Potterton Promax HE randomly turns off

[remi1990]

Hi all,

I've read quite a few posts on here that have helped me try and diagnose the issue I'm having with our boiler, so thanks for that! But unfortunately we still haven't figured it out.

So far I've spent a fair few hundred on an engineer to come and diagnose the problem, but even he is puzzled what the issue might be.

Some history of events:

• Last Monday our central heating suddenly decided to stop turning on at the usual time scheduled by the programmer. Worth noting that it was very cold that morning.
• I tried resetting the boiler (turn off for 10 seconds then turn on again) and the flame ignites inside, but it cuts out after about 2 seconds. It then tries to ignite again and turns off after 2 seconds. It does this about 5 times before stopping completely.
• We had an engineer come visit, who inspected the boiler and concluded that our condensate had become blocked and worn so they replaced the condensate part (trap I think?) and the boiler was staying ignited. Problem solved!
• Nope. We seemed to have another issue come out of this
• Now when we try turning on the boiler, it appears to work fine and ignites, but after about an hour it suddenly turns off again
• So I called the engineer back and surprise surprise I'm unable to demonstrate the issue because the bloody boiler turned on and stayed on whilst he was there

But the problem is 100% there. I've been trying to see whether there is a pattern to when it decides to turn off, and from what I have gathered so far: when the boiler hasn't been on for a while (i.e. during the evening, so the house is freezing), if I turn on the boiler it ignites and stays on for a good hour sometimes even longer, but then eventually it turns off. If I straight afterwards try to reset the boiler, it turns on fine but then seems to turn off a lot quicker second time round (15 mins). If I try a third time, I'm unable to even get the boiler to ignite...no matter how many times I try to reset it.

So I'm wondering what this means? Is there an issue with my thermostat (which btw seems to click which suggests that the battery is working fine)? What would cause the boiler to randomly turn off? Does that make any sense that it would come on for a shorter period of time the more often I try to turn it back on?

Having already spent quite a bit of cash on trying to diagnose this, I'm hoping to get some second opinions.

Just to give you an idea of our set up, we have a conventional 'heat only' boiler which is connected to a British Gas Dual Channel Programmer. Our thermostat is in the hallway and we have a water tank upstairs where the diverter valve and pressure gauge is located.

Things I've tried/checked:

• Pressure is at about 2.4 (a bit high? could this be the cause)
• Tried bleeding the rads and didn't see the pressure reduce (to be fair, there wasn't much air coming out though)
• When the programmer says the heating is on, if I check the diverter valve I can see that it is open. When the programmer says the heating is off, the valve is closed. So I *think* this rules out the possibility of a fault programmer.
• My thermostat is at 28 degrees
• Instead of relying on the programmer's schedule, I've just set it to always put the heating on, to make sure this isn't an issue with the programmer's clock
• We have an immersion heater upstairs with the water tank so I've set the programmer for the boiler to never turn on the hot water, as I heard sometimes this can take priority over the heat and may result in heating not coming on

Can anyone help? We're quite cold

 

[joni os]

Could be circulation problem. Check temperature of return to boiler.

 

[remi1990]

Could be circulation problem. Check temperature of return to boiler.

sorry but how can I check that? One thing we’ve just noticed as well, is that whilst the boiler was on there seemed to be an awful lot of steam coming out of the extractor outside the house. I’ve never really paid notice to it before but I’m quite sure it’s more than usual. A bit worrying now because I wonder if the boiler is overheating?

 

[remi1990]

I've just checked and here's an image of the pipes going into the boiler. From left to right:

- cool temp
- hot temp
- piping hot

I think the one that is cool is the return to boiler?

 

[joni os]

RH pipe flow, middle pipe return. Difference in temp indicates circulation. However, with room stat. at 28 degrees TRVs will be closing down before call for heat is satisfied Remove head of TRV from large radiator and see if issue goes away.

 

[remi1990]

Tried the above this morning with no luck. Worth noting that the first time I turn on the boiler in the morning (after it's been off all night), it ignites fine and I see a blue flame.

Then after it turned off again, I left it for about 20 mins and then tried to reset the boiler again. This time around, it ignites but the noise is much loader, feels like a big ignite and the flame is more orange.

It just can't seem to stay on longer than about 45 mins/1 hour

 

[jtsplumbing]

What are the lights on control box doing ? number of reasons it could be overheating ! Edit open forum.

 

[king of pipes]

Edit too much information on open forum.

 

[Riley]

Guys. Open forum

 

[joni os]

The orange flame is significant and that alone indicates you need to a Gas Safe engineer.
You have eliminated circulation as the problem, external controls seem in order.Someone familiar with Potterton boilers should be your next call.

 

[joni os]

The orange flame is significant and that alone indicates you need to a Gas Safe engineer.
You have eliminated circulation as the problem, external controls seem in order.Someone familiar with Potterton boilers should be your next call.

 

[remi1990]

Right, thanks very much guys - you've been a big help. Very concerned about this now...I've contacted the engineers to see if they can sent a different engineer to get a second set of eyes. For the time being I'll keep the boiler off. I'll also get some carbon monoxide alarms (I know I should already have these).

Is too much air to the boiler something that can actually be fixed?

 

[remi1990]

Right, thanks very much guys - you've been a big help. Very concerned about this now...I've contacted the engineers to see if they can sent a different engineer to get a second set of eyes. For the time being I'll keep the boiler off. I'll also get some carbon monoxide alarms (I know I should already have these).

Is too much air to the boiler something that can actually be fixed?

 

[newcastle phill]

You need a new engineer.

 

[Rickster123]

Good advice given.