? If unsure post photo of valve

 

[terryplumb]

Certainly sounds like there is no water flowing through the valve and the gate is stuck closed.
Was programmer calling for heating as well as hot water when you did trial ?
When latching valve manually,sliding lever, did you meet resistance from spring pressure ?

 

[steveuk1971]

Aye, could be. Is the actuator detachable? If unsure post photo of valve

It's a Danfoss HPA2 like this.

 

[steveuk1971]

Certainly sounds like there is no water flowing through the valve and the gate is stuck closed.
Was programmer calling for heating as well as hot water when you did trial ?
When latching valve manually,sliding lever, did you meet resistance from spring pressure ?

Hi
Yes there is resistance on the manual lever. Programmer was calling for both water and heat. Copper pipe above 2 port heating circuit valve hot and below valve cold. So does seem no hot water in the copper pipe is passing through the valve despite the actuator turning. The boiler turns on as the microswitch activated when the valve lever opened. And then 30 seconds later the boiler turns off the burner and just flashes constantly the LED burner light. Does the boiler have a safety thing in it to stop heating if there is no flow of water through the pipe (presumably as the port valve is stuck?)

 

[steveuk1971]

Thanks

 

[CBW]

It's a Danfoss HPA2 like this.

Looks detachable - via the 2 screws, remove the head and see if the spindle is easily moveable by finger and thumb, or if stiff with pliers.

 

[kidgreen61]

Header tank empty?

 

[steveuk1971]

Update... heating called out. Took the heating 2 port valve off (The whole valve, not just the actuator) and replaced it. The valve ball bit inside was broken and stopping the flow of water and the boiler overheat had kicked in, hence the constant flashing burner light on the boiler. All works now.