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www.ultimatehandyman.co.uk Forum Index -> Plumbing Forum
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gizmo71
Junior Member
Joined: 12 Nov 2007
Posts: 6
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 Posted: Wed Nov 14, 2007 9:30 pm Post subject: back boiler not firing up - doesn't stay on? |
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Dear All,
our problem is as follows: we removed one radiator from our CHS by connecting the two pipes going through it together. We then found it (thanks to your help here) that we needed to cap them off individually which we did last night. This of course meant that unfortunately some air must have entered the system (there was some in there already as we could hear it coming off when we cut the connected pipes).
Now our BAXI Bermuda back boiler (open vented system) has suddenly stopped working - even though the pilot flame is still on it doesn't fire up anymore and as a result we don't have hot water and heating (and are freezing). Anyone any ideas please?? Many thanks!!
PS: Two minutes after I finished writing this the boiler fired by itself but did not stay on for more than about a minute then turn off again?? So the problem might rather be that it does not stay on? |
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Razor
Senior Member
Joined: 14 Nov 2007
Posts: 171
Location: Northampton
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| Posted: Wed Nov 14, 2007 10:30 pm Post subject: |
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| Hi, sounds like you have an airlock, boiler is firing then going out on overheat; you may be able to bleed it by shutting off most of the radiators, (particularly downstairs), forcing the air out, the other one that gets missed is to bleed the primary coil in the airing cupboard, look for some airbleeds in there. Don't forget to bleed the pipes you capped off as well. |
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gizmo71
Junior Member
Joined: 12 Nov 2007
Posts: 6
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| Posted: Wed Nov 14, 2007 11:14 pm Post subject: |
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Hi Razor,
thanks for your fast reply. Not really sure about terminology here I am afraid... by bleeding do you mean opening the top of the radiator with a key to let out the air until some drops of water come out? If so then yes, we have done that already - however not in the two pipes we have capped off... so the problem might be there. We will try (which then means draining the system again - arrgghh) - mayb this solves the problem - could very well be.
But not sure what the primary coil is... could you clarify for us dummies please? Many thanks! (We have a 117 litre hot water tank if that is also important to know?) |
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Razor
Senior Member
Joined: 14 Nov 2007
Posts: 171
Location: Northampton
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| Posted: Wed Nov 14, 2007 11:35 pm Post subject: |
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Sorry I didn't make it clear, you can bleed your capped off pipes by gently loosening the caps until water drips out, no need to drain, in the airing cupboard by the cylinder you should find at least one short length of vertical pipe that has a fitting on the top, sort of a cap with a bit that can be unscrewed possibly looking like this;
http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100555&ts=83217&id=19155
Just undo it half a turn or so and see if air comes out, this is where I would start.
Good luck |
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tim'll fix it
BANNED
Joined: 18 Jan 2006
Posts: 2137
Location: Leicestershire
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| Posted: Thu Nov 15, 2007 12:06 am Post subject: |
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razors right
sounds like an airlock in the hot water cylinder coil to me
look for the bleed valve in the airing cupboard
also try turning the heating on and off repeated a few times sometimes will clear them too
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gizmo71
Junior Member
Joined: 12 Nov 2007
Posts: 6
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| Posted: Thu Nov 15, 2007 2:39 pm Post subject: |
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| many thanks for your replies. We will try this tonight when we get home. We bled all radiators and the capped pipes last night and the boiler turned on - but as we woke up this morning it was cold again... but we will follow your advice on the pipe in the airing cupboard too - hopefully this does the trick. Many thanks again! |
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gizmo71
Junior Member
Joined: 12 Nov 2007
Posts: 6
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| Posted: Fri Nov 16, 2007 10:14 am Post subject: |
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Dear All,
it's me again... still having trouble (and it's cold!!)
Last night we bled (and re-bled) all possible pipes, vents etc (also the one from the heating cylinder as you recommended - where a lot of air came out). The boiler keeps on firing up and heated some upstairs radiators - we have three - for a while. However, the downstairs ones were still ice cold and so was the hot water. We then turned up the temperature in the boiler to maximum (so far we had it always had it on 2.5) and then the water in the pipes really started to heat up. The radiators upstairs heated up quite quickly and became really hot. However, still no hot water - even though the pipes leading into the cylinder slowly started to become warm as well.
Even though we liked the fact that suddenly something seemed to be happening we got scared after a while as the following happened: about every 10 minutes the overflow pipe dispensed increasingly hot water into the heat-and-expansion tank on the first floor and then a whole flood of cold water was released from the heat-and-expansion tank into the system - cooling it down in seconds (as we could feel in the pipes downstairs next to the boiler). This made a very loud, rattling noise (like a waterfall in the pipes). The overflow pipe spitted so much water around the room upstairs (as the pressure seemed to increase continuously) so that we decided at one point to lower the temperature of the boiler to its original 2.5 as we were slightly scared... :o
then the boiler stopped firing up again, all radiators were cold in the morning and -of course- there is no hot water... I used the emergency heater to heat the water in the cylinder which works absolutely fine.
We are really lost now... and have the following questions:
1) can there still be air in the system and if so where else could we bleed?
2) We have a stopcockon the pipes which seem to feed the radiators upstairs - this stopcock is opened completely. Somehow we have the feeling that the fact that no hot water is going into the hot water cylinder could be related to this stopcock and how far it should be open? Could there be any relation?
3) How high should the temperature be set in a Baxi Bermuda Bacvk boiler at this time of the year?
4) How come we have (sometimes) heating but never any hot water??
The boiler still fires up from time to time (even though much less so since we have lowered the temperature) but it doesn't seem to get to the hot water tank...
As we are about to have our whole system replaced by a combi boiler in about two weeks we don't really want to get anyone in as it would be a total waste (and we live in London where people charge a fortune...). But we need to survive until then. Please help again!! many thanks!!!!!!! |
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Razor
Senior Member
Joined: 14 Nov 2007
Posts: 171
Location: Northampton
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| Posted: Fri Nov 16, 2007 10:40 am Post subject: |
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Hi,
Sounds like you still have air in the system, the hot water may well be heated by gravity circulation which means it wouldn't take a lot to stop it working, it also sounds as if the pump has suffered either from debris disturbed during the drain down or from being run dry. The pump will probably be in the same location as the gatevalve, (not stopcock), you mention or if ur unlucky it will be under the floor on the same side of the chimney breast, bleed it with the system off by unscrewing the large screw in the middle, with the system on you should be able to feel it running, check what number it's set on if you set it on max, (III), you will have more chance of clearing air from the system, did you try shutting down the valves on most of the radiators just leaving a couple upstairs for the air to go to? The water coming out of the vent pipe could just be where the airlocks are clearing, try turning it all off for a couple of hours to let things settle. 2/3 is about what most people leave these units set to.
BTW you are trying to bleed the system whilst its off and NOT on arn't you?
Your system will certainly need a powerflush b4 the new boiler is fitted or you will have a very good chance of killing the new boiler very quickly |
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Razor
Senior Member
Joined: 14 Nov 2007
Posts: 171
Location: Northampton
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| Posted: Mon Nov 19, 2007 12:30 pm Post subject: |
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| Oh Dear, wonder if they froze to death? |
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Hinton Heating
Gas/Heating Expert
Joined: 16 Jan 2006
Posts: 4296
Location: Bournemouth
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| Posted: Mon Nov 19, 2007 2:02 pm Post subject: |
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I'm now thinking the pump may be siezed, or the system just hasn'[t enough water in it (blocked cold feed, stuck ball valve)
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gizmo71
Junior Member
Joined: 12 Nov 2007
Posts: 6
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| Posted: Tue Nov 27, 2007 11:20 am Post subject: |
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| Hi Guiys, just wanted to say that we didn't freeze to death - worked out fine in the end (after we bled the system many times). Many thanks for your help here in the forum - very helpful. |
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