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worcester bosch boiler pressure
I have a worcester bosch boiler, whose pressure dial is all over the
place. Sometimes it's at close to zero in the red zone, sometimes it's just in the green zone. It's been behaving this way for many months. Is this a problem with worcester bosch boilers in particular, or boilers in general? When we get a British Gas engineer to fix it, he increases the pressure so it's in the green zone. After a few weeks it's fallen again into the red zone. The boiler is ten years old. Can it be fixed? Should I be looking at a new boiler? Apart from the pressure dial, the boiler is fine. |
worcester bosch boiler pressure
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worcester bosch boiler pressure
On 17/11/2020 21:08, AJH wrote:
On 17/11/2020 20:31, wrote: I have a worcester bosch boiler, whoseÂ* pressure dial is all over the place. Sometimes it's at close to zero in the red zone, sometimes it's just in the green zone. It's been behaving this way for many months. Is this a problem with worcester bosch boilers in particular, or boilers in general? When we get a British Gas engineer to fix it, he increases the pressure so it's in the green zone. After a few weeks it's fallen again into the red zone. The boiler is ten years old. Can it be fixed? Should I be looking at a new boiler? Apart from the pressure dial, the boiler is fine. It's probably a failed expansion vessel That would be my guess too, or perhaps it just needs topping up? Ever since I had an old Vaillant getting on for 30 years ago where the vessel was totally inaccessible, I have had an external one on my system. Modern stuff seems to be much better designed for servicing. If you are half handy with DIY, it may not be difficult to remove the outer casing, then it is just a question of unscrewing the valve cap (if water comes out, the diaphragm has failed), attaching a bicycle pump and pumping it up to 20 psi or so (you will need to look that up). You should be able to do all that without doing anything like disturbing gas or opening the combustion chamber. You imply that you never need to top it up. Also maybe worth taping a clear polythene bag over the external overflow and checking after a few days whether any water has come out. |
worcester bosch boiler pressure
In message , AJH
writes On 17/11/2020 20:31, wrote: I have a worcester bosch boiler, whose pressure dial is all over the place. Sometimes it's at close to zero in the red zone, sometimes it's just in the green zone. It's been behaving this way for many months. Is this a problem with worcester bosch boilers in particular, or boilers in general? When we get a British Gas engineer to fix it, he increases the pressure so it's in the green zone. After a few weeks it's fallen again into the red zone. The boiler is ten years old. Can it be fixed? Should I be looking at new boiler? Apart from the pressure dial, the boiler is fine. It's probably a failed expansion vessel Certainly old enough. Pressure vessels/system pressure has been exercising my mind lately (never mind the just discovered manifold drip). While the system was out of use, I checked the expansion vessel pressure. Around 7.5psi but with a slight dribble of water. Pumped up to around 1 bar. Room temp to full system heat gives a pressure rise of around 0.8 bar so within reasonable limits. However the slight drip has made me aware how sensitive this set up is to system water volume changes. My inclination is to reduce the expansion vessel pressure to say 0.8bar (static head in a chalet bungalow not an issue) and the room temp. system pressure to say 1.2 bar. This would use up some of the available expansion volume but make the system more stable. As has been said elsewhere before, I should really fit an additional expansion vessel! -- Tim Lamb |
worcester bosch boiler pressure
On 17/11/2020 23:33, John Rumm wrote:
that causes the emergency pressure reduction valve to dump some water out of the blow off pipe outside IME once one of these cracks open at over pressure they do not reseal well and continually leak slightly thereafter. |
worcester bosch boiler pressure
In message , AJH
writes On 17/11/2020 23:33, John Rumm wrote: that causes the emergency pressure reduction valve to dump some water out of the blow off pipe outside IME once one of these cracks open at over pressure they do not reseal well and continually leak slightly thereafter. Oh! That's a bit worrying. I suspect mine has been opening due to water hammer when the changeover valve operated. I have put in a relief valve set at around 0.8 bar shunting the boiler output through the DHW coil and then back to the boiler. -- Tim Lamb |
worcester bosch boiler pressure
On 18/11/2020 10:23, AJH wrote:
On 17/11/2020 23:33, John Rumm wrote: that causes the emergency pressure reduction valve to dump some water out of the blow off pipe outside IME once one of these cracks open at over pressure they do not reseal well and continually leak slightly thereafter. Yup can happen - although probably more likely if it does it a few times and can get a chance to scale up. (and if its happing often that also suggests more top up water, less inhibitor and more scale in the first place just to compound things). -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
worcester bosch boiler pressure
On 18/11/2020 10:23, AJH wrote:
On 17/11/2020 23:33, John Rumm wrote: that causes the emergency pressure reduction valve to dump some water out of the blow off pipe outside IME once one of these cracks open at over pressure they do not reseal well and continually leak slightly thereafter. That's been my experience too |
worcester bosch boiler pressure
On Tue, 17 Nov 2020 21:08:58 +0000, AJH
wrote: On 17/11/2020 20:31, wrote: I have a worcester bosch boiler, whose pressure dial is all over the place. Sometimes it's at close to zero in the red zone, sometimes it's just in the green zone. It's been behaving this way for many months. Is this a problem with worcester bosch boilers in particular, or boilers in general? When we get a British Gas engineer to fix it, he increases the pressure so it's in the green zone. After a few weeks it's fallen again into the red zone. The boiler is ten years old. Can it be fixed? Should I be looking at a new boiler? Apart from the pressure dial, the boiler is fine. It's probably a failed expansion vessel When the British Gas engineer visited recently, he said something about "capillary". Basically the pressure dial drops well into the red zone, and when you tap it, it goes up into the green zone. Would that be a problem with the dial itself, "capillary" or whatever, or would it be a faulty expansion vessel? |
worcester bosch boiler pressure
On 21/11/2020 20:53, wrote:
On Tue, 17 Nov 2020 21:08:58 +0000, AJH wrote: On 17/11/2020 20:31, wrote: I have a worcester bosch boiler, whose pressure dial is all over the place. Sometimes it's at close to zero in the red zone, sometimes it's just in the green zone. It's been behaving this way for many months. Is this a problem with worcester bosch boilers in particular, or boilers in general? When we get a British Gas engineer to fix it, he increases the pressure so it's in the green zone. After a few weeks it's fallen again into the red zone. The boiler is ten years old. Can it be fixed? Should I be looking at a new boiler? Apart from the pressure dial, the boiler is fine. It's probably a failed expansion vessel When the British Gas engineer visited recently, he said something about "capillary". Basically the pressure dial drops well into the red zone, and when you tap it, it goes up into the green zone. Would that be a problem with the dial itself, "capillary" or whatever, or would it be a faulty expansion vessel? Sounds like a sticky needle in the dial gauge. If it were the faulty expansion vessel the pressure would drop below the point at which a pressure switch would prevent the boiler from firing. |
worcester bosch boiler pressure
On Sun, 22 Nov 2020 15:49:25 +0000, AJH
wrote: It's probably a failed expansion vessel When the British Gas engineer visited recently, he said something about "capillary". Basically the pressure dial drops well into the red zone, and when you tap it, it goes up into the green zone. Would that be a problem with the dial itself, "capillary" or whatever, or would it be a faulty expansion vessel? Sounds like a sticky needle in the dial gauge. If it were the faulty expansion vessel the pressure would drop below the point at which a pressure switch would prevent the boiler from firing. How would it be fixed? Can you replace the dial gauge, would that solve it? |
worcester bosch boiler pressure
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worcester bosch boiler pressure
On 29/11/2020 20:25, wrote:
On Fri, 27 Nov 2020 19:52:57 +0000, wrote: On Sun, 22 Nov 2020 15:49:25 +0000, AJH wrote: It's probably a failed expansion vessel When the British Gas engineer visited recently, he said something about "capillary". Basically the pressure dial drops well into the red zone, and when you tap it, it goes up into the green zone. Would that be a problem with the dial itself, "capillary" or whatever, or would it be a faulty expansion vessel? Sounds like a sticky needle in the dial gauge. If it were the faulty expansion vessel the pressure would drop below the point at which a pressure switch would prevent the boiler from firing. How would it be fixed? Can you replace the dial gauge, would that solve it? Just replace the dial gauge? Is it that simple? If its just a faulty gauge, then yes. If its something else, then no. If tapping the gauge causes it to change reading, then its a good indication the gauge itself is the problem. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
worcester bosch boiler pressure
On 29/11/2020 20:25, wrote:
On Fri, 27 Nov 2020 19:52:57 +0000, wrote: On Sun, 22 Nov 2020 15:49:25 +0000, AJH wrote: It's probably a failed expansion vessel When the British Gas engineer visited recently, he said something about "capillary". Basically the pressure dial drops well into the red zone, and when you tap it, it goes up into the green zone. Would that be a problem with the dial itself, "capillary" or whatever, or would it be a faulty expansion vessel? Sounds like a sticky needle in the dial gauge. If it were the faulty expansion vessel the pressure would drop below the point at which a pressure switch would prevent the boiler from firing. How would it be fixed? Can you replace the dial gauge, would that solve it? Just replace the dial gauge? Is it that simple? Do nothing and just tap it when you look at it seems simpler |
worcester bosch boiler pressure
On Tue, 17 Nov 2020 23:33:02 +0000, John Rumm
wrote: It sounds like this is not a fault with the dial- its probably telling you the truth. Its more likely that the system is losing pressure over time for some reason. The boiler is ten years old. Can it be fixed? Probably Should I be looking at a new boiler? Not if that is the only faulr Apart from the pressure dial, the boiler is fine. I expect the pressure dial is fine, and you either have a system leak, or a non working expansion vessel. With a leak, you would expect the pressure dial to act fairly normally - rising a bit as the system warms up, and falling back to where it started as it cools - however you may see a steady drop over a period. If its an expansion vessel problem then the pressure change will be much larger, swinging very high as the system heats, that causes the emergency pressure reduction valve to dump some water out of the blow off pipe outside. Then as the boiler cools it dropping to a much lower pressure than when it started. We had a British Gas engineer a couple of days ago, and he said the loss of pressure over a period of two or three months is natural, that the boiler needs to be topped up every two or three months, and not to worry about it. Is he right? I'm not into this stuff, should I worry? |
worcester bosch boiler pressure
On 05/06/2021 20:58, wrote:
On Tue, 17 Nov 2020 23:33:02 +0000, John Rumm wrote: It sounds like this is not a fault with the dial- its probably telling you the truth. Its more likely that the system is losing pressure over time for some reason. The boiler is ten years old. Can it be fixed? Probably Should I be looking at a new boiler? Not if that is the only faulr Apart from the pressure dial, the boiler is fine. I expect the pressure dial is fine, and you either have a system leak, or a non working expansion vessel. With a leak, you would expect the pressure dial to act fairly normally - rising a bit as the system warms up, and falling back to where it started as it cools - however you may see a steady drop over a period. If its an expansion vessel problem then the pressure change will be much larger, swinging very high as the system heats, that causes the emergency pressure reduction valve to dump some water out of the blow off pipe outside. Then as the boiler cools it dropping to a much lower pressure than when it started. We had a British Gas engineer a couple of days ago, and he said the loss of pressure over a period of two or three months is natural, that the boiler needs to be topped up every two or three months, and not to worry about it. Is he right? I'm not into this stuff, should I worry? If it has been recently drained and refilled (or its a completely new system) then there will be a fair amount of air dissolved in the water. This will tend to come out of suspension and accumulate in a radiator somewhere. When you bleed that rad, you will drop the pressure a bit and may need to top up. However once a system has been running a while and the the water is basically stagnant, then it ought not change much or at all. It is possible to have tiny leaks in a system - so slow the water evaporates before you ever see it. This is generally not a problem if you only need top up once or twice a year. Although you should periodically add some extra corrosion inhibitor since it will get diluted over time, and the fresh oxygen introduced each time you top up needs to be "mopped up" by the oxygen scavenger in the inhibitor which will get used up by the fresh water being introduced. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
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