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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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Central Heating problem - 2A fuse blowing in honeywell wiring box
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Central Heating problem - 2A fuse blowing in honeywell wiring box
"Charlie" wrote in message om... Hello, I have a Honeywell wiring box into which all the components of my CH system are wired. In the last couple of days the 2A fuse in this box has blown (twice) and a 3A one also blew - obviously I have a problem. The pilot light is still on. There are no signs of leaks. Presumably it could be any of the components but presumably likely to be the pump or the motorised value. I've had this twice and both times it was a failing synchron motor (not yet failed) in the zone valve. Might be an idea to get a spare synchron motor if you havn't got one. Were fairly cheap from BES, now you have to pay postage. I would first check if you have separate mains feeds to boiler and wiring box. If separate I would not suspect boiler or pump initially. The intermittency may just be due to the actual current being drawn. Don't have the tables to hand but depending on the actual current the fuse may take some time to blow. If you are confident (and competent) I would suggest inserting a test meter on ac Amps in series with each load (zone valve(s), pump, boiler etc). Obligatory health warning - switch-off while connecting. What I might do in this situation is to fit a 13A plug (3A fuse) to the feed and plug into a 30mA RCD. Healthy readings should be nowhere near 3A. OK, won't work if it is genuinely an intermittent, but I would suspect not. Cost of Plumber? Sorry d-i-y here, you can buy a lot of pumps, zone valves, test meters etc for the cost of a plumber. Alan |
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Central Heating problem - 2A fuse blowing in honeywell wiring box
On Wed, 17 Sep 2003 22:00:23 +0100, "John Stumbles"
] wrote: Anyone remember the old Hornby Dublo train set controller box which had some special bulb in series with the transformer output, so that if you overloaded or shorted it the bulb would light up but in normal operation the bulb would quietly (or invisibly) pass current to the load? You might need to post this in alt.geriatric.trainlovers PoP |
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Central Heating problem - 2A fuse blowing in honeywell wiring box
I would first check if you have separate mains feeds to boiler and wiring
box. If separate I would not suspect boiler or pump initially. The intermittency may just be due to the actual current being drawn. Don't have the tables to hand but depending on the actual current the fuse may take some time to blow. If you are confident (and competent) I would suggest inserting a test meter on ac Amps in series with each load (zone valve(s), pump, boiler etc). Obligatory health warning - switch-off while connecting. What I might do in this situation is to fit a 13A plug (3A fuse) to the feed and plug into a 30mA RCD. Healthy readings should be nowhere near 3A. OK, won't work if it is genuinely an intermittent, but I would suspect not. *********UPDATE********* Had a bit of time today so this is what I did. Got a card of fuse wire - cheaper than 50p a go fuses, even if a bit fiddly!! I turned off the power and replaced the fuse. I disconnected the red wire feed to the pump in the wiring box. I set the programmer to off for both CH and HW and turned the power back on. All ok so far. I then switched the programmer to call for HW, still ok. I then switched the programmer to also call for CH, still ok. Eureka I'm thinking...it must be the pump - Grungfos 15-50. Based on a previous post I tried to get hold of a replacement capacitor but no luck. Decided I'll replace the pump, on the basis that even if it isn't the pump this time at least I'll have a replacement next time. I turned off the gate valves eitherside of the pump and tried to remove the pump. Unfortunately I didn't have large enough spanners to remove one side of the pump so reconnected to pipework again. What I didn't realise was that whilst I had the gate values on either side of the pump disconnected, the boiler couldn't come on. Presumably this means I have a fully pumped system? Anyway I decided to leave the pump disconnected this evening and try again tomorrow. Bear in mind that at this time I'm still thinking its the pump. The boiler was on and happily heating water and approximately 40mins to an hour later the fuse went pop again. When I was in the plumbers merchants he said if the pump was gone it would smell of burning - it doesn't. So now where do I stand? Have I confirmed it ISN'T the pump? Does the fact that it took 40mins to an hour to blow indicate the blowout happened when the motorised valve was moving to a different position once the HW was heated? Back to you boys ot there. Charlie And it was ok foabout 40minutes. The fuse then |
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Central Heating problem - 2A fuse blowing in honeywell wiring box
When I opened the inspection at the front of the pump I got quite a
bit of water coming out of it, as opposed to a few drips. Is this normal or does it indicate a knackered pump? I put a screw driver in to try and turn it but nothing. Didn't have a torch so unsure whether I was seating the screwdriver correctly. Took the motorised valve apart - there is very little movement. when I turn the valve but about the same as the amount of movement in the motor. However when the motorised part was off and I slid the manual overide lever across to manual, I got a consistent amount of resistence and the lever comes back ALL the way to "Auto". But when the motor and valve are back together the lever can be moved over and back by about 1cm without any resistence. Is this normal? And finally I opened the drain valve to drain the system and "NOTHING". There doesn't appear to be any water in the system. Presumably no water would cause overheating of the pump. Could this blow the 2A fuse in the wiring box or could other parts overheat? Cheers Charlie |
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Central Heating problem - 2A fuse blowing in honeywell wiring box
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Central Heating problem - 2A fuse blowing in honeywell wiring box
False alarm - there is water in the system - must be an old drain
cock. Tried again today with the red wire feeding the pump switched out and the valve manually turned on but it blew. Valve obviously kicked in cos when I checked after the blow the vavle had retiurned to the auto position. Tried with the valve feeds all out also also blew. Did manage to get it going for a short while but then the boiler went out. Managed to restart the pilot ok. I've given up!!! Charlie |
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Pulling cabling through
Had the Electrician in. None of my components had gone!!! It turned
out there is a break in the cable running from under the stairs to the kitchen. About 15 metres of cable nicely boxed and hidden. I did it myself around 15 years ago so I can't complain too much!! Now my problem is do I run a new cable in some sticky back trunking along the skirting and behind the kitchen cupboards where it can be seen (concrete floors unfortunately) or do I try and pull a new cable thru the existing boxing which also contains the pipework? I previously used twin and earth lighting cable. Electrician suggested I use 4 core as a replacement as any future boiler is likely to have live in addition to switched live. Will the new cable be up to being pulled through about 15metres of boxing, 2 walls and 3 corners. Cheers Charlie |
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Pulling cabling through
In uk.d-i-y, Charlie wrote:
....................................... do I try and pull a new cable thru the existing boxing which also contains the pipework? .................................. Will the new cable be up to being pulled through about 15metres of boxing, 2 walls and 3 corners. No to both questions, I'm afraid! For the first, it's not accepted practice to run mains-carrying cable in the same compartment as pipework, on grounds both of heat (presumably the pipework includes the boiler output - 70-80 degrees?) and of what-happens-if-there's-a- fault-exposing-conductors (like, we're pretty sure the pipework's earthed, but just *how* sure are we?) For the second, pulling cable round three corners, expecially with other pipework in their, is pretty much doomed to failure; and likely even if you manage to damage the insulation. But hey, maybe you can use this as an excuse to buy a nice new SDS drill so you can channel the 4-core neatly ;-) Stefek |
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Pulling cabling through
On 30 Sep 2003 10:56:21 -0700, Charlie wrote:
Now my problem is do I run a new cable in some sticky back trunking along the skirting and behind the kitchen cupboards where it can be seen (concrete floors unfortunately) or do I try and pull a new cable thru the existing boxing which also contains the pipework? Pipework as in CH pipes to from boiler? Ordinary PVC cable doesn't have a particulary high temperature rating. 80C+ from boiler pipework probably exceeds it. I don't think we need be concerned about heating from the load if you use 2.5mm. Will the new cable be up to being pulled through about 15metres of boxing, 2 walls and 3 corners. If you can get clear straight runs you should be able to do it. No chance around a corner, let alone 3. -- Cheers Dave. pam is missing e-mail |
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