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JoeDavola

Fix My Boiler

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Gas boiler's acting up. When I have a shower it stops heating the water after a few minutes and I have to re-start it to get the water heating again (despite the alleged health benefits, I don't enjoy cold showers!).

When it stops heating the water there's a red warning light goes on, an exclamation mark in a triangle kinda thing. I turn it off and on, and that goes away, although it sometimes only goes away for a minute and then comes on again.

This has happened before and I think the bloke who came out to fix it said it was something to do with water pressure - from memory it wasn't a difficult fix (i.e. no specialist tools), but would the hive mind here know how I could go about fixing this myself?

Here's a photo of the boiler:

 

boiler.JPG

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Posted (edited)

It could be the bit the water goes through. The heat exchange. It'll be clogged up with shite from your system.
Possibly.
Depends where it is whether it's easy to take out and clean and put back in. It's water side not gas but I'd suggest if you're not competant then ring a man up.

If it's water pressure you need to up the water pressure. Which means fucking about with a bucket marked at 4.5l and a stopwatch set for 30 seconds and then a lifetime of ringing the water board

Edited by sarahbell

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Posted (edited)
5 minutes ago, JoeDavola said:

Gas boiler's acting up. When I have a shower it stops heating the water after a few minutes and I have to re-start it to get the water heating again (despite the alleged health benefits, I don't enjoy cold showers!).

When it stops heating the water there's a red warning light goes on, an exclamation mark in a triangle kinda thing. I turn it off and on, and that goes away, although it sometimes only goes away for a minute and then comes on again.

This has happened before and I think the bloke who came out to fix it said it was something to do with water pressure - from memory it wasn't a difficult fix (i.e. no specialist tools), but would the hive mind here know how I could go about fixing this myself?

Here's a photo of the boiler:

 

boiler.JPG

Check the boiler water pressure, there's a balance valve somewhere to re-pressureise it. It should be 1 to 2 bar https://www.corgihomeplan.co.uk/help-and-advice/advice/re-pressurising-your-boiler

Edited by Option5

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Does it also run the fault when you run your hot tap full blast?

1 minute ago, Option5 said:

Check the boiler water pressure, there's a balance valve somewhere to re-pressureise it. It should be 1 to 2 bar https://www.corgihomeplan.co.uk/help-and-advice/advice/re-pressurising-your-boiler

Isn't that just for the radiator side of things? The fault would be permanently on, rather than just when showering?

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12 minutes ago, sarahbell said:

It could be the bit the water goes through. The heat exchange. It'll be clogged up with shite from your system.
Possibly.
Depends where it is whether it's easy to take out and clean and put back in. It's water side not gas but I'd suggest if you're not competant then ring a man up.

If it's water pressure you need to up the water pressure. Which means fucking about with a bucket marked at 4.5l and a stopwatch set for 30 seconds and then a lifetime of ringing the water board

Or a lady! Shame on you!

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14 minutes ago, LC1 said:

Does it also run the fault when you run your hot tap full blast?

Isn't that just for the radiator side of things? The fault would be permanently on, rather than just when showering?

Maybe it's at that point where only when the shower goes on it causes issues ? 

Would Def fiddle with the bars - even I can do that and I'm no handyman !!

Joe - just Google your boiler model and type in pressure - someone will have given instructions before or even made a video. 

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Too many things interacting in a combi boiler to say what is wrong (venturi, flow sensors, etc). Download the manual from the internet then follow the fault diagnosis flowchart.

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Does sound like a pressure fault. Or a failing temperature sensor.

The landlords replaced the ageing boiler with a new one about two years ago. After just 9 months it needed a new circuit board.

Prior to that it was doing something quite similar. This is a very hard water area and that basically kills everything.

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19 minutes ago, LC1 said:

Does it also run the fault when you run your hot tap full blast?

Isn't that just for the radiator side of things? The fault would be permanently on, rather than just when showering?

The hot water is just a branch of the same system as the radiators except it's a water/water heat exchanger. The boiler is a closed system.

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20 minutes ago, LC1 said:

Does it also run the fault when you run your hot tap full blast?

Isn't that just for the radiator side of things? The fault would be permanently on, rather than just when showering?

Yes the hot tap test or hot tap on plus shower, see if you can find any correlation with water flow / level of demand.

Yes, upping the pressure, heating side of things will be the one where you can set the appropriate pressure.

Make / Product Code of the boiler might help diagnose if service manual can be found online somewhere.

1 minute ago, Option5 said:

The hot water is just a branch of the same system as the radiators except it's a water/water heat exchanger. The boiler is a closed system.

Oh OK, so just one main heating loop through the boiler. What happens then if you turn heating on at same time as hot water demand.

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2 minutes ago, onlyme said:

What happens then if you turn heating on at same time as hot water demand.

Usually hot water takes priority through the diverter valve as it's instant demand, heating just takes a bit longer to warm up.

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1 minute ago, Option5 said:

Usually hot water takes priority through the diverter valve as it's instant demand, heating just takes a bit longer to warm up.

More wondering whether the fault light comes up.

Another idea - unscrew the shower rose, try the shower with just the outlet hose and see if continues running without fault. One thing that can and does change is furring up of the shower head/rose, loss of flow here I'm guessing might be leading to an overtemp situation in the boiler / heat exchanger if it is not regulating properly and needs a certain flow rate.

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Posted (edited)
4 minutes ago, onlyme said:

Another idea - unscrew the shower rose, try the shower with just the outlet hose and see if continues running without fault. One thing that can and does change is furring up of the shower head/rose, loss of flow here I'm guessing might be leading to an overtemp situation in the boiler / heat exchanger if it is not regulating properly and needs a certain flow rate.

I'll try the kitchen tap, as I think that sometimes causes the same issue. Might help rule out the shower issue.

Thanks for the replies everyone - found the front panel as well which would indicate that the model number is isofast f28.

Edited by JoeDavola

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17 minutes ago, JoeDavola said:

I'll try the kitchen tap, as I think that sometimes causes the same issue. Might help rule out the shower issue.

Thanks for the replies everyone - found the front panel as well which would indicate that the model number is isofast f28.

 

Manual. Page 29 tells you how to find fault codes on the boiler itself.

https://letsfixit.co.uk/wp-content/uploads/ISOFAST.pdf

 

 

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Posted (edited)
1 hour ago, The Masked Tulip said:

Sounds like a pressure problem as others have stated - running the shower drops the pressure, probably because the pressure is already too low.

There are loads of videos on YouTube showing how to repressurise if you have a combi boiler.

https://www.youtube.com/results?search_query=gas+boiler+repressurise

The shower will be on the hot water circuit. This has nothing to do with the pressure in the heating circuit (in other words, nothing to do with 'repressurising the boiler')

Edited by Panther

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Just now, Panther said:

The shower will be on the hot water circuit. This has nothing to do with the pressure in the heating circuit. In other words, nothing to do with 'repressurising the boiler'

The boiler closed loop heating circuit is the one that needs pressure, the mains water pressure has nothing to do with it. A diverter valve usually controls whether the hot water from the boiler heats the radiators or the hot water. The boiler doesn't directly heat the hot water, it's a water/water heat exchanger.

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4 minutes ago, Panther said:

The shower will be on the hot water circuit. This has nothing to do with the pressure in the heating circuit (in other words, nothing to do with 'repressurising the boiler')

The above wouldn't be the case if it's not an electric shower though ? 

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Just now, ccc said:

The above wouldn't be the case if it's not an electric shower though ? 

No that's an element in a small pressure tank, think powerful kettle with a sealed lid.

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Posted (edited)
20 minutes ago, ccc said:

The above wouldn't be the case if it's not an electric shower though ? 

The above *is* the case when it is not an electric shower. An electric shower is completely independent of any combi boiler, it is cold water that is plumbed into an electric shower (though I am sure some bodger has plumbed hot water into an electric shower at some point)

Edited by Panther

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