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I replaced a couple of TRVs earlier, and prior to starting I powered off the boiler (a Main Heat 15). Boiler is 7 months old, and never been isolated from the mains before today.

Once all the rads were bled, went to power on the boiler and now the pilot won't ignite. And the reset button doesn't do anything.

As a total novice I'm not intending messing with anything, but does anyone have any suggestions?

Thanks
 
Do you have the same issue for Hot Water and Central Heating? Or is Hot Water only ok? If it is both not functioning:

Is this operating on a sealed system?

If so:

Check that you have properly repressurised the system - it needs to at least 0.5bar

Check that you have power to the boiler.

Follow the reset procedure ( it is very simple) set out in the users manual - but you need to follow the precise process to ensure that the boiler has reset.

If it is only not operating on heating:

The motorised valve (s) would be my first point if call to find the fault.


Thereafter, if no success you need a Gas Safe Engineer to look at it
 
Hot water seems OK, that seems to be the only the pipe that gets hot. Though I can't see the pilot light, so that's confused me..!

Yeah, it's pressurised OK, I took it up to 1bar.
 
Hot water seems OK, that seems to be the only the pipe that gets hot. Though I can't see the pilot light, so that's confused me..!

Yeah, it's pressurised OK, I took it up to 1bar.
It doesn't have a pilot light.
 
Think maybe I surpassed myself managing to replace the TRVs without flooding the house! Need to call in the experts to get it up and running in that case..
 
The heating wont come on if the thermostat isn't set high enough.

Set it on 25C and see if it fires up.
 
Is the pump running / can you hear it running
 
The pumps actually a lot noisier than before, and it's getting hot (the pump) after 5 or so minutes.. But the rads aren't..
 
Sounds like an airlock. Have you bled the pump or any airvents on the system? Have you bled the rads?
 
I bled all the rads. Didn't know I could bleed the pump tbh..? Or anything else.

Now's when I wish I'd left it alone.. Obviously don't know enough about the system, and thought I'd be clever and replace the rad valves. :(

So.. I just bled the pump. No air in that.
 
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What motorised valve(s) do you have? You have opened the trv’s? Have you missed anything simple like the programmer? Also as per Craig, a photo at this point maybe good.
 
I've opened the TRVs, programmer is all ok, think I did all the obvious checks.

As for the motorised valve, I think it's a 3 port, but will add a pic of that too. I think that was playing up before today, as when I had hot water only on, the upstairs rads were heating up.

Hope the pics help..

IMG_20190608_220224.jpg


IMG_20190608_220235.jpg


IMG_20190608_220250.jpg
 
Always baffles me why installers are happy to replace the boiler and use the existing pump.
You could try turning your heating on, then using the speed selector on the side of the pump. By slightly turing it towards setting 2 but not actually going all the way, you'll hear the pump power off, do this for 10 seconds, then switch it back to 3 for 10 seconds, then off again and repeat for a fee minutes. If there is any air this could help dislodge it.
 
Yes you have a 3 port valve. Select heating and feel the pipe off the port labelled a, see if it gets hot. If not try heating and hot water together and see if it gets hot.
 
OK, so I've tried both suggestions, thanks Craig and cbw.

Pipe A doesn't get hot in either scenario. Also, I'm not sure of the relevance, but there's no resistance on the lever on bottom of the 3 port valve, whether the heating is on or off..
 
Is the pipe for B getting hot? If so note what cylinder stat is on then turn down to say 20 so it isolates that.

Have you adjusted the pump speed?

You have a bypass valve is that getting hot? Turn that off.
 
Is the pipe for B getting hot? If so note what cylinder stat is on then turn down to say 20 so it isolates that.

Have you adjusted the pump speed?

You have a bypass valve is that getting hot? Turn that off.

Pipe B. Nope.

I did try the pump at 2 setting for a while. No difference.

What's the bypass valve?
 
Might be worth mentioning, when I said

"As for the motorised valve, I think it's a 3 port, but will add a pic of that too. I think that was playing up before today, as when I had hot water on, the upstairs rads were heating up."

That's no longer happening. The rads don't heat up at all now..
 
It would suggest to me that there’s an issue with your 3 port valve then. If it’s not something you can do yourself safely, then you may need to call an engineer in.
 
Back again, something's bugging me..

So my replacement 3 port valve is on its way. Had a look at the steps involved and I was happy to take it on.

Howewer, I still have the initial issue.. The boiler wont ignite. I whack the room stat up to 25+, make sure there's 1bar pressure, and switch heating to on. The pump kicks in, makes a bit more noise than usual, but there's no burner light on the boiler when I look in the peep hole.

And none of the pipes off the boiler get hot.

So I'm assuming I have more issues than the 3 port valve..?

Maybe just easier to get the engineer round I guess.
 
You would be better using an accredited engineer

The signal to call for heat from the boiler comes via the three port valve.

Suggest you test the boiler call for heat by using a jumper connection
 
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If your pumps running and your boiler isn't then the fault isn't likely to be your 3 port. There's only so much we can answer on here and as you've tried the few things we've suggested I think it's time get someone in.
 

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