Central heating issue (but not on boat)

[starman]

I thought I’d ask this because I know we have at least one ch expert here. 

We have a Grant combi oil boiler; the hot water side is fine but the ch is giving problems. It won’t come on but there’s obviously some heating going on as the return pipe is hot while The flow isn’t. Presumably the pump isn’t working. Also I can’t hear any ‘click’ from the boiler thermostat. 

However if I switch the boiler off then on again, the pump runs and the heating works fine. 

Any suggestions on what’s wrong? 

[Ian F B]

Do a factory reset,most boilers have this option,then reset to your requirements,had any power cuts lately?This can cause a glitch!???

[jonathanA]

Check the pressure in the heating circuit and top up if required. Although your symptoms don’t sound like it’s that but it’s the obvious thing to check for starters

[MtB]

4 hours ago, starman said:

I thought I’d ask this because I know we have at least one ch expert here. 

 

As he's not around, I'll have a bash instead.

 

 

4 hours ago, starman said:

It won’t come on but there’s obviously some heating going on as the return pipe is hot while The flow isn’t. Presumably the pump isn’t working. Also I can’t hear any ‘click’ from the boiler thermostat. 

However if I switch the boiler off then on again, the pump runs and the heating works fine. 

Any suggestions on what’s wrong? 

 

Difficult to comment without knowing which Grant combi boiler you have, exactly. Most boilers will have a fault-tracing section (often with flow chart) in the manual. Have you had a read to see what it says? 

[Tony Brooks]

11 hours ago, Ian F B said:

Do a factory reset,most boilers have this option,then reset to your requirements,had any power cuts lately?This can cause a glitch!???

Agreed. If I leave my home central heating with the sliders on the controller set to off but the system powered up while I am on the boat for the summer it seems to exhibit very similar symptoms to yours until I turn the whole system off at the mains for a few minutes, but as Mike says if you have the manuals look at the fault finding chart.

[WotEver]

17 minutes ago, Tony Brooks said:

... as Mike says if you have the manuals look at the fault finding chart.

And if you don’t have the manual I’m sure it’ll be available for download somewhere. 

[starman]

8 hours ago, Mike the Boilerman said:

 

As he's not around, I'll have a bash instead.

 

 

 

Difficult to comment without knowing which Grant combi boiler you have, exactly. Most boilers will have a fault-tracing section (often with flow chart) in the manual. Have you had a read to see what it says? 

It’s a Vortex Combi 21 Mike. I have got a manual but the flow chart is really for blokes like you who have the nous to understand it not simple souls like me. 

The system had been working since its summer break but just stopped. There’s heat being produced but the boilers ch pump is stopped.  Switching the boiler off and on sometimes gets it all going again. Also no audible ‘click’ on the boiler thermostat. All suggests some faulty sensor maybe. 

I think I’ll have to get our local MtB in?

[MtB]

7 minutes ago, starman said:

It’s a Vortex Combi 21 Mike. I have got a manual but the flow chart is really for blokes like you who have the nous to understand it not simple souls like me. 

The system had been working since its summer break but just stopped. There’s heat being produced but the boilers ch pump is stopped.  Switching the boiler off and on sometimes gets it all going again. Also no audible ‘click’ on the boiler thermostat. All suggests some faulty sensor maybe. 

I think I’ll have to get our local MtB in?

 

 

Ok. Just had a quick scan at the manual. I see there is a "CH pump" indicator light on the front panel. Is this failing to illuminate? Is this how you know the CH pump is not running?

[starman]

6 minutes ago, Mike the Boilerman said:

 

 

Ok. Just had a quick scan at the manual. I see there is a "CH pump" indicator light on the front panel. Is this failing to illuminate? Is this how you know the CH pump is not running?

I don’t think there is on mine. I have the boiler casing off and I can feel the pump. Also the water pipe  on the supply side is hot and the other side into the ch circuits   cold - do a bit of main switch flicking and it starts running and then the boiler fires. The overheat button doesn’t come on.

Edited November 19, 2018 by starman

[MtB]

Just now, starman said:

I don’t think there is on mine. I have the boiler casing off and I can feel the pump. Also the water pipe  on the supply side is hot and the other side cold - do a bit of main switch flicking and it starts running and then the boiler fires. The overheat button doesn’t come on.

 

Ok. I was looking at the manual for the Vortex Combi 21e, not being able to find any reference to a Vortex Combi 21.

 

Is yours definitely a Vortex Combi 21?

 

 

And from what you say, yes the CH pump is not running. The task is to find out why! If there is an indicator light and it is OFF, this tells us the boiler isn't sending it power. If it is ON, then there is probably power and the pump itself has stuck or failed. 

[starman]

2 minutes ago, Mike the Boilerman said:

 

Ok. I was looking at the manual for the Vortex Combi 21e, not being able to find any reference to a Vortex Combi 21.

 

Is yours definitely a Vortex Combi 21?

 

That's what it says on the can ? 'Vortex Condensing Combi 21' - the manual is a supplement to the main book of words for the Combi V3, Combi Max and Combi 26 + 36.

 

BTW at the moment flipping the on/off switch cajoles the boiler to start, it runs for 5-10 mins then stops.

[MtB]

20 minutes ago, starman said:

That's what it says on the can ? 'Vortex Condensing Combi 21' - the manual is a supplement to the main book of words for the Combi V3, Combi Max and Combi 26 + 36.

 

BTW at the moment flipping the on/off switch cajoles the boiler to start, it runs for 5-10 mins then stops.

 

Ok I've checked again and found a manual for a plain 21. It still has the "CH pump" light you say is missing from yours. Have a look at page 5 here: https://www.grantuk.com/media/3011/grant-vortex-pro-internal-combi-low-nox-doc-0122-rev-11.pdf

 

Look at the diagram showing the indicator lights. We need to know if firstly I am looking at the right boiler, and if I am, whether the CH pump light is ON or OFF while the pump is not working. 

[starman]

11 minutes ago, Mike the Boilerman said:

 

Ok I've checked again and found a manual for a plain 21. It still has the "CH pump" light you say is missing from yours. Have a look at page 5 here: https://www.grantuk.com/media/3011/grant-vortex-pro-internal-combi-low-nox-doc-0122-rev-11.pdf

 

Look at the diagram showing the indicator lights. We need to know if firstly I am looking at the right boiler, and if I am, whether the CH pump light is ON or OFF while the pump is not working. 

Oddly, the 21 definitely doesn't have these but the 'supplementary manual' for the 15/21 models doesn't have a different wiring diagram either. All I have on mine is basic on/off/timed ch switch, low pressure cut-out light, overheat cut-out light, system pressure gauge and heating thermostat control. The programmer is a remote wired one.

[starman]

3 minutes ago, starman said:

Oddly, the 21 definitely doesn't have these but the 'supplementary manual' for the 15/21 models doesn't have a different wiring diagram either. All I have on mine is basic on/off/timed ch switch, low pressure cut-out light, overheat cut-out light, system pressure gauge and heating thermostat control. The programmer is a remote wired one.

 

20 minutes ago, Mike the Boilerman said:

 

Ok I've checked again and found a manual for a plain 21. It still has the "CH pump" light you say is missing from yours. Have a look at page 5 here: https://www.grantuk.com/media/3011/grant-vortex-pro-internal-combi-low-nox-doc-0122-rev-11.pdf

 

Look at the diagram showing the indicator lights. We need to know if firstly I am looking at the right boiler, and if I am, whether the CH pump light is ON or OFF while the pump is not working. 

I believe this is mine:

vortex-1521-utility-and-outdoor-module-combi-21-and-outdoor-combi-21-supplement-doc38-rev02-january-2007-1.pdf

[MtB]

2 minutes ago, starman said:

Oddly, the 21 definitely doesn't have these but the 'supplementary manual' for the 15/21 models doesn't have a different wiring diagram either. All I have on mine is basic on/off/timed ch switch, low pressure cut-out light, overheat cut-out light, system pressure gauge and heating thermostat control. The programmer is a remote wired one.

 

Ok so it looks as though the documentation cannot be trusted. Quite common in oil boilers but not in gas. 

 

So the missing light just means you're gonna have to get the multimeter out and start testing stuff. Or use a 'volt stick' if you have one. 

 

Assuming the boiler is still broadly the same, the boiler powers the pump in this case, so we need to know if the pump is receiving 240Vac during its 'failed' condition. Use your volt stick to test for this or whip the top off and poker in there with your multimeter probes!

[Richard10002]

What's a volt stick?

[MtB]

3 minutes ago, starman said:

 

I believe this is mine:

vortex-1521-utility-and-outdoor-module-combi-21-and-outdoor-combi-21-supplement-doc38-rev02-january-2007-1.pdf

 

I'm afraid that's only half a link....

1 minute ago, Richard10002 said:

What's a volt stick?

 

http://bfy.tw/Kvk6

[WotEver]

1 minute ago, Richard10002 said:

What's a volt stick?

https://www.screwfix.com/p/fluke-1ac-ii-voltage-detector-pen/85949?tc=JT6&ds_kid=92700022885042733&ds_rl=1241687&ds_rl=1245250&ds_rl=1244066&ds_rl=1249796&ds_rl=1245250&ds_rl=1249481&gclid=Cj0KCQiA28nfBRCDARIsANc5BFAtarzJV9roOosPrnr9qOEmVTpIWG_UPmQtyiQuAO1VZI5NXTquf_8aAsHUEALw_wcB&gclsrc=aw.ds

[MtB]

1 minute ago, WotEver said:

https://www.screwfix.com/p/fluke-1ac-ii-voltage-detector-pen/85949?tc=JT6&ds_kid=92700022885042733&ds_rl=1241687&ds_rl=1245250&ds_rl=1244066&ds_rl=1249796&ds_rl=1245250&ds_rl=1249481&gclid=Cj0KCQiA28nfBRCDARIsANc5BFAtarzJV9roOosPrnr9qOEmVTpIWG_UPmQtyiQuAO1VZI5NXTquf_8aAsHUEALw_wcB&gclsrc=aw.ds

 

spoilsport!

 

[starman]

3 minutes ago, Mike the Boilerman said:

 

I'm afraid that's only half a link....

 

http://bfy.tw/Kvk6

Sorry about that: Grant Vortex 1521 Utility and Outdoor Module, Combi 21 and Outdoor Combi 21 supplement - DOC38 Rev02 - January 2007

1 minute ago, Mike the Boilerman said:

 

spoilsport!

 

I thought it was a wet finger! (I haven't got one - volt stick that is - just a multimeter)

[WotEver]

3 minutes ago, starman said:

I thought it was a wet finger!

That would be every bit as efficient and cheaper to boot. 

[MtB]

6 minutes ago, starman said:

Sorry about that: Grant Vortex 1521 Utility and Outdoor Module, Combi 21 and Outdoor Combi 21 supplement - DOC38 Rev02 - January 2007

 

 

Ok. Not getting very far here. No wiring diagram or any proper technical info in that document so I'm still none the wiser.

 

My gut feeling is the pump is fine so we need to find out where it gets its electricity from, as this is where the fault lies. 

[OldGoat]

14 minutes ago, WotEver said:

https://www.screwfix.com/p/fluke-1ac-ii-voltage-detector-pen/85949?tc=JT6&ds_kid=92700022885042733&ds_rl=1241687&ds_rl=1245250&ds_rl=1244066&ds_rl=1249796&ds_rl=1245250&ds_rl=1249481&gclid=Cj0KCQiA28nfBRCDARIsANc5BFAtarzJV9roOosPrnr9qOEmVTpIWG_UPmQtyiQuAO1VZI5NXTquf_8aAsHUEALw_wcB&gclsrc=aw.ds

Gosh! - I thought there was only AC or DC voltages; now we have categories as well........ 

[WotEver]

1 minute ago, OldGoat said:

Gosh! - I thought there was only AC or DC voltages; now we have categories as well........ 

Categories are better than doggerels. 

[starman]

17 minutes ago, Mike the Boilerman said:

 

Ok. Not getting very far here. No wiring diagram or any proper technical info in that document so I'm still none the wiser.

 

My gut feeling is the pump is fine so we need to find out where it gets its electricity from, as this is where the fault lies. 

I think so too but I'll have to test later as the damned thing has decided to work properly now. Was doing this before - working for a few minutes then stopping but eventually working correctly.

Maybe there's a clue in the fact that the 'heating thermostat' on the boiler doesn't click any more but that might be a fault elsewhere of course.