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#1
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replacing immersion heater
I need to replace the immersion heater in a traditional hot-water
cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water & unscrewed the old element, & am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Thanks, Adam |
#2
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replacing immersion heater
Adam Funk wrote:
I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water & unscrewed the old element, & am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Most HW cylinders will have a drain cock tucked away at the bottom somewhere but not always. It's a good idea to have the cylinder *full* of water before attempting to unscrew the old element though, it may require a lot of force and having the cylinder full of water makes it more rigid and less prone to damage. If you can't find a draincock I think you just have to shut off the supply, drain what you can and have some towels handy. You could disconect the pipework at the top and syphon water out with a hosepipe but I suspect that is overkill (assumming the element is inserted down from the shoulder at the top of the cylinder). Tim |
#3
Posted to uk.d-i-y
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replacing immersion heater
On 08/02/2012 15:08, Adam Funk wrote:
I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water& unscrewed the old element,& am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Thanks, Adam AFAIK the thread hasn't changed in a very long time. The problem with draining is that the DHW supply normally comes from the top with the cold feed to the bottom. Not usually much spillage with a top entry element; you *do* have a wet and dry vacuum cleaner, don't you? If the element is side entry at the bottom, you need to hope your plumber fitted a drain cock on the cold feed. |
#4
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replacing immersion heater
"Newshound" wrote in message ... On 08/02/2012 15:08, Adam Funk wrote: I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water& unscrewed the old element,& am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Thanks, Adam Not done one of those in years Hated the job with a passion When I did do them getting the old ones to unscrew without trashing the tank was the real challenge As to getting water out after shutting the water off this can only be done by a drain on the cold water bottom feed which was usually on the side of the tank rather that at the front. And often the airing cupboard was built around it afterwards Hot water storage tanks force the hot water out of top when a tap is opened due to the header tank being connected to the bottom Best of luck Regards |
#5
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replacing immersion heater
"TMC" wrote in message ... "Newshound" wrote in message ... On 08/02/2012 15:08, Adam Funk wrote: I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water& unscrewed the old element,& am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Thanks, Adam Not done one of those in years Hated the job with a passion When I did do them getting the old ones to unscrew without trashing the tank was the real challenge As to getting water out after shutting the water off this can only be done by a drain on the cold water bottom feed which was usually on the side of the tank rather that at the front. And often the airing cupboard was built around it afterwards Hot water storage tanks force the hot water out of top when a tap is opened due to the header tank being connected to the bottom Best of luck Regards water off at mains, drain thro hot taps till they stop. Disconnect wiring (safely), hammer and chisel and knock the edge of the nut of the heater till it moves then unscrew with immersion spanner. Refitting with a small amount of sealant on the fibre washer and nip up with spanner. Reconnect refill and check for leaks. |
#6
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replacing immersion heater
On Feb 8, 3:08*pm, Adam Funk wrote:
I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). *The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". *(The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. *Can I buy one, safe in the knowledge that the thread will be the same? *(In other words, I won't get a nasty surprise when I've drained the hot water & unscrewed the old element, & am about to try putting the one in. *I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? *Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Thanks, Adam Immersion heaters have a 2&1/4" BSP thread. With very few exceptions they have been like this for 60 years to my knowledge. There are lots of makes. As long as it's the same size (3Kw, 27"), it will be OK. The stainless steel ones last longer but cost more. The best advice is when you come to unscrew it,don't put too much pressure on the spanner. You will ripple the tank. Get a hacksaw blade, tape the end up for a handle and saw the big washer through all the way round. (You will feel it skidding on the metal when you get through.) Clean up the face of the flange before you put the new one in. Best put a bit of plumbers mate on the new washer. Fill the tank before you switch on. They last about 30 seconds without! |
#7
Posted to uk.d-i-y
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replacing immersion heater
On 08/02/2012 16:37, TMC wrote:
"Newshound" wrote in message ... On 08/02/2012 15:08, Adam Funk wrote: I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water& unscrewed the old element,& am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Thanks, Adam Not done one of those in years Hated the job with a passion When I did do them getting the old ones to unscrew without trashing the tank was the real challenge Yes, I got mine out once, but I then had to change the tank anyway, and it was impossible to get the element out a 2nd time. -- Michael Chare |
#8
Posted to uk.d-i-y
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replacing immersion heater
On 2012-02-08, Newshound wrote:
AFAIK the thread hasn't changed in a very long time. The problem with draining is that the DHW supply normally comes from the top with the cold feed to the bottom. Not usually much spillage with a top entry element; you *do* have a wet and dry vacuum cleaner, don't you? No, but I have lots of old towels and rags. ;-) I checked and the element's fitting is really close to the top of the cylinder, so even if I can't find a drain cock, I don't think a lot will run out. If the element is side entry at the bottom, you need to hope your plumber fitted a drain cock on the cold feed. I haven't found the drain cock yet, but the airing cupboard is rather tight and I haven't rummaged thoroughly. |
#9
Posted to uk.d-i-y
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replacing immersion heater
On 2012-02-08, Tim Downie wrote:
Adam Funk wrote: I need to replace the immersion heater in a traditional hot-water cylinder (with a cister and a coil heated by the boiler). The existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V AC ONLY / LENGTH 27" FIXING V". (The element was installed at least 17 years ago.) I see from googling that the Heatrae Gold Dot product in 27" size still exists. Can I buy one, safe in the knowledge that the thread will be the same? (In other words, I won't get a nasty surprise when I've drained the hot water & unscrewed the old element, & am about to try putting the one in. I'd really prefer not to have to leave everything hanging open while I cart the old element to a shop for comparison.) Also, are there any tricks for getting the water level in the cylinder below the fitting for the element? Or do I just shut off the water to the cistern, run as much water out of the hot system as I can, and then mop up what runs out when I unscrew the old element? Most HW cylinders will have a drain cock tucked away at the bottom somewhere but not always. It's a good idea to have the cylinder *full* of water before attempting to unscrew the old element though, it may require a lot of force and having the cylinder full of water makes it more rigid and less prone to damage. If you can't find a draincock I think you just have to shut off the supply, drain what you can and have some towels handy. You could disconect the pipework at the top and syphon water out with a hosepipe but I suspect that is overkill (assumming the element is inserted down from the shoulder at the top of the cylinder). Thanks. I agree about having the cylinder mostly full to keep it heavy and stable. |
#10
Posted to uk.d-i-y
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replacing immersion heater
If you can't find a draincock I think you just have to shut off the supply,
drain what you can and have some towels handy. You could disconect the pipework at the top and syphon water out with a hosepipe but I suspect that is overkill (assumming the element is inserted down from the shoulder at the top of the cylinder). Thanks. I agree about having the cylinder mostly full to keep it heavy and stable. Do go easy when you come to undoing it its very easy to rip a copper cylinder if you apply a bit too much torque to the spanner;!!... -- Tony Sayer |
#11
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replacing immersion heater: get a wet and dry vac!
On 09/02/2012 12:15, Adam Funk wrote:
On 2012-02-08, Newshound wrote: AFAIK the thread hasn't changed in a very long time. The problem with draining is that the DHW supply normally comes from the top with the cold feed to the bottom. Not usually much spillage with a top entry element; you *do* have a wet and dry vacuum cleaner, don't you? No, but I have lots of old towels and rags. ;-) I checked and the element's fitting is really close to the top of the cylinder, so even if I can't find a drain cock, I don't think a lot will run out. If the element is side entry at the bottom, you need to hope your plumber fitted a drain cock on the cold feed. I haven't found the drain cock yet, but the airing cupboard is rather tight and I haven't rummaged thoroughly. Seriously, a wet and dry vac is one of the most useful plumbing tools you can get. The plastic Wickes / Earlex cheapie is fine. Apart from your cylinder job, you can use them to empty gullies, catch the water when draining a washing machine, dry up after defrosting a freezer, empty the pan of a blocked loo, empty blocked sinks before opening the trap, catch the muck when you need to drain a radiator, to name but a few. |
#12
Posted to uk.d-i-y
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replacing immersion heater: get a wet and dry vac!
"Newshound" wrote in message ... On 09/02/2012 12:15, Adam Funk wrote: On 2012-02-08, Newshound wrote: AFAIK the thread hasn't changed in a very long time. The problem with draining is that the DHW supply normally comes from the top with the cold feed to the bottom. Not usually much spillage with a top entry element; you *do* have a wet and dry vacuum cleaner, don't you? No, but I have lots of old towels and rags. ;-) I checked and the element's fitting is really close to the top of the cylinder, so even if I can't find a drain cock, I don't think a lot will run out. If the element is side entry at the bottom, you need to hope your plumber fitted a drain cock on the cold feed. I haven't found the drain cock yet, but the airing cupboard is rather tight and I haven't rummaged thoroughly. Seriously, a wet and dry vac is one of the most useful plumbing tools you can get. The plastic Wickes / Earlex cheapie is fine. Apart from your cylinder job, you can use them to empty gullies, catch the water when draining a washing machine, dry up after defrosting a freezer, empty the pan of a blocked loo, empty blocked sinks before opening the trap, catch the muck when you need to drain a radiator, to name but a few. I have a George would not be without it |
#13
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replacing immersion heater
On 2012-02-08, harry wrote:
Immersion heaters have a 2&1/4" BSP thread. With very few exceptions they have been like this for 60 years to my knowledge. There are lots of makes. As long as it's the same size (3Kw, 27"), it will be OK. The stainless steel ones last longer but cost more. The best advice is when you come to unscrew it,don't put too much pressure on the spanner. You will ripple the tank. Get a hacksaw blade, tape the end up for a handle and saw the big washer through all the way round. (You will feel it skidding on the metal when you get through.) Clean up the face of the flange before you put the new one in. Best put a bit of plumbers mate on the new washer. Fill the tank before you switch on. They last about 30 seconds without! Thanks very much for the advice. I'll be careful! |
#14
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replacing immersion heater
On 2012-02-09, tony sayer wrote:
If you can't find a draincock I think you just have to shut off the supply, drain what you can and have some towels handy. You could disconect the pipework at the top and syphon water out with a hosepipe but I suspect that is overkill (assumming the element is inserted down from the shoulder at the top of the cylinder). Thanks. I agree about having the cylinder mostly full to keep it heavy and stable. Do go easy when you come to undoing it its very easy to rip a copper cylinder if you apply a bit too much torque to the spanner;!!... Thanks; I'll be careful... |
#15
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replacing immersion heater
In message , tony sayer
writes If you can't find a draincock I think you just have to shut off the supply, drain what you can and have some towels handy. You could disconect the pipework at the top and syphon water out with a hosepipe but I suspect that is overkill (assumming the element is inserted down from the shoulder at the top of the cylinder). Thanks. I agree about having the cylinder mostly full to keep it heavy and stable. Do go easy when you come to undoing it its very easy to rip a copper cylinder if you apply a bit too much torque to the spanner;!!... Until you get it turning, I would suggest tapping the wrench (not too hard, of course) rather than prolonged pulls or pushes (and grunts), and also a bit of 'forwards and back'. -- Ian |
#16
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replacing immersion heater
On 2012-02-21, Ian Jackson wrote:
In message , tony sayer writes If you can't find a draincock I think you just have to shut off the supply, drain what you can and have some towels handy. You could disconect the pipework at the top and syphon water out with a hosepipe but I suspect that is overkill (assumming the element is inserted down from the shoulder at the top of the cylinder). Thanks. I agree about having the cylinder mostly full to keep it heavy and stable. Do go easy when you come to undoing it its very easy to rip a copper cylinder if you apply a bit too much torque to the spanner;!!... Until you get it turning, I would suggest tapping the wrench (not too hard, of course) rather than prolonged pulls or pushes (and grunts), and also a bit of 'forwards and back'. Thanks. |
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